Free, no-nonsense calculators
Quick, free, no-nonsense calculators — percentages, loans, dates, conversions and more. Everything runs in your browser. 48 tools and counting.
Loan, mortgage, interest, salary and tax calculators — work out payments, rates and totals in seconds.
Car Loan Calculator
Free car loan calculator — work out the monthly payment, total cost and total interest on an auto loan from the price, interest rate, and term in years. Runs in your browser.
Compound Interest Calculator
Free compound interest calculator — see what a starting balance grows to over time at a given rate, with annual, quarterly, monthly or daily compounding. Runs in your browser, no sign-up.
Discount Calculator
Free discount and sale price calculator — find the final price and the amount saved on any percentage-off deal. Type the original price and the percent off. Works in your browser.
Hourly to Salary Calculator (annual, monthly, weekly)
Free hourly-to-salary calculator — type any rate (hourly, weekly, monthly or annual) and see the other three. Adjusts for hours per week and weeks worked per year.
Inflation Calculator (future value & buying power)
Free inflation calculator — project a value forward in time (future buying-power equivalent) or discount a future value back to today, at any inflation rate.
Mortgage Calculator
Free mortgage calculator — work out your monthly payment, total cost over the life of the loan, and total interest paid. Just enter the loan amount, interest rate and term. Runs in your browser, no sign-up.
Personal Loan Calculator
Free personal loan calculator — work out the fixed monthly payment, total cost, and total interest on an unsecured installment loan from amount, rate, and term in years. Runs in your browser.
Profit Margin & Markup Calculator
Free profit margin and markup calculator — go between cost, selling price, and margin or markup percent. Clears up the margin-vs-markup confusion.
ROI Calculator
Free return-on-investment (ROI) calculator — work out the profit and percent return between an initial amount and a final amount. Single-period ROI in your browser.
Savings Goal Calculator — How Much to Save Each Month
Free savings-goal calculator — set a target amount and a time horizon, get the monthly contribution you need at any interest rate. Accounts for an initial deposit.
Simple Interest Calculator
Free simple interest calculator — work out the interest and final balance on a principal at a given rate over time. Uses the I = P × r × t formula. Runs in your browser, no sign-up.
Tip Calculator
Free tip calculator with bill split — type in the bill, pick a tip percentage, and split the total between any number of people. Works in your browser, no sign-up.
BMI, calorie, body-fat and pregnancy calculators to help you track health and fitness numbers.
BMI Calculator
Free BMI calculator — type in weight and height to get your body mass index and the WHO weight category. Runs in your browser, no sign-up. Metric units (kg, cm).
Body Fat Percentage Calculator (US Navy method)
Free body fat percentage calculator using the US Navy formula — enter height, neck, waist (and hip for women) in metric or imperial, get the % and the category.
Daily Water Intake Calculator
Free daily water intake calculator — estimate how much water to drink each day from your body weight and activity level. Works in your browser.
Heart Rate Zones Calculator
Free max heart rate and training zones calculator. Enter your age (optionally with resting HR for Karvonen) and get the 5 cardio zones in bpm.
Ideal Weight Calculator
Free ideal body weight calculator using the Devine formula — the reference equation in clinical pharmacology. Metric units (kg, cm). Runs in your browser.
Macros Calculator (Protein, Carbs, Fat)
Free macronutrient calculator — split a daily calorie target into grams of protein, carbs and fat by your chosen percentages. Works in your browser.
Pregnancy Due Date Calculator
Free pregnancy due date and gestational age calculator (Naegele's rule). Type the first day of your last menstrual period and a reference date to see your estimated due date.
Running Pace Calculator
Free running pace calculator — find your pace from a finish time, or predict finish time from a target pace. Works for km and miles. Runs in your browser.
Sleep Cycle Calculator (bedtime & wakeup times)
Free sleep cycle calculator — pick a wakeup time or a bedtime and the calculator returns the best matching times based on 90-minute REM cycles.
TDEE & BMR Calculator
Free TDEE (Total Daily Energy Expenditure) and BMR calculator — uses the Mifflin-St Jeor equation, the formula clinical dietitians prefer. Metric units (kg, cm). Runs in your browser.
Practical day-to-day calculators: dates, tips, fuel cost, time math and more.
Add Days to a Date Calculator
Free "add days to date" calculator — pick a start date and a number of days (positive or negative) to find the resulting date. Handles leap years.
