All Tools - hello-tools

Calculate Body Mass Index and weight category

Estimate body fat percentage using Navy formula

Estimate blood alcohol content

Calories burned during various exercises

Find your ideal weight using medical formulas

Running pace, speed, distance, or time calculator

Optimal bedtime and wake-up times based on sleep cycles

Daily water intake recommendation based on weight and activity

Convert dog/cat age to human years

Track fertile window and ovulation day

Estimate due date and pregnancy progress

Calculate due date from last menstrual period

Total Daily Energy Expenditure calculator

BMR, TDEE, BMI and macros for weight goals

Monthly car payment, interest, and total cost

Investment growth with compound interest

Compound Annual Growth Rate for investments

Monthly payments, interest, and amortization

Monthly mortgage payments with amortization

Equated Monthly Installment for loans

Time and interest to pay off credit card debt

Project investment growth over time

How much to save for retirement using 4% rule

Systematic Investment Plan returns calculator

Simple interest on loans and investments

Convert annual salary to hourly, daily, weekly, monthly

US state sales tax with 2026 rates

Add or remove Value Added Tax

Money value change over time using CPI

Calculate markup, selling price, and profit margin

Calculate tip amount and split bill

Real-time exchange rates for world currencies

Overtime pay with time-and-a-half and double time

Final price after discount percentage

Hundreds of units across length, weight, temperature, volume, area, speed, pressure

Recipe units: cups, ml, tbsp, tsp, oz, grams, Fahrenheit, Celsius

Bytes, KB, MB, GB, TB, PB conversion

Difference between two dates, add/subtract days

Countdown to any future date

Exact duration between two datetimes

Convert time between 400+ IANA timezones

Add or subtract hours, minutes, seconds

Countdown timer with hours, minutes, seconds

Decimal, binary, hex, octal conversion

Calculate V, I, R, P from any two values

Speed, distance, or time calculator

Trip fuel cost based on distance, efficiency, price

Mean, median, mode, and range of numbers

All common percentage calculations

Add, subtract, multiply, divide fractions

Simplify ratios or find missing values

Encode text to Base64 or decode back to plain text

MD5, SHA-256, SHA-512 hashes

Decode and inspect JSON Web Tokens

Pretty print, minify, validate JSON

Test regular expressions with match highlighting

Compare two texts with color-coded differences

Uppercase, lowercase, title case, sentence case

Count characters, words, lines, sentences

Words, characters, sentences, paragraphs, reading time

Word counter, character counter, case converter, text reverser

Placeholder text for designers and developers

Search, browse, and copy emojis

Encode or decode percent-encoded URLs

Random UUID v4 identifiers

Strong secure passwords with customizable options

Generate QR codes for URLs, text, phone numbers

Scan and decode QR codes from images

HEX, RGB, HSL color format conversion

WCAG AA/AAA contrast ratio checker

Area of rectangle, square, circle, triangle

Photo file sizes, aspect ratios, print sizes, resolution

Write Markdown, see live HTML preview

Check your public IPv4 and IPv6 address

Random numbers, coin flips, dice rolls, choices

Convert images to ASCII art

Grade Point Average on 4.0, 4.3, 4.5 scale

Class grade, final exam score, cumulative GPA

Decimal, binary, hex, octal conversion

Numbers to Roman numerals and back

Trigonometric, logarithmic, powers, factorial, pi

Mean, variance, std dev, median, min, max, range

Mental arithmetic trainer with CPM tracking

WPM, accuracy in English and Korean

Virtual coin flip with true random results

Roll D4, D6, D8, D10, D12, D20, D100

Powerball, Mega Millions, EuroMillions, UK Lotto

Love percentage, FLAMES, zodiac compatibility

Draughts game with AI opponent, 5 difficulties

Classic four-in-a-row strategy game

Five in a row on 15x15 grid

Classic logic puzzle, 3 difficulties

Klondike patience card game

5 difficulty levels, hints, pencil marks

Single or three-card spreads

Jacks or Better casino card game

Artillery tank battle game

16-type personality assessment

Find your zodiac animal by birth year

First and last names for characters, usernames

MD5, SHA-256, SHA-512 hashes

Decode and inspect JSON Web Tokens

Strong secure passwords with customizable options

Exact age in years, months, days

How-to guides for calculators and tools

Learn about our free online tools collection

Data practices and your rights

Rules for using our free online tools