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Free Online Calculators

GetFastCalc gives you 100+ free calculators and tools for math, finance, health, science, and more. Everything runs in your browser — no signup, no data stored, instant results.

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🤖

AI Prompt Workspace

Cost, token, and prompt tools for ChatGPT, Claude, and Gemini.

📦

FBA Seller Dashboard

Profit, fees, ACOS, and reorder tools for Amazon sellers.

📈

Quant Trader Desk

Risk, position sizing, and performance metrics for traders.

💻

Developer Toolkit

Encoding, formatting, and timestamp tools for developers.

💰

Finance Hub

Compound interest, loans, savings, and budget calculators.

💪

Health Tracker

BMI, body fat, water intake, and BMR/TDEE calculators.

🎨

Designer Toolkit

Color, contrast, typography, and responsive image tools.

Want to build your own dashboard? Save tools, reorder cards, and mix categories.

Open Workbench →

Date & Time

2 tools

📅

Age Calculator

Find your exact age in years, months, and days

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🎉

Holiday Calculator

Find public holidays and calculate days until the next one

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AI

27 tools

📏

AI Context Window Manager

Manage your context window effectively

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💰

AI Cost Comparator

Compare costs across AI models

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🖼️

AI Image Cost Calculator

Calculate costs for AI-generated images.

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📊

AI Model Comparator

Compare different AI models side by side.

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🧹

AI Prompt Cleaner

Refine your prompts for clarity.

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🔧

AI Prompt Variable Generator

Generate dynamic variables for prompts

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📏

Context Window Calculator

Optimize your AI prompt context.

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🪟

Context Window Optimizer

Maximize your AI's context window usage.

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📏

Context Window Usage Calculator

Calculate your context window usage easily.

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🧹

Prompt Cleaner

Clean and optimize your AI prompts.

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🧹

Prompt Cleaner Tool

Refine your prompts for clarity and impact.

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💰

Prompt Cost Calculator

Estimate your AI prompt costs quickly.

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💰

Prompt Cost Comparator

Compare costs for AI prompts instantly.

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💰

Prompt Cost Comparison

Compare costs of different prompts

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📝

Prompt Formatter

Format your prompts for better AI results.

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✨

AI Prompt Optimizer Tool

Enhance your prompts for better results

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💰

Prompt Token Cost Calculator

Estimate your prompt's token cost easily.

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🧮

Prompt Token Counter

Count tokens in your prompts easily

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🛠️

Prompt Token Optimizer

Optimize prompts to save tokens

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💡

Prompt Token Saver

Optimize your prompts to save tokens

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🔧

Prompt Variable Generator

Create dynamic variables for your prompts.

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🔍

Prompt Version Comparator

Compare different prompt versions

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📊

Prompt Version Compare

Compare different versions of your prompts.

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🔍

Prompt Version Comparer

Compare different versions of prompts

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📊

Token Cost Forecast

Estimate future token costs for your projects

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✂️

Token Splitter

Effortlessly split your prompts into tokens.

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✂️

Token Splitter Tool

Split your text into manageable token chunks.

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Ecommerce

6 tools

📊

Amazon ACoS Calculator

Calculate ACoS, TACoS, max CPC bid, and true ad profitability

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🏷️

FBA Fee Calculator

Calculate Amazon FBA fulfillment, referral and storage fees by size tier

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📦

FBA Carton Packing Calculator

Pack FBA shipments smarter — visualize box layout, avoid wasted space and Amazon oversize fees

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💰

FBA Profit Calculator

Calculate net profit, ROI and margin for any Amazon FBA product

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📦

FBA Reorder & Restocking Calculator

Never run out of stock — know exactly when to reorder and how many units to buy

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🚢

Import Duty Calculator

Estimate US import duties, tariffs and customs fees for any product

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Developer

37 tools

📡

API Response Time Calculator

Calculate and analyze API response times.

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🔢

Number Base Converter

Convert numbers between any bases — binary, octal, decimal, hex, and more

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🔐

Base64 Encoder / Decoder

Encode and decode Base64 and URL-encoded strings instantly

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📊

Code Complexity Calculator

Evaluate your code's complexity.

