Math & Calc Tools

Free online math calculators — percentage calculator, BMI calculator, tip and bill split, temperature converter, age calculator, and more. Instant results.

43 tools

Trig Calculator

All six trig functions in degrees, radians or gradians, with exact surd values, a unit circle, and honest undefined answers where tangent blows up.

Log Calculator

Compute a logarithm in any base, or solve for the base or argument, with change-of-base shown and the same log restated in base 10, e and 2.

% Calculator

Calculate percentages, percentage increase and decrease, and what percent one number is of another. Instant answers for discounts and grades.

BMI Calculator

Calculate your Body Mass Index (BMI) in metric or imperial units and see your health category instantly. Free, private, no sign-up required.

Tip Calculator

Calculate tip amounts and split bills between any number of people. Quick tip buttons, custom percentage, and per-person breakdown.

Temperature

Convert temperatures between Celsius, Fahrenheit, Kelvin, Rankine, and Delisle instantly. Common reference points included.

Age Calculator

Calculate your exact age in years, months, days, hours, and minutes from your date of birth. Shows total counts and next birthday countdown.

Loan Calculator

Calculate your monthly loan payment (EMI), total interest, and payoff date. Includes a full amortization schedule and an extra-payment savings breakdown.

Fraction Calculator

Add, subtract, multiply, divide and reduce fractions with the working shown at every step, plus mixed number, exact decimal and percent forms.

Quadratic Solver

Solve ax² + bx + c = 0 for exact radical roots, the discriminant, the vertex and a sketch of the parabola, with every line of working shown.

% Change Calculator

Calculate percentage increase, decrease, new value after a % change, or reverse-solve for the original. Four modes, instant results, no sign-up.

Ratio Calculator

Simplify ratios to lowest terms, solve proportions for the unknown X, or scale a ratio by any factor. Step-by-step working shown for each mode.

Scientific Calculator

Solve trig, log, power and factorial expressions with a full scientific keypad, DEG/RAD modes, memory keys, and calculation history. No eval() used.

Rounding Calculator

Round any number to N decimal places or N significant figures under 4 rounding modes, including banker's rounding. Exact decimal math, no float errors.

Pythagorean Theorem

Solve for a missing side or verify a right triangle from any two sides, with angles, area, perimeter and a squares-on-each-side diagram.

Area Calculator

Calculate area for rectangle, circle, triangle, trapezoid, or parallelogram — with the formula shown and a live labelled diagram. Free.

Volume Calculator

Volume, surface area and litre capacity for a cube, box, sphere, cylinder, cone or square pyramid, with the working shown under every answer.

Also in Math & Calc

Tools from other categories tagged with Math & Calc

Wei/ETH Converter

Convert between all 10 Ethereum denominations — Wei, Gwei, Szabo, Finney, ETH and more — with BigInt precision and instant copy for every result.

Gas Fee Calculator

Calculate Ethereum gas fees in ETH and USD. Supports EIP-1559 (base fee + tip) and legacy gas price. Six transaction type presets included.

Satoshi/BTC

Convert between Satoshi, Bit, mBTC and BTC with BigInt precision. No floating-point rounding at the satoshi level, no price feed, no network call.

Token Supply

Convert ERC-20 token amounts to the base-unit integer a contract call takes and back, and measure any holding against total supply. BigInt-exact.

Vesting Planner

Turn an allocation, cliff and vesting period into a dated unlock schedule with a cumulative curve and CSV export. Handles both cliff conventions.

APY/APR Converter

Convert APY to APR or APR to APY across 8 compounding frequencies. