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.
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.
Website & Utility Tools
Useful website & utility tools including robots.txt generators, grade calculators, and practical tools for everyday online tasks.
Most popular calculators
Avogadro’s number calculator
Use our Avogadro Number Calculator to find molar mass and number of particles from mass, moles, and Avogadro’s constant.
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.
Beam Deflection Calculator
Use our Beam Deflection Calculator to estimate maximum deflection for simply supported and cantilever beams with point loads, uniform loads, and end moments.
Body Shape Calculator
Body Shape Calculator helps you identify your body type from key measurements and understand which shape category fits you best.
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.
Grams To Calories Calculator
Use our Grams to Calories Calculator to estimate calories from grams of carbs, protein, fat, and alcohol using standard macro calorie factors.
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.
IQ PERCENTILE CALCULATOR
Use our IQ Percentile Calculator to convert an IQ score into percentile rank, percent above, and percent below using SD 15 or SD 16 normal-distribution scales.
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.
Punnett Square Calculator
Punnett Square Calculator to predict genotype and phenotype ratios for monohybrid and dihybrid genetic crosses.
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.
Waist-to-Height Ratio (WHtR) Calculator
Waist-to-Height Ratio (WHtR) Calculator measures WHtR, check risk category, and compare your waist with the half-height target.