Math & Calculators

Work out crypto profit or loss from buy price, sell price, and quantity. Factor in exchange fees and see your ROI plus the break-even sell price.

Find the sale price from a discount percentage, or work backwards from two prices to figure out what percent off you actually got.

Compute fuel economy in MPG (US/UK), km/L, and L/100km, plus trip cost and cost-per-mile.

Convert between hourly wage and annual salary in either direction, with weekly, bi-weekly, and monthly breakdowns.

Project how much purchasing power you lose holding cash, or how much the same item will cost in N years at any annual inflation rate.

Estimate your real monthly mortgage payment, principal, interest, taxes, insurance, and PMI all in one number.

Compute total return and annualized return (CAGR) on any investment from initial capital, final value, and holding period.

Add tax to a price or pull tax out of a total. Works with any rate from 0% to 30%, with a quick reference for common US cities.

US federal income tax estimator using 2024 brackets, single, married joint, head of household, with standard or itemized deduction.

Add up your weekly hours from start/end times and break length, with overnight shift support and total-pay computation.

Split a restaurant bill across any group size with the tip included, quick tip presets, optional round-up so nobody gets stuck with the awkward $0.37.

Model dollar-cost averaging. Enter a fixed amount per period, the number of buys or a price list, and a current price to see units, cost basis, and profit.

Work out what each appliance costs to run. Enter watts, hours, and your kWh rate to see cost per day, month, and year, then total every device.

Log expenses by date, category, and amount. See per-category totals, an overall total, and export everything to CSV. Saved in your browser.

Estimate what a drive will cost in gas or diesel. Enter trip distance, your car's efficiency, and the pump price to get fuel needed and total cost.

Build a clean invoice with line items, tax, and an optional discount. Live preview updates as you type, then print straight to PDF.

Estimate the liquidation price of a leveraged long or short from entry price, leverage, side, and maintenance margin rate.

Set your selling price from cost and a markup percent, or work backward from cost and price to find the markup and the profit margin behind it.

Find the percent increase or decrease between two numbers, or grow and shrink any value by a percentage you choose. Both directions, instant results.

Enter revenue and cost to get your gross profit, profit margin percent, and the matching markup. See how much of every sale you actually keep.

Project your retirement nest egg from your age, savings, monthly contributions, and expected return.

Enter a wage in any period and see the hourly, daily, weekly, bi-weekly, monthly, and annual equivalents at once. Adjust hours and weeks worked.

Figure out how long until you hit a savings goal, or how much to set aside each month to reach it by a target date.

Work out simple interest from a principal, annual rate, and a term in years or months. See the interest earned and the total at the end, no compounding.

Add VAT to a net price or strip it out of a gross total. Shows net, VAT amount, and gross side by side, with common rate presets.

Calculate compound interest with year-by-year breakdown

Calculate monthly payments, total interest, and view amortization schedule

Calculate tip amount, total bill, and per-person split

Get your daily calorie target, BMR, TDEE, and macros, based on age, weight, height, activity, and whether you're cutting, maintaining, or bulking.

Calculate your pregnancy due date from last period, conception, or IVF transfer, with current week and trimester.

Estimate body fat percentage using the US Navy circumference method, needs only a tape measure, no calipers or DEXA scan.

A guided breathing pacer with a circle that grows and shrinks through inhale, hold, exhale, hold. Box 4-4-4-4, 4-7-8, or your own counts.

A 20-20-20 rule timer that nudges you every 20 minutes to look 20 feet away for 20 seconds. Start, pause, reset, with a chime and desktop alert.

Find your training heart rate zones from age. See max HR and five BPM zones, with an optional Karvonen mode that uses your resting heart rate.

Measure your reaction time in milliseconds. Click the instant the box turns green, run multiple trials, and see your best, average, and last score.

Estimate ideal body weight by the Devine, Robinson, Miller, and Hamwi formulas, with the healthy BMI weight range for your height.

Turn a daily calorie target into grams of protein, carbs, and fat. Pick a goal and split, or estimate your calories from age, weight, height, and activity.

Pick a wake-up time and get the best bedtimes, or pick a bedtime and get the best alarms. Built around 90-minute sleep cycles.

Estimate your daily water intake from body weight, activity, and climate. See the result in liters, US cups, and fluid ounces.

Calculate your Body Mass Index with metric or imperial units

Compute pixel dimensions for any aspect ratio, give width, get height (or vice versa). 7 common ratio presets.

Compute radius, diameter, circumference, and area from any one, pick which value you have, get the other three instantly.

Solve a right triangle for any side, hypotenuse from two legs, or one leg from the other and the hypotenuse.

From two points, get slope, distance, angle, line equation, and midpoint, all the standard line-geometry outputs in one shot.

Compute radius, diameter, surface area, and volume of a sphere from any one, pick what you have, get the other three.

Compute area (Heron's formula), perimeter, all three angles, and three altitudes for any triangle from its three side lengths.

Convert between units of length, weight, temperature, area, volume, speed, pressure, and energy

Convert between 35+ world currencies with sample exchange rates

Convert any number to its English word representation

Convert between decimal numbers and Roman numerals bidirectionally

Convert between Celsius, Fahrenheit, and Kelvin instantly

Full-featured scientific calculator with trigonometry, logarithms, exponents and more

Calculate percentages, percentage of a number, and percentage change

Solve proportions and simplify ratios with step-by-step results

Calculate your exact age in years, months, days with zodiac sign and birthday countdown

Calculate the exact difference between two dates in multiple units

Live countdown to any date with days, hours, minutes, and seconds

Generate Fibonacci sequences and check if numbers are Fibonacci

Calculate Greatest Common Divisor and Least Common Multiple with steps

Check if a number is prime, find primes in range, and factorize numbers

Add your courses, pick letter grades, set credit hours, get your GPA on the 4.0 scale. Adds and removes rows as you go.

Work out your weighted course grade from any number of assignments, or find the exact final exam score you need to hit a target.

Solve for running pace, finish time, or distance, switch between km and miles, with one-click presets for 5K, 10K, half, and full marathon.

Estimate your 1RM from a heavier set using the Epley and Brzycki formulas, plus a full table of training percentages and rep ranges.

Convert dog age to human equivalent (or back) using the size-aware AVMA formula instead of the old "× 7" myth.

Plot functions like x^2, sin(x), or 1/x on an interactive graph. Pan by dragging, zoom with the wheel, and overlay several functions in different colors.

A fun love compatibility calculator. Enter two names and get a playful match percentage with a cheeky verdict. Same names always give the same score.

Work out the time between two clock times, or add and subtract hours and minutes from a time. Handles crossing midnight and shows hours, minutes, and decimals.

Count working days between two dates, automatically excluding weekends and any holidays you list.

Perform binary arithmetic and bitwise operations with visual bit display

Solve linear equations, quadratic equations, and systems of two linear equations

Add, subtract, multiply matrices and find determinant, transpose, inverse

Calculate mean, median, mode, standard deviation, variance, quartiles and more