What do you want to calculate?

More than 25 free online tools in 6 categories. No signup, fast and reliable.

100% free • Instant result
Mathematics
13 tools
Health
22 tools
Finance
13 tools
Fun & Games
12 tools
Generators
12 tools
Converters
23 tools

Mathematics

Percentage, area, volume, average and age calculators

See all (13)
Paint Calculator
Calculate how much paint you need for a room or wall. Find out if your paint is enough, or how many cans to buy. Free online paint calculator.
Percentage Calculator
Percentage Calculator online: calculate percentages, discounts, ratios and percentage change in seconds. Fast, free and easy to use on NtoolBox.
Area Calculator
Area Calculator online: calculate rectangle, triangle, circle and trapezoid areas from dimensions. Fast, free and easy to use on NtoolBox.
Volume Calculator
Volume Calculator online: calculate cube, sphere, cylinder and cone volumes from dimensions. Fast, free and easy to use on NtoolBox.
Average Calculator
Average Calculator online: calculate mean, median, mode, sum and count from a number list. Fast, free and easy to use on NtoolBox.
Age Calculator
Age and Date of Birth Calculator online: calculate age from date of birth and show years, months and days. Fast, free and easy to use on NtoolBox.
Date Difference Calculator
Calculate the exact number of days, weeks, months and years between any two dates. Free, instant, runs in your browser — no sign-up needed.
Tile Calculator
Calculate how many tiles you need for any room. Enter area, tile size and waste factor — instant result. Free online tile calculator.
Ratio and Proportion Calculator
Solve ratio and proportion problems instantly. Find the unknown in A:B=C:D, simplify ratios. Free online ratio calculator.
VAT Included / Excluded Calculator
Calculate VAT both ways instantly: add tax to a net price or extract tax from a gross price. Enter any rate. Free, browser-based.
Concrete Calculator
Calculate concrete volume and required materials (cement, sand, gravel, water) by shape and grade. Supports slab, cylinder, and staircase calculations.
GCD and LCM Calculator
Calculate the greatest common divisor (GCD) and least common multiple (LCM) of two or more numbers instantly. Free online GCD/LCM calculator.
Standard Deviation Calculator
Calculate mean, variance and standard deviation for any set of numbers. Shows both population and sample standard deviation. Free online statistics calculator.

Health

BMI, BMR, daily water intake and calorie needs calculators

See all (22)
BMI Calculator
BMI Calculator online: estimate body mass index from height and weight. Fast, free and easy to use on NtoolBox.
BMR Calculator
BMR Calculator online: calculate basal metabolic rate and daily energy expenditure. Fast, free and easy to use on NtoolBox.
Daily Water Intake Calculator
Daily Water Intake Calculator online: estimate daily water intake from weight and activity level. Fast, free and easy to use on NtoolBox.
Daily Calorie Needs Calculator
Daily Calorie Calculator online: estimate daily calories for maintenance, weight loss or gain. Fast, free and easy to use on NtoolBox.
Ideal Weight Calculator
Calculate your ideal body weight using Devine, Robinson and Miller formulas. Enter your height and gender to get your healthy weight range instantly.
Pregnancy Due Date Calculator
Calculate your pregnancy due date, current week, trimester and days remaining. Based on Naegele's rule (LMP + 280 days). Free, instant, no registration.
Sleep Cycle Calculator
Find the best time to sleep or wake up based on 90-minute sleep cycles. Enter your wake-up or bedtime and get instant recommendations. Free sleep calculator.
Body Fat Calculator
Calculate your body fat percentage with the US Navy method. Enter height, waist and neck measurements — instant result with category rating. Free online body fat calculator.
Ovulation Calculator — Fertile Window Tracker
Free ovulation calculator: enter your last period date to find your fertile window, ovulation day and next period estimate. Instant, no sign-up required.
Child Growth Percentile Calculator
Calculate your child's height and weight percentile using WHO and CDC growth standards. Free, instant results for boys and girls aged 0-19.
Pregnancy Weight Gain Calculator
Calculate your recommended pregnancy weight gain by week based on your pre-pregnancy BMI. Free tool based on IOM 2009 guidelines.
Biological Age Calculator
Calculate your biological age based on BMR, BMI, activity level, sleep quality, smoking and stress factors. Free, instant results.
Body Analysis
Comprehensive body analysis: calculate BMI, ideal weight range, estimated body fat, and get personalised health tips — all in one tool.
TDEE Calculator
Calculate your TDEE (Total Daily Energy Expenditure), BMR and calorie targets for fat loss, maintenance and muscle gain. Free, instant results.
Dog Age Calculator
Convert your dog's age to human years using the AVMA/AKC size-based lookup table. Shows life stage and biological age. Free, instant.
Cat Age Calculator
Convert your cat's age to human years using the International Cat Care / AAFP formula. Shows life stage and care tips. Free, instant.
Daily Protein Calculator
Calculate your daily protein intake based on weight, activity level and goal. Free, science-backed results.
Walking & Running Calorie Calculator
Calculate calories burned walking, running or cycling. Enter distance and weight to get calories, fat burned, duration and step count.
Clothing Size Calculator
Find your clothing size from your measurements. Bust, waist and hip input with EU/TR, US and UK size comparison for women and men.
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio (WHR) and assess cardiovascular disease risk. Free online WHR calculator with WHO risk categories.
Maximum Heart Rate Calculator
Calculate your maximum heart rate and target heart rate zones for fat burn, cardio, and peak performance. Free online calculator.
Quit Smoking Calculator
Calculate how much money you've saved since quitting smoking, cigarettes avoided, and health milestones reached. Free online quit smoking tracker.

Finance

VAT, loan, compound interest and salary calculators

See all (13)
VAT Calculator
VAT Calculator online: add or remove VAT and see tax amount instantly. Fast, free and easy to use on NtoolBox.
Loan Calculator
Loan Calculator online: calculate monthly payment, total repayment and interest. Fast, free and easy to use on NtoolBox.
Compound Interest Calculator
Compound Interest Calculator online: calculate compound growth by rate, time and compounding frequency. Fast, free and easy to use on NtoolBox.
Simple Interest Calculator
Calculate simple interest instantly. Enter principal, annual rate and time to get interest earned and total amount. Free, no sign-up required.
ROI Calculator
Calculate ROI, net profit, and annualized return on investment. Free, instant results.
Discount Calculator
Calculate the sale price, discount amount, and savings percentage instantly. Works for any original price and discount rate. Free, no signup.
Profit Margin Calculator
Calculate profit margin, markup percentage, and profit amount from cost and selling price. Free, instant, no signup.
Electricity Bill Calculator
Calculate your electricity bill in advance. Enter monthly kWh consumption and unit price to get your estimated bill. Device-based calculation also available.
Savings Goal Calculator — Monthly Savings Plan
Calculate how much you need to save each month to reach your savings goal, or find out how much your fixed monthly savings will grow. Free, instant results.
Bill Splitter
Split a restaurant bill equally among friends. Add tip percentage and calculate what each person owes. Free online bill splitter.
Mortgage Calculator
Calculate your monthly mortgage payment, total interest and full payment schedule. Free online mortgage calculator for any loan amount, rate and term.
TikTok Earnings Calculator
How much does TikTok pay per view? Calculate your TikTok earnings from Creator Fund, brand deals and monthly projections. Free, instant results.
YouTube Earnings Calculator
How much does YouTube pay per view? Calculate your YouTube earnings from AdSense, brand deals and monthly projections. Enter your views, niche and RPM for instant results. Free.

Fun & Games

Dice roller, random number, decision wheel and luck test

See all (12)
Dice Roller
Dice Roller online: roll D4 to D100 dice and see total results instantly. Fast, free and easy to use on NtoolBox.
Random Number Generator
Random Number Generator online: generate one or more random numbers in a chosen range. Fast, free and easy to use on NtoolBox.
Decision Wheel
Decision Wheel online: spin a wheel to choose randomly from your options. Fast, free and easy to use on NtoolBox.
Luck Test
Luck Test online: get a fun random luck score instantly. Fast, free and easy to use on NtoolBox.
Flip a Coin
Flip a virtual coin online and get a fair heads or tails result instantly. Free, cryptographically random, no sign-up needed — NtoolBox.
Name Picker & Raffle
Free online name picker and raffle tool. Enter names, click pick, and get a random winner instantly. Perfect for giveaways, classroom draws, and team selection.
Number Guessing Game
Guess the secret number in as few tries as possible. Choose Easy (1–100), Medium (1–500), or Hard (1–1000). Free browser game, no signup needed.
Team Generator
Randomly split a list of names into balanced teams. Perfect for classrooms, sports, events, and games. Free, instant, no signup.
Zodiac Sign Calculator
Find your zodiac sign by birth day and month. Discover your sign's traits, element, lucky number and lucky color — free and instant.
Personality Color Quiz
Answer 5 quick questions and discover your personality color. Find out if you are a Passionate Leader, Deep Thinker, Bright Optimist or Peaceful Nurturer.
Stopwatch & Countdown Timer
Free online stopwatch with lap times and countdown timer with alarm. Works in your browser, no install needed. NtoolBox.
Anagram Generator & Word Game
Free online anagram generator: scramble any word or phrase and play the word unscramble game. Works with Turkish and English letters. NtoolBox.