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⚙️

Code Optimization Calculator

Analyze code efficiency and performance

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⏱️

Cron Expression Generator & Explainer

Build cron schedules visually, understand any cron string instantly

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📏

CSS Grid Layout Calculator

Design responsive grids effortlessly.

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📐

CSS Unit Converter

Convert px to rem, em, vw and more — instant CSS unit calculations

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🎨

CSS Variables Generator

Build a custom color palette and export ready-to-use CSS variables and Tailwind config

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⚡

Dev API Performance Calculator

Evaluate your API performance metrics

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💰

Dev Budget Calculator

Estimate your development costs.

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💰

Dev Cost Estimator

Estimate development project costs.

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🔗

Dev Dependency Analyzer

Analyze project dependencies efficiently.

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🎓

Dev Education Cost Calculator

Estimate training costs for developers

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💰

Dev Project Budget Calculator

Estimate your project costs accurately.

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🖥️

Dev Sandbox Calculator

Estimate resource needs for your dev environment

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🔒

Dev Security Risk Calculator

Evaluate security risks in your projects.

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⏳

Dev Time Tracking Calculator

Track your development time efficiently.

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♿

Dev Tool Accessibility Checker

Test your dev tool for accessibility issues.

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🤝

Dev Tool Collaboration Optimizer

Improve team collaboration on your dev projects.

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🔍

Dev Tool Comparison Calculator

Compare multiple development tools side by side.

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💰

Dev Tool Cost Calculator

Estimate your development tool expenses

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⚙️

Dev Tool Efficiency Calculator

Measure your development tool effectiveness.

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📋

Dev Tool Feature Prioritizer

Prioritize features for your dev tool effectively.

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🔗

Dev Tool Integration Planner

Plan your tool integrations effectively

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📊

Dev Tool Performance Calculator

Measure your dev tools' effectiveness.

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🔍

Dev Tool Selection Guide

Find the right tools for your project.

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🛠️

Dev Tool UI Research Helper

Prepare for user interface research effortlessly.

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📊

Dev Tool Usage Analytics Tracker

Track and analyze usage of your dev tool.

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🛠️

Dev Tool Usage Tracker

Monitor and analyze your dev tool usage

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🔍

Dev UX Research Calculator

Estimate your UX research costs

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⏱️

Developer Time Tracking Calculator

Track your development time efficiently.

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🔍

Online Diff Checker

Compare two texts, files, or code snippets side by side

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📋

JSON & CSV Formatter / Validator

Format, validate, and convert JSON and CSV instantly in your browser

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🔐

JWT Decoder & Security Checker

Decode and inspect any JWT token — with security analysis

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⏱️

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates instantly

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🔗

URL Encoder / Decoder

Encode or decode URL strings instantly — no signup, no ads

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Health

8 tools

⚖️

BMI Calculator

Calculate your Body Mass Index instantly

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🔥

BMR & TDEE Calculator

Find your daily calorie burn and set the perfect target for your goal

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💪

Body Fat Percentage Calculator

Calculate your body fat % using the US Navy measurement method

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⚖️

Ideal Weight Calculator

Find your ideal weight using 4 medical formulas + healthy BMI range

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🌸

Ovulation & Cycle Tracker

Predict fertile window, ovulation date, and next period

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🏃

Running Pace Calculator

Calculate your running pace, speed, and finish time

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😴

Sleep Calculator

Find the best time to wake up or go to sleep

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💧

Daily Water Intake Calculator

How much water should you drink per day? Find your personalized target

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Finance

17 tools

📊

Budget Calculator

Track income vs. expenses and see exactly where your money goes

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🚗

Car Lease Calculator

Calculate your lease payments quickly!

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📈

Compound Interest Calculator

See how your money grows over time with compound interest

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💱

Currency Converter

Convert currencies with live exchange rates

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💳

Debt Repayment Calculator

See how long to pay off debt and how much interest you'll pay

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🏷️

Discount Calculator

Calculate sale price, savings, and original price from any discount percentage

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💰

Finance Charge Calculator

Calculate your finance charges effortlessly!

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📉

Inflation & Purchasing Power Calculator

What is $10,000 from 10 years ago worth today?

