Browse All Tools
Every calculator and converter on Smart Utilities Hub, all 55 of them, organized by category. No sign-ups, no ads — just free tools that most run entirely in your browser.
Unit Converters
View category →Length Converter
Instantly convert length units for free — meters, feet, inches, centimeters, kilometers, miles, and yards. No sign-up, accurate results, works on any device.
Mass Converter
Convert mass and weight instantly between kilograms, pounds, ounces, grams, stones, and metric tons — free, accurate to two decimal places.
Temperature Converter
Free temperature converter for Celsius, Fahrenheit, and Kelvin — enter a value and get an instant, precise result with no sign-up, ads, or downloads required.
Volume Converter
Convert volume units instantly and for free — liters, US & UK gallons, cups, milliliters, cubic meters, pints, quarts, and fluid ounces, accurate every time.
Area Converter
Quickly convert area units for free — square meters, square feet, acres, hectares, and square miles, with accurate results and no sign-up needed at all.
Speed Converter
Try our free speed converter for mph, kph, meters per second, knots, and Mach number — instant, accurate conversions that work on any device, no download.
Cooking Volume Converter
Convert cooking measurements for free — cups, tablespoons, teaspoons, milliliters, and fluid ounces — perfect for scaling any recipe up or down accurately.
Timezone Converter
Compare time zones instantly and for free — UTC, EST, PST, GMT, IST, and more, with automatic daylight saving adjustments for accurate cross-region scheduling.
Math Calculators
View category →Basic Calculator
A free online calculator for everyday math — add, subtract, multiply, and divide instantly. Fast, accurate, and works on any device, no sign-up.
Scientific Calculator
Try our free scientific calculator for trigonometry (radians or degrees), logarithms, exponents, and more advanced math — instant, precise results, no sign-up.
Percentage Calculator
Calculate percentages instantly and for free — find what % one number is of another, percentage increase or decrease, all with no sign-up needed at all.
Fraction Calculator
Add, subtract, multiply, and divide fractions for free — convert between fractions, decimals, and mixed numbers, with results simplified automatically.
Square Root Calculator
Calculate the square root, cube root, or any nth root of a number for free with high decimal precision — instant, accurate results, no sign-up needed.
Logarithm Calculator
Free logarithm calculator for natural log, common log, or any custom base — enter a value and get an instant, high-precision result with no sign-up required.
Exponent Calculator
Raise any number to any power for free — compute roots via fractional exponents, with results shown in scientific notation automatically when needed.
Slope Calculator
Calculate the slope between two points for free — enter two coordinates to find rise over run instantly, with no sign-up needed.
Pythagorean Theorem
Solve right triangles for free using the Pythagorean theorem — find the hypotenuse or a missing leg instantly, accurate to any level of precision, no sign-up.
Graphing Calculator
Plot multiple functions overlaid for free with our interactive graphing calculator — each in its own color with a legend, instant results in your browser.
Financial Calculators
View category →Currency Converter
Convert between 161 world currencies instantly using live exchange rates — free, accurate, and refreshed automatically every time you load the tool.
Compound Interest Calculator
Calculate compound interest growth for free with custom compounding frequencies — see year-by-year breakdowns and future value projections, no sign-up.
Mortgage Calculator
Estimate mortgage payments for free with a full amortization schedule — see principal versus interest breakdowns over your entire loan term, instantly.
Investment Growth Calculator
Project investment growth for free with regular contributions — see how your money compounds over time with clear, year-by-year value estimates, no sign-up.
Retirement Calculator
Plan your retirement for free with projections for savings growth, withdrawal rates, and income — includes an optional Social Security estimate, no sign-up.
Tax Calculator
Estimate your income tax for free using progressive tax brackets — enter your income and filing status for an instant, easy-to-read tax estimate, no sign-up.
Salary Converter
Convert salary between hourly, daily, weekly, monthly, and annual pay for free — factor in your work hours for an instant gross-pay breakdown, no sign-up.
Profit Calculator
Calculate gross profit and profit margin for free from your revenue and cost of goods sold — instant, accurate results for pricing any product or service.
Sales Tax Calculator
Calculate sales tax and total price for free — just enter the original amount and tax rate for an instant, accurate breakdown of what you'll owe, no sign-up.
