Math & Numbers

Evaluate mathematical expressions safely — supports arithmetic, trig, logs, sqrt, and more.

Check if a number is prime, find primes up to N, prime factorization, and nearest prime finder.

Calculate percentages, percent change, and percent increase/decrease instantly.

Compute mean, median, mode, variance, standard deviation, and quartiles from a list of numbers.

A full scientific calculator with trig, logs, powers, and memory functions.

Generate random integers or decimals within a range, with optional uniqueness and precision controls.

Add, subtract, multiply, transpose, and invert matrices with determinant calculation.

Solve right triangles — find the missing side, area, perimeter, and angles.

Calculate Body Mass Index from height and weight, with metric and imperial units.

Add, subtract, multiply, and divide fractions, and simplify to lowest terms.

Convert between Arabic numbers (1-3999) and Roman numerals, with canonical-form validation in both directions.

Perform AND, OR, XOR, NOT, and shift operations on two numbers, with binary, hex, and decimal views.

Calculate your monthly mortgage or loan payment, total interest, and full amortization schedule — with optional extra monthly payments.

Perform arithmetic (add, subtract, multiply, divide) and bitwise operations (AND, OR, XOR, NOT, shifts) on binary numbers, with live decimal/hex cross-reference.

Convert a data size between bytes, KB/MB/GB/TB and their binary (KiB/MiB/GiB/TiB) equivalents, showing both the decimal (SI) and binary (IEC) systems side by side.

Project how an investment or savings balance grows over time with compound interest and optional regular monthly contributions, with a year-by-year breakdown.

Convert geographic coordinates between Decimal Degrees and Degrees-Minutes-Seconds (DMS) notation, in both directions.

Calculate the great-circle distance and initial compass bearing between two latitude/longitude points using the Haversine formula.

Calculate the exact probability of every possible sum when rolling any number of dice with any number of sides, using full combinatorial math rather than simulation.

Estimate your daily calorie needs using the Mifflin-St Jeor equation, based on your age, sex, height, weight, and activity level.

Convert between Celsius, Fahrenheit, and Kelvin instantly — edit any field and the other two update automatically.

Generate the Fibonacci sequence up to any number of terms with exact BigInt precision, plus the golden-ratio approximation of the last two terms.

Calculate the greatest common divisor and least common multiple of two or more integers, with a visible step-by-step Euclidean algorithm trace.

Solve ax² + bx + c = 0 using the quadratic formula, showing the discriminant, both roots (real or complex), and the parabola's vertex.

Calculate nPr (permutations) and nCr (combinations) for a given n and r, with exact BigInt precision and the formula shown step-by-step.

Calculate total hours worked from clock-in/clock-out times across multiple days, with an optional unpaid break deducted per day, plus a decimal-hours total for payroll.

Calculate a discounted price from an original price and percent off, with support for two sequential ("stacked") discounts and the effective combined discount rate.

Add sales tax to a pre-tax price, or reverse-calculate the pre-tax price and tax amount from a tax-inclusive total, given a tax rate.

Calculate the selling price and profit amount from a cost and markup percentage, where markup is expressed as a percentage of cost (distinct from profit margin, a percentage of selling price).

Calculate profit margin percentage from cost and selling price, or find the selling price needed to hit a target margin — margin is always a percentage of selling price, distinct from markup (a percentage of cost).

Calculate the break-even point — in units and revenue — from fixed costs, price per unit, and variable cost per unit, the point where total revenue equals total costs.

Calculate your grade point average by entering letter grades and credit hours for each course, on either a 4.0 or 5.0 grading scale.

Estimate how much fuel a trip will use and what it will cost, from trip distance, vehicle fuel efficiency (MPG, L/100km, or km/L), and fuel price.

Estimate body fat percentage using the U.S. Navy circumference method — neck, waist (and hip for women), and height measurements, no calipers or scan required.

Convert between bytes, KB/MB/GB/TB (decimal, 1000-based) or KiB/MiB/GiB/TiB (binary, 1024-based), showing all units side by side at once.

Calculate return on investment (ROI) and annualized return (CAGR) from an initial investment, final value, and holding period.

Project the future value of your retirement savings from current balance, monthly contributions, years until retirement, and an expected annual return, compounded monthly.

Enter a partially-filled 9x9 Sudoku grid and instantly solve it using a backtracking algorithm — or load a classic example puzzle.