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📈

Investment Return Calculator

Calculate ROI, CAGR, and future value for any investment

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🏦

Loan Calculator

Calculate monthly payments, total interest, and amortization schedule

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Percentage Calculator

Calculate percentages, increases, decreases, and more

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💹

Profit Margin Calculator

Calculate gross profit margin, markup, and revenue — instant results

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🏠

Rent vs Buy Calculator

Is it cheaper to rent or buy a home? Find out in 60 seconds.

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💰

Retirement Savings Calculator

See how much you need to save to retire comfortably

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🏦

Savings Goal Calculator

Plan your savings easily!

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🧾

Income Tax Calculator

Calculate income tax for USA, UK, Canada, Australia and more

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🍽️

Tip Calculator

Calculate tip amount and split the bill instantly

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SEO

17 tools

🔍

Canonical Link Validator

Check your canonical links for issues

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🔗

Canonical URL Checker

Verify your canonical URLs

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📝

Content Optimization Checker

Optimize your content for SEO

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🖼️

Image Alt Text Generator

Create SEO-friendly alt text for images

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🔍

Keyword Density Analyzer

Analyze your keyword use

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🔍

Keyword Density Checker

Analyze keyword usage on your pages.

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🔗

Link Building Opportunity Finder

Identify potential link building prospects

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📄

Meta Description Generator

Craft perfect meta descriptions

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🔑

Meta Keyword Generator

Generate optimized meta keywords quickly

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📝

Meta Title Generator

Create compelling meta titles instantly

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⏳

Reading Time Calculator

Estimate reading time for your content

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🤖

Robots.txt Generator

Easily create your robots.txt file

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📊

Schema Markup Generator

Create structured data for your site

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🔍

Schema Markup Generator

Generate structured data markup

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📝

SEO Title Generator

Create catchy and optimized titles.

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📝

Title Optimization Tool

Generate compelling SEO titles

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📝

Title Optimizer

Generate compelling titles instantly

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Travel

4 tools

🌍

Carbon Footprint Travel Calculator

Calculate your trip's carbon impact.

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👥

Group Trip Cost Splitter

Split trip costs among friends easily.

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💰

Travel Expense Estimator

Estimate your trip costs quickly.

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⏳

Travel Time Calculator

Calculate how long your trip will take.

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Converter

5 tools

🌡️

Celsius to Fahrenheit Converter

Convert °C to °F — and back — with instant visual feedback

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📏

CM to Inches Converter

Instantly convert centimeters to inches — and back

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🍳

Grams to Ounces Converter

Convert grams to ounces (and oz to g) instantly

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⚖️

KG to LBS Converter

Convert kilograms to pounds — and back — instantly

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📐

Meters to Feet Converter

Convert meters to feet and feet to meters instantly

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Text

2 tools

📝

Character Counter for Social Media

Real-time character & word count for Twitter, LinkedIn, Instagram, and more

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📰

SEO Headline Analyzer

Score your title for clicks, emotion, SEO power, and length

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Design

12 tools

🎨

Professional Color Palette Lab

Explore curated industry palettes with HEX, Tailwind, CMYK, and Pantone reference

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🎨

Contrast Checker Tool

Ensure accessible color combinations

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📁

Icon Library Browser

Search and find the perfect icons

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🎨

Dark Tech Color Palette

High-impact dark UI palette for gaming, cybersecurity, and developer tools. Deep blacks with electric neon accents.

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🎨

Eco Green Color Palette

Nature-inspired organic palette for sustainability brands, wellness, and environmental products. Deep forest greens and warm earth tones.

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🎨

Medical Blue Color Palette

Trustworthy, sterile palette for healthcare and medical applications. Calming blues and whites communicate safety and precision.

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🎨

Retro Film Color Palette

Warm, faded tones inspired by analog photography. Earthy amber, dusty rose, and worn-paper cream.

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🎨

Minimal SaaS Color Palette

Clean, high-contrast palette used by modern SaaS products. Neutral grays anchored by a confident indigo accent.

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📱

Responsive Image Calculator

Optimize images for different screens

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🖼️

SVG Clip Path Generator

Easily create custom clip paths

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🔤

Typography Compare Lab

Compare two Google Fonts side-by-side — instant preview, no signup

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🔤

Typography Scale Generator

Create harmonious font sizes effortlessly

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Cooking

4 tools

⏲️

Cooking Time Calculator

Calculate cooking times easily.

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🥄

Ingredient Substitution Calculator

Find substitutes for missing ingredients.

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🥡

Leftover Recipe Generator

Turn leftovers into delicious meals.

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🍽️

Serving Size Calculator

Adjust recipes for any number of servings.

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Quant

4 tools

🕯️

Crypto Chart Analyzer

Candlestick chart with EMA, SMA, RSI & Bollinger Bands — runs in your browser

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🎯

Kelly Criterion Calculator

Calculate optimal bet size using Kelly formula — maximize long-run growth

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📊

Position Size Calculator

Calculate your position size and manage trading risk — free, instant, browser-only

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📊

Sharpe Ratio Calculator

Measure risk-adjusted return of your portfolio or strategy

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Crypto

3 tools

🪙

Crypto Market Cap Comparator

If coin X reached coin Y's market cap, what would its price be?

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📐

Position Size Calculator

Never risk more than you can afford — calculate the perfect position size

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🎯

Take Profit / Stop Loss Calculator

Calculate your exact PnL, R:R ratio and liquidation price before you trade

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Productivity

4 tools

🎯

Daily Goal Tracker

Set and track your daily goals easily

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📋

Task Priority Calculator

Rank your tasks for maximum efficiency

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🗓️

Time Blocking Scheduler

Plan your day with time blocks

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⚖️

Work-Life Balance Calculator

Assess your work-life balance today

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Utilities

4 tools

😊

Emoji Picker

Search, copy, and use any emoji instantly

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🎓

GPA Calculator

Calculate your GPA instantly from letter grades or percentages

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🔤

Text Case Converter

Convert text to uppercase, lowercase, title case, camelCase, and more

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📝

Word Counter

Count words, characters, sentences, and reading time

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Fitness

4 tools

🧘

Fitness Age Calculator

Discover your fitness age now!

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🏋️‍♀️

Fitness Level Quiz

Assess your fitness level today!

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💧

Hydration Needs Calculator

Calculate your daily hydration needs!

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🍏

Macro Tracker Calculator

Track your macros effectively!

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Home

3 tools

💡

Home Appliance Energy Calculator

Calculate energy costs for your appliances.

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🏡

Home Loan Affordability Calculator

Determine how much home you can afford.

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🛠️

Home Tool Cost Calculator

Estimate your home tool expenses easily.

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Content

1 tools

📝

Markdown Previewer

Write and preview Markdown live — clean editor, instant rendered output

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Security

1 tools

🔐

Password Generator

Generate strong, secure passwords instantly

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Generators

2 tools

📱

QR Code Generator

Generate a QR code for any text or URL instantly

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🎲

Random Number Generator

Generate truly random numbers instantly — single, list, or dice

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Math

1 tools

🧮

Scientific Calculator

Full-featured scientific calculator — trig, log, powers and more

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Popular Calculators

%Percentage Calculator ⚖️BMI Calculator 🧮Scientific Calculator 📈Compound Interest Calculator 🧾Income Tax Calculator 📅Age Calculator 🍽️Tip Calculator 🔐Password Generator

🗂️

Build your personal workbench

Open →

Save tools, create collections, and access everything in one place. Try the FBA Seller Kit to get started.

📦FBA Seller Kit 💪Health & Fitness 💰Finance & Money

About GetFastCalc

GetFastCalc is a free online calculator hub with 100+ tools across math, finance, health, science, developer utilities, and more. Every tool runs entirely in your browser — there is no server-side processing, no account required, and no data is ever stored.

Whether you need a percentage calculator, a BMI calculator, a scientific calculator, or developer tools like a base converter or Base64 encoder, GetFastCalc has you covered. Results are instant — just type a value and the answer appears immediately.

All calculators follow well-established formulas and are updated regularly. GetFastCalc is trusted by students, professionals, developers, and everyday users who need fast, accurate answers without any friction.