Free Online Calculators and Converters for Fast, Accurate Results
Ajax Calculators offers simple, fast, and practical online calculators for health, finance, math, science, construction, food, unit conversion, and everyday life. Enter your values, get instant results, and use clear explanations to understand how each calculation works.
Explore our categories or start with one of the most popular calculators below to solve common problems quickly and confidently.
Biology & Pets
Biology & pets calculators for animal age, dog pregnancy, dog weight, plant spacing, genetics, Punnett squares, and pet dosage estimates.
Chemistry
Chemistry calculators for molarity, pH, percent yield, theoretical yield, Avogadro’s number, half-life, ideal gas law, atoms, and solutions.
Construction & Home
Construction & Home calculators for framing, roof pitch, square footage, board feet, tank volume, gravel, sand, pipe volume, ramps, and beam deflection.
Ecology & Environment
Ecology & Environment calculators for plastic footprint, biodiversity, Shannon diversity index, sustainability estimates, and ecological measurements.
Education
Free education calculators for grades, GPA, CGPA, marks percentage, final scores, attendance, test results, and academic planning.
Everyday Life
Everyday calculators for age, time, reading time, sleep, date differences, body shape, face shape, balloons, RPM, and daily-use estimates.
Finance
Free finance calculators for loans, mortgages, credit cards, salary, ROI, inflation, VAT, margins, discounts, and other money decisions.
Fitness & Sports
Free fitness & sports calculators for pace, running splits, calories burned, heart rate zones, VO₂ max, bench press, and training goals.
Food & Cooking
Food & Cooking calculators and converters for grams to cups, mL to grams, taco bars, alcohol dilution, calories, ingredients, and recipe planning.
Health
Easy health calculators for calories, BMR, ideal weight, body ratios, cholesterol units, blood values, pregnancy dates, and wellness estimates.
Image & Document Tools
Free image and document tools for WebP, AVIF, image compression, image conversion, PDF conversion, and Open Graph image generation.
Math
Simple math calculators for percentages, fractions, exponents, logarithms, geometry, averages, slope, circumference, and common formulas.
Physics
Physics calculators for velocity, force, pressure, density, energy, work, power, motion, gravity, frequency, resistance, and Ohm’s law.
Statistics
Statistics calculators for standard deviation, variance, percentiles, z-scores, t-tests, sample size, margin of error, and data analysis.
Unit Converters
Fast unit converters for length, volume, weight, time, torque, pixels, fractions, medical units, cholesterol units, and common measurements.
Popular Calculators
Quick Access
Explore the calculators visitors use most for everyday questions, health, science, measurements and practical decisions.
Add Time Calculator
Use our Add Time Calculator to add hours, minutes, seconds, days, weeks, months, and years, then convert the total into your preferred time format.
Basic Calculator
Use this free basic calculator to solve addition, subtraction, multiplication, division, decimals, percentages, and parentheses-based math expressions.
BC to AD Year Difference Calculator
Use our BC to AD Year Difference Calculator to find the years between BC/BCE and AD/CE dates using the no-year-0 formula.
Bird Age Calculator
Use our Bird Age Calculator to convert bird years to human years or human age back to bird age by species or custom lifespan.
Face Shape Calculator
Use our Face Shape Calculator to estimate your likely face shape from forehead, cheekbone, jawline, and face length measurements plus chin shape.
Favicon Generator
Create favicon.ico, PNG favicons, Apple and Android icons, a web manifest and installation code. Download individual files or a ZIP.
Helium Balloons Calculator
Use our Helium Balloons Calculator to estimate lift per balloon, total helium volume, and how many helium balloons you need to lift a given weight.
Image Color Picker
Upload or paste an image and pick any pixel to find HEX, RGB, HSL, OKLCH and other color values. Extract, copy and download balanced color palettes free.
mg to mL Calculator
Use our mg to mL Calculator to convert weight and volume using liquid density, preset liquids, or medication concentration in mg/mL or mg/5 mL.
Number to Million Converter
Number to Million Converter to express large figures in millions instantly for finance, reports, and easy reading.
PAY RAISE CALCULATOR
Pay Raise Calculator helps you calculate salary increases, raise percentages, and new pay amounts in seconds.
RPM Calculator
Use our RPM Calculator to find engine RPM from speed or vehicle speed from RPM using overall gear ratio and tire diameter, plus wheel RPM and tire circumference.