Age Calculator
Free age calculator — type a birthdate and a reference date and get exact age in years, months and days. Defaults to today. Runs in your browser.
Aspect Ratio Calculator
Free aspect ratio calculator — get the reduced ratio of a width × height, or resize a width or height while keeping a target ratio. Works in your browser.
Business Days Calculator (weekdays only, holidays optional)
Free business-days calculator — counts weekdays between two dates and subtracts holidays you list. Use for SLAs, deadlines, contract terms.
Days Between Dates Calculator
Free days between dates calculator — type two dates and get the exact number of calendar days between them. Works in your browser, no sign-up.
Days Until Calculator (countdown to any date)
Free days-until calculator — pick a future date and see how many days, weeks and remaining days until it. Works for past dates too ("passed N days ago").
Fuel Cost Calculator
Free fuel cost calculator — work out how much a trip will cost in fuel from distance (km), consumption (km/L), and price per litre. Runs in your browser.
Time Duration Calculator
Free time duration calculator — type a start time and end time and get the hours and minutes between them. Handles times that cross midnight. Works in your browser.
Unit Price Calculator
Free unit price calculator — divide price by quantity to find the cost per unit. Lets you compare grocery deals across different sizes. Runs in your browser.
Fast, accurate unit and measurement converters — length, weight, temperature, volume and beyond.
Area Converter
Free area converter between metric (mm², cm², m², ha, km²) and imperial (in², ft², yd², acre, mi²). Uses exact international definitions. Works in your browser.
Data Storage Converter (KB, MB, GB, TB, KiB, MiB…)
Free digital storage converter — bits, bytes, KB, MB, GB, TB, PB and the binary IEC versions (KiB, MiB, GiB, TiB). Clears up the 1000-vs-1024 confusion.
Length Converter
Free length / distance converter between metric (mm, cm, m, km) and imperial (in, ft, yd, mi) units. Uses the international definitions. Works in your browser.
Speed Converter
Free speed converter — km/h, mph, m/s, knots, ft/s and more. Uses exact conversion factors. Works in your browser.
Temperature Converter
Free temperature converter between Celsius (°C), Fahrenheit (°F) and Kelvin (K). Works in your browser, no sign-up.
Volume Converter
Free volume converter between metric (mL, L, m³) and US / UK customary (fl oz, cup, pint, quart, gallon). Includes US tablespoons and teaspoons. Runs in your browser.
Weight / Mass Converter
Free weight and mass converter between metric (mg, g, kg, t) and imperial (oz, lb) units. Uses the exact international avoirdupois definitions. Works in your browser.
Percentages, ratios, fractions and other everyday math worked out instantly.
Compound Rule of Three Calculator
Free compound rule of three calculator — solve a proportion problem driven by two supplementary variables (each direct or inverse). Works in your browser.
Final Grade Needed Calculator
Free "what do I need on the final?" calculator — enter your current grade, final exam weight and target overall to see the score required.
Fraction Calculator
Free fraction calculator — add, subtract, multiply or divide two fractions. The result is shown in lowest terms with the decimal value. Works in your browser.
LCM and GCD Calculator
Free LCM (least common multiple) and GCD (greatest common divisor) calculator — type a list of integers, get both at once. Works in your browser.
Mean, Median and Mode Calculator
Free mean, median and mode calculator — paste any list of numbers and get all three at once, plus a quick read on whether the data are skewed.
Percentage Calculator
Free percentage calculator — find X% of a number, work out what percent one number is of another, or calculate a percentage increase or decrease. Instant, works in your browser, no sign-up.
Quadratic Equation Solver
Free quadratic equation solver — enter a, b, c and get both roots using the quadratic formula (Bhaskara). Handles real, repeated and complex roots.
Roman Numerals Converter (number ↔ Roman, I–MMMCMXCIX)
Free Roman numerals converter — type a number to get the Roman form, or a Roman numeral to get the number. Validates subtractive notation (IV, IX, XL, XC, CD, CM).
Rule of Three Calculator
Free rule-of-three calculator (cross multiplication) — direct and inverse proportion. Enter three known values, get the fourth. Works in your browser.
Weighted Average Calculator
Free weighted average calculator — combine values with their weights in one step. Great for grades, GPAs and any weighted score. Works in your browser.