Free Online Tools for Everyone
50+ free calculators, converters, and developer tools. Fast, private, no sign-up required.
Popular Tools
Mortgage Calculator
Calculate your monthly mortgage payment, total interest, and amortization details. Enter home price, down payment, rate, and loan term.
Compound Interest Calculator
Calculate compound interest with regular contributions. See how your investments grow over time with monthly, quarterly, or annual compounding.
BMI Calculator
Calculate your Body Mass Index (BMI) using weight and height. Supports pounds/kilograms and feet-inches/centimeters with instant category results.
Percentage Calculator
Calculate percentages instantly: find X% of Y, what percent X is of Y, or the percentage change between two numbers. Fast and accurate.
Word Counter
Count words, characters, sentences, paragraphs, and estimate reading time in real time. Paste or type your text for instant live statistics.
Password Generator
Generate strong, random passwords with customizable length and character types. Includes uppercase, lowercase, numbers, and symbols.
JSON Formatter & Validator
Format, minify, and validate JSON data online. Pretty-print with 2-space indentation, compress to single line, or check for syntax errors with position info.
Unit Converter
Convert between units of temperature, weight, length, area, volume, speed, and data storage. All conversions are bidirectional with a swap button included.
Finance
Mortgage Calculator
Calculate your monthly mortgage payment, total interest, and amortization details. Enter home price, down payment, rate, and loan term.
Loan Calculator
Calculate monthly loan payments, total interest, and total cost for any loan. Enter loan amount, interest rate, and term to get results.
Compound Interest Calculator
Calculate compound interest with regular contributions. See how your investments grow over time with monthly, quarterly, or annual compounding.
ROI Calculator
Calculate return on investment (ROI) percentage and net profit or loss. Enter your initial investment and final value to see your returns.
Salary Calculator
Convert salary between hourly, weekly, biweekly, monthly, and annual pay. Enter any pay rate and see all equivalent salary breakdowns instantly.
Tip Calculator
Calculate tip amount, total bill, and per-person cost when splitting. Choose preset tip percentages or enter a custom amount for any bill.
Tax Calculator
Estimate US federal income tax using 2024 tax brackets. See tax owed, effective rate, marginal rate, and after-tax income by filing status.
Currency Converter
Convert between 15+ major world currencies with live exchange rates. Fallback rates included so conversions always work, even offline.
Inflation Calculator
Calculate the effect of inflation on purchasing power over time. See how much past dollars are worth today or how future costs will change.
Net Worth Calculator
Calculate your net worth by listing all assets and liabilities. Add or remove items dynamically and see total assets, debts, and net worth.
Health & Fitness
BMI Calculator
Calculate your Body Mass Index (BMI) using weight and height. Supports pounds/kilograms and feet-inches/centimeters with instant category results.
Calorie Calculator
Calculate your daily calorie needs using the Mifflin-St Jeor equation. Get maintenance, weight loss, and weight gain targets based on your activity.
BMR Calculator
Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation. Find out how many calories your body burns at rest each day.
Body Fat Calculator
Estimate your body fat percentage using the US Navy method. Enter waist, neck, height, and hip measurements to get fat mass and lean mass results.
Pregnancy Due Date Calculator
Calculate your estimated due date from your last menstrual period. See your current week of pregnancy, trimester, and days remaining.
Water Intake Calculator
Calculate your recommended daily water intake based on body weight, activity level, and climate. Get results in ounces, liters, and glasses.
Ideal Weight Calculator
Find your ideal body weight using four proven medical formulas: Devine, Robinson, Miller, and Hamwi. Compare results by height and gender.
Macro Calculator
Calculate your daily macronutrient targets for protein, carbs, and fat. Choose from balanced, low-carb, high-protein, or keto diet profiles.
Heart Rate Zone Calculator
Calculate your target heart rate training zones using the Karvonen formula. Enter age and resting heart rate to see all five intensity zones.
BAC Calculator
Estimate your Blood Alcohol Content using the Widmark formula. Enter drinks, weight, gender, and time elapsed to see BAC and sobriety time.
Math
Percentage Calculator
Calculate percentages instantly: find X% of Y, what percent X is of Y, or the percentage change between two numbers. Fast and accurate.
Fraction Calculator
Add, subtract, multiply, and divide fractions with ease. Get results as simplified fractions and decimals. Supports mixed numbers too.
Scientific Calculator
Evaluate math expressions with support for exponents, square roots, trigonometry, logarithms, and constants like pi and e. Free and fast.
GPA Calculator
Calculate your weighted GPA from course grades and credit hours. Add multiple courses, select letter grades, and get your cumulative GPA instantly.
Grade Calculator
Calculate your grade percentage and letter grade from points earned and total points. See where you stand with the standard A-F grading scale.
Average Calculator
Calculate mean, median, mode, range, sum, min, and max from a list of numbers. Enter comma-separated values and get full statistical summary instantly.
Square Root Calculator
Find the square root and cube root of any number. Also tells you whether a number is a perfect square. Supports decimals and large numbers.
Exponent Calculator
Calculate the result of raising a base number to any exponent (power). Supports negative exponents, decimals, and very large or small results.
Text & Writing
Word Counter
Count words, characters, sentences, paragraphs, and estimate reading time in real time. Paste or type your text for instant live statistics.
Character Counter
Count characters with and without spaces, plus word and line counts, all in real time. Perfect for tweets, meta descriptions, and SMS limits.
Case Converter
Convert text between UPPER CASE, lower case, Title Case, Sentence case, camelCase, snake_case, and kebab-case with a single click and copy.
Lorem Ipsum Generator
Generate lorem ipsum placeholder text for your designs and mockups. Choose paragraphs, sentences, or words with custom count.
Text to URL Slug Converter
Convert any text into a clean, URL-friendly slug. Removes special characters, replaces spaces with hyphens, and lowercases text.
Password Generator
Generate strong, random passwords with customizable length and character types. Includes uppercase, lowercase, numbers, and symbols.
Random String Generator
Generate random strings with custom length and character sets. Choose from alphanumeric, alphabetic, numeric, hex, or custom characters.
Developer
JSON Formatter & Validator
Format, minify, and validate JSON data online. Pretty-print with 2-space indentation, compress to single line, or check for syntax errors with position info.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings back to text online. Handles UTF-8 characters properly using TextEncoder and TextDecoder for accurate output.
Hash Generator
Generate MD5, SHA-1, and SHA-256 hashes from any text instantly. Compare hash outputs side by side with one-click copy for checksums and data integrity checks.
Color Picker & Converter
Pick any color and convert between HEX, RGB, and HSL formats instantly. Includes a visual color preview swatch and one-click copy buttons for each format.
Regex Tester
Test regular expressions against text with real-time match highlighting. View match count, captured groups, and toggle global, case-insensitive, or multiline.
URL Encoder / Decoder
Encode or decode URLs and query parameters online. Converts special characters to percent-encoded format using encodeURIComponent and decodeURIComponent.
JWT Decoder
Decode JSON Web Tokens to inspect header and payload claims. View expiration status, issued-at time, and all token claims as formatted JSON in the browser.
UUID Generator
Generate random UUID v4 identifiers using crypto.randomUUID. Create up to 50 UUIDs at once with one-click copy for individual values or the entire batch.
Date & Time
Age Calculator
Calculate your exact age in years, months, and days from your birthday. See total days alive, countdown to next birthday, and your zodiac sign instantly.
Date Difference Calculator
Calculate the exact difference between two dates in years, months, days, total days, weeks, and hours. Useful for project timelines, age gaps, and deadlines.
Countdown Timer
Set a target date and time to see a live countdown in days, hours, minutes, and seconds. Updates every second with automatic cleanup on unmount or completion.
Timezone Converter
Convert time between 20+ major world timezones instantly. Uses Intl.DateTimeFormat for accurate DST-aware conversions with date and time inputs for precision.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates. Shows a live-updating current timestamp and supports timestamp-to-date and date-to-timestamp modes.
Days Until Calculator
Find out how many days, weeks, and hours remain until holidays like Christmas, New Year, Valentine's Day, Halloween, July 4th, or any custom date you choose.