Generators

Password, QR code, UUID and lorem ipsum generators

See all (12)
Password Generator
Password Generator online: create strong random passwords in your browser. Fast, free and easy to use on NtoolBox.
QR Code Generator
QR Code Generator online: create QR codes for links or text and download them. Fast, free and easy to use on NtoolBox.
Lorem Ipsum Generator
Lorem Ipsum Generator online: generate placeholder text for layouts and drafts. Fast, free and easy to use on NtoolBox.
UUID Generator
UUID Generator online: generate UUID v4 identifiers for development and testing. Fast, free and easy to use on NtoolBox.
Hash Generator
Free online hash generator. Calculate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes instantly from any text. All hashing runs in your browser — nothing is sent to any server.
Base64 Encoder / Decoder
Free online Base64 encoder and decoder. Encode text to Base64 or decode Base64 back to plain text instantly. JWT, data URIs, MIME — all explained.
Color Code Generator
Pick any color and instantly get HEX, RGB, and HSL codes. Find complementary colors and CSS color names. Copy any format with one click.
Barcode Generator
Generate EAN-13, Code128, UPC-A, ITF and Code39 barcodes instantly. Download as PNG. Free, no registration required.
JSON Formatter & Validator
JSON Formatter online: prettify and validate JSON instantly in your browser. Fast, free and easy to use on NtoolBox.
CSS Gradient Generator
Create beautiful CSS gradients visually. Add color stops, adjust angles, choose linear, radial, or conic type. Copy the CSS code instantly. Free, no signup.
CSS Box Shadow Generator
Generate CSS box-shadow code visually. Control offset, blur, spread, color and opacity with live preview. Copy the CSS instantly.
Color Palette Generator
Generate complementary, analogous, triadic and monochromatic color palettes from any base color. Free online color palette tool for designers.

Converters

Temperature, length, weight, area and speed converters

See all (23)
Temperature Converter
Temperature Converter online: convert Celsius, Fahrenheit and Kelvin instantly. Fast, free and easy to use on NtoolBox.
Length Converter
Length Converter online: convert meters, kilometers, miles, feet and inches. Fast, free and easy to use on NtoolBox.
Weight Converter
Weight Converter online: convert kilograms, grams, pounds, ounces and more. Fast, free and easy to use on NtoolBox.
Area Converter
Area Converter online: convert square meters, hectares, acres and square feet. Fast, free and easy to use on NtoolBox.
Speed Converter
Speed Converter online: convert km/h, mph, m/s, knots and other speed units. Fast, free and easy to use on NtoolBox.
Word & Character Counter
Count words, characters, sentences and paragraphs instantly. Estimates reading time. Free, real-time, runs in your browser — no sign-up needed.
Number System Converter
Convert numbers between binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16) instantly. Free online number base converter.
Time Zone Converter
Convert time between any two time zones instantly. Free online time zone converter for travelers, remote teams, and meeting planning.
Data Storage Converter
Convert data storage units instantly: Bit, Byte, Kilobyte, Megabyte, Gigabyte, Terabyte, Petabyte. Free online data storage converter.
Day Counter
Free online day counter: instantly calculate the difference between two dates, count down to an event, or measure elapsed time. Live second-by-second updates.
Text Case Converter
Convert text to uppercase, lowercase, title case, sentence case, camelCase, PascalCase and snake_case instantly.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates or vice versa. Supports seconds and milliseconds, live current timestamp display.
Text Reverser
Reverse any text instantly, character by character. Supports Unicode, emoji and multi-byte characters.
Date Calculator
Add or subtract days, months and years from any date. Instantly find the resulting date, day of the week, and how far it is from today.
Angle Unit Converter
Convert angle units instantly: degrees, radians, gradians (gon), turns, arcminutes and arcseconds. Free online angle converter.
Frequency Unit Converter
Convert frequency units instantly: Hertz, kilohertz, megahertz, gigahertz, terahertz and RPM. Free online frequency converter.
Cipher Encoder
Encode and decode text with Caesar cipher, ROT13 and Atbash. Free online cipher tool — educational and fun.
Number to Words Converter
Convert numbers to words instantly. 1234 → "one thousand two hundred thirty-four". Supports plain numbers and currency mode. Free and fast.
Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals to numbers instantly. All values from 1 to 3999 are supported. Free online Roman numeral converter.
Morse Code Converter
Convert text to Morse code and Morse code to text. Listen to the real Morse signal with audio playback. Free, no registration.
Energy Unit Converter
Convert energy units instantly: Joule, kJ, MJ, calorie, kcal (food calorie), Wh, kWh and BTU. Ideal for diet, fitness and engineering calculations.
Pressure Unit Converter
Convert pressure units instantly: Pascal, Bar, PSI, atm, mmHg, kPa and more. Free online pressure converter.
Fuel Consumption Calculator
Calculate fuel consumption instantly: enter km and liters to get L/100km, km/L and mpg values. Also calculate trip fuel cost. Free and fast.