Calculate the minimum hourly rate you need to charge based on your target take-home income, business expenses, estimated tax rate, and billable hours.

Estimate total fencing project cost from linear footage, price per foot (material + installation), and any gates.

Track a personalized list of assets and liabilities and calculate your total net worth.

Calculate the monthly contribution needed to reach a specific savings goal by a target date, accounting for current savings and interest earned.

Convert an hourly wage to an equivalent annual salary, or an annual salary back to an hourly rate, based on hours per week and working weeks per year.

Calculate regular pay, overtime pay, and total weekly pay from an hourly rate, overtime multiplier, and hours worked past a weekly threshold.

Compare the debt snowball (smallest balance first) and debt avalanche (highest interest rate first) payoff strategies across multiple debts, with total months and interest paid.

Scale a list of recipe ingredients up or down for a different number of servings, automatically recalculating each quantity including fractions and mixed numbers.

Estimate ideal body weight from height and sex using four classic medical formulas: Devine, Robinson, Miller, and Hamwi.

Calculate your waist-to-hip ratio and see the corresponding WHO health-risk category based on your sex.

Calculate your target heart rate training zones from age and resting heart rate using the Karvonen formula.

Calculate the cubic yards of concrete and number of 80 lb pre-mix bags needed for a slab from its length, width, and thickness.

Estimate how many gallons of paint and what total cost you'll need based on wall area, number of coats, and coverage per gallon.

Calculate how many boxes of flooring (tile, laminate, hardwood, or vinyl) you need from room dimensions, a waste/cut allowance, and coverage per box.

Estimate your one-repetition maximum (1RM) for a lift using the Epley and Brzycki formulas, plus a percentage-based training table for programming lighter sets.

Calculate your running pace and speed from distance and time, plus predicted finish times for 5K, 10K, half marathon, and marathon at that same pace.

Calculate how many cubic yards and bags of mulch you need for a garden bed based on area and desired depth.

Calculate your overall course grade from multiple weighted categories (homework, quizzes, exams) — add, remove, and adjust categories and scores freely.

Calculate cubic yards and tons of gravel needed for a driveway, path, or base layer from area, depth, and material density.

Estimate your VO2 max (aerobic fitness) from the Cooper 12-minute run test distance, with a fitness category rating.

Estimate your recommended daily water intake in ounces and liters from body weight and daily exercise minutes.

Calculate ideal bedtimes or wake-up times based on 90-minute sleep cycles, so you wake up at the end of a cycle instead of mid-cycle.

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

Calculate the number of risers, actual riser height, number of treads, and total run for a staircase from total rise and target riser height.

Calculate simple interest and total repayment amount from principal, annual interest rate, and time in years — using I = P × r × t.

Calculate daily calorie needs (TDEE) and macronutrient targets (protein, carbs, fat in grams) from body stats, activity level, and a chosen macro split.

Calculate the daily, monthly, and yearly running cost of any appliance from its wattage, daily usage hours, and your electricity rate.

Generate a multiplication table for any number up to 10, 12, or 20 — a simple study aid for learning times tables.

Calculate roof surface area, roofing squares, and shingle bundles needed from footprint dimensions and roof pitch, including a waste factor.

Estimate your vehicle's value loss over time using a compounding annual depreciation rate, with a full year-by-year value breakdown.

Compare two products by their true per-unit cost (price ÷ quantity) to find which is actually the better deal, regardless of package size.

Estimate drywall sheets, screws, and joint compound needed for a room from its dimensions and sheet size, including a waste allowance.

Calculate the daily, monthly, and yearly fuel cost of your commute from one-way distance, vehicle MPG, gas price, and commute days per week.

Estimate how many years it takes for solar panel electricity savings to pay back the system cost, accounting for rising electricity rates and maintenance.

Estimate your Texas Hold'em pre-flop win probability against 1-8 opponents using a 5,000-hand Monte Carlo simulation of your two hole cards.

Calculate your recommended daily protein intake in grams based on body weight and activity/training goal, from sedentary maintenance to muscle-building or cutting.

Estimate how many additional inches of insulation and how many bags you need to reach a target R-value, based on your attic area and current insulation level.

Estimate blood alcohol concentration from body weight, biological sex, standard drinks consumed, and hours elapsed, using the Widmark formula.