All calculators — the complete hub

Estimate your monthly mortgage payment, total interest paid, and full amortization schedule from home price, down payment, interest rate, and loan term.

Calculate monthly payments, total interest, and payoff schedule for personal, student, auto, or business loans from principal, APR, and term length.

Estimate monthly car payments and total loan cost from vehicle price, down payment, trade-in value, sales tax, APR, and financing term in months.

See how savings grow over time with compound interest from a starting balance, monthly contributions, interest rate, compounding frequency, and time horizon.

Project the future value of a portfolio from an initial investment, monthly or annual contributions, expected annual return, and investment time horizon.

Estimate how much you must save each month to retire comfortably based on current age, retirement age, current savings, income, and expected return rate.

Adjust historical or future dollar amounts for inflation using CPI-style rates to compare purchasing power across any two years or decades side by side.

Estimate US federal income tax and take-home pay from gross income, filing status, and standard deduction using current tax brackets for the 2024 tax year.

Calculate gratuity and split the bill fairly between any number of people from bill amount, tip percentage, and party size, with per-person totals shown.

Convert pay between hourly, daily, weekly, biweekly, monthly, and annual salary from a base wage and standard hours worked per week for quick comparisons.

Calculate Body Mass Index and see your WHO weight category from height and weight in either metric (cm, kg) or imperial (ft/in, lb) units instantly.

Estimate the calories your body burns at rest using the Mifflin-St Jeor equation from age, sex, height, and weight — the baseline for any calorie plan.

Estimate daily calorie needs (TDEE) for weight loss, maintenance, or gain from age, sex, height, weight, and activity level using the Mifflin-St Jeor formula.

Estimate body fat percentage using the US Navy tape method from neck, waist, and hip circumferences along with height, then compare against fitness categories.

Compute ideal body weight for men and women from height using the Devine, Robinson, Miller, and Hamwi formulas so you can compare classical medical benchmarks.

Estimate your pregnancy due date, current gestational age, and trimester milestones from the first day of your last menstrual period using Naegele's rule.

Calculate running pace, finish time, or distance for 5K, 10K, half marathon, or marathon workouts from any two of pace, time, and distance in km or miles.

Compute daily protein, carbohydrate, and fat targets in grams and calories from a TDEE, goal split, and body weight — tune macros for cutting or bulking.

Estimate daily water intake needs in ounces and liters from body weight, activity level, and climate to stay properly hydrated throughout the day.

Compute all five training heart rate zones from age and resting heart rate using the Karvonen formula, ideal for endurance, tempo, and interval sessions.

Calculate percent of a number, percentage change, and percent difference between two values — with reverse solving for base, part, and percent supported.

Free online scientific calculator with trigonometry, logarithms, exponents, square roots, factorials, parentheses, and memory — no download or install needed.

Add, subtract, multiply, divide, and simplify proper, improper, and mixed fractions with automatic reduction to lowest terms and decimal equivalents shown.

Simplify ratios to lowest terms and solve for a missing term in a proportion (A:B = C:D) from any three known values — perfect for recipes, maps, and scale.

Generate random integers within any minimum and maximum range, with or without duplicates, for raffles, lotteries, sampling, and quick decision making.

Compute sample and population standard deviation, variance, mean, and sum of squares from any comma or space-separated dataset with step-by-step results.

Compute mean, median, mode, range, variance, and standard deviation from any list of numbers to quickly summarize a dataset with descriptive statistics.

Round any number to a chosen decimal place, whole number, or significant figures using standard, banker's, ceiling, or floor rounding modes side by side.

Compute powers, roots, and exponents with any positive, negative, decimal, or fractional base and exponent — including a^b, cube roots, and nth roots.

Find the greatest common factor (GCF) and least common multiple (LCM) of two or more integers with prime factorization steps shown for each input value.

Convert length between meters, kilometers, centimeters, millimeters, inches, feet, yards, and miles instantly with high-precision decimal output values.

Convert weight and mass between kilograms, grams, pounds, ounces, stone, and metric tonnes with precise conversion factors and multiple decimals of accuracy.

Convert temperatures between Celsius, Fahrenheit, and Kelvin with exact conversion formulas — ideal for cooking, science, weather, and international travel.

Convert area between square feet, square meters, square yards, acres, hectares, and square kilometers for real estate, construction, and land measurement.

Convert volume between liters, milliliters, US and UK gallons, quarts, pints, cups, fluid ounces, and cubic meters for cooking, chemistry, and engineering.

Convert time between seconds, minutes, hours, days, weeks, months, and years using average calendar values — handy for durations and timeline planning.

Convert speed between miles per hour, kilometers per hour, meters per second, feet per second, and knots for running, driving, sailing, and aviation.

Convert digital data storage between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes using both decimal (SI) and binary (IEC) units.

Convert energy between joules, kilojoules, calories, kilocalories, kilowatt-hours, watt-hours, BTU, and electronvolts for physics, nutrition, and utility bills.

Convert pressure between psi, bar, kilopascals, megapascals, atmospheres, torr, and mmHg for engineering, weather, tire, and scientific measurements.

Calculate your exact age in years, months, weeks, days, hours, and minutes from your date of birth to any target date, plus days until your next birthday.

Calculate the number of days, weeks, months, and years between two dates, including or excluding the end date — great for contracts, projects, and anniversaries.

Add or subtract hours, minutes, and seconds across multiple durations, or split a total time into equal segments — with support for HH:MM:SS style inputs.

Compute grade point average on the 4.0 scale, weighted by credit hours, from letter or numeric grades across any number of courses in a semester or year.

Compute your final class grade from assignment weights and scores, plus the minimum score needed on remaining work to reach a target letter grade or percent.

Generate strong random passwords with configurable length, uppercase, lowercase, numbers, symbols, and excluded ambiguous characters — generated locally in-browser.

Convert between Arabic numbers (1-3999) and Roman numerals (I, V, X, L, C, D, M) with correct subtractive notation — useful for dates, chapters, and outlines.

Estimate total fuel cost for any trip from distance, vehicle fuel economy in MPG or L/100km, and gas or diesel price per gallon or liter at the pump.

Compute the optimal bedtime or wake time based on 90-minute sleep cycles so you wake between cycles feeling refreshed — enter target wake or bed time.

Estimate cubic yards and 60/80 lb bags of concrete needed for a slab, footing, wall, column, or stairs from length, width, and thickness measurements.