Tip Calculator
Split the bill and calculate tips for free — enter your total and party size for an instant per-person breakdown, accurate down to the cent every time.
Discount Calculator
Work out discounts and sale prices for free — enter the original price and percentage off to get an instant, accurate final price with no sign-up needed.
Markup Calculator
Find markup percentage, selling price, or cost for free — enter any two values to instantly solve for the third, ideal for retail and e-commerce pricing.
Health Calculators
View category →BMI Calculator
Instantly calculate your BMI for free in metric or imperial units — enter your weight and height to get your Body Mass Index and weight category.
Calorie Needs Calculator
Estimate your daily calorie needs for free using the Mifflin-St Jeor equation — enter your age, weight, height, and activity level for an instant result.
Date & Time Tools
View category →Age Calculator
Calculate your exact age for free in years, months, and days — enter your birthdate and optionally a comparison date for an instant, precise result, no sign-up.
Date Difference Calculator
Find the number of days between any two dates for free — perfect for countdowns, deadlines, and scheduling, with instant, accurate results every time.
Add Days to Date Calculator
Add or subtract days from any date for free — enter a start date and a number of days for an instant result that correctly handles month and year boundaries.
Developer Tools
View category →Code Formatter
Format and beautify JavaScript, TypeScript, HTML, CSS, and JSON for free — instant syntax highlighting via Prism.js, with your code never leaving your browser.
JSON Formatter & Validator
Validate and pretty-print JSON for free with configurable indentation. Clear, location-aware error messages for invalid JSON — runs entirely in your browser.
Base64 Encode & Decode
Encode text to Base64 or decode Base64 to text for free, with full Unicode support for accents and emoji. Runs entirely in your browser — nothing is uploaded.
UUID Generator
Generate random version 4 UUIDs for free, using your browser's native crypto API. No sign-up, one click to copy, works entirely on your device.
Hash Generator
Generate SHA-256 or SHA-1 hashes for free using your browser's native Web Crypto API. Includes a clear warning against using it for password storage.
URL Encode & Decode
Encode or decode URLs and query parameters for free. Supports component and full-URI modes, with full Unicode support — runs entirely in your browser.
JWT Decoder
Decode a JWT's header and payload for free, entirely in your browser. Decodes only — never verifies a signature and never asks for a signing secret.
Timestamp Converter
Convert Unix timestamps to dates and back for free, in seconds or milliseconds, with UTC and local time shown. Runs entirely in your browser.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal for free. Supports negative numbers and large values with no precision loss.
Regex Tester
Test regular expressions against sample text for free, with live match and capture group highlighting. Debounced evaluation runs entirely in your browser.
Markdown Previewer
Preview Markdown as safe, rendered HTML live for free. Raw HTML and scripts are never executed — runs entirely in your browser via react-markdown.
Diff Checker
Compare two blocks of text for free, with line-level or word-level diff highlighting. Uses a well-tested diff library — runs entirely in your browser.
Cron Expression Parser
Explain a 5-field cron expression in plain English for free. Covers wildcards, steps, ranges, and lists — runs entirely in your browser.
Text Tools
View category →Case Converter
Convert text between UPPER CASE, lower case, and Title Case for free — paste your text and get an instant result with no sign-up, ads, or downloads required.
Character Counter
Count characters in your text for free, with and without spaces — instant, accurate results for writers, students, and anyone tracking text length, no sign-up.
Word Counter
Count words in any text instantly and for free — perfect for essays, articles, and content writing, with no limit on text length and no sign-up needed.
Text Compressor
Compress and decompress text for free using LZ-String or Pako gzip — reduce text size for storage or transmission, entirely inside your browser, no upload.
Creative Tools
View category →QR Code Generator
Generate custom QR codes for free — embed URLs, text, or contact info, customize colors and sizes, and download instantly with no sign-up or watermark added.
Color Converter
Free color converter for HEX, RGB, HSL, and HSV formats — pick a color and see a live preview update instantly as you type, with no sign-up required at all.
Image Processor
Resize, crop, and edit images for free right in your browser — adjust brightness and apply filters instantly, with nothing ever uploaded to a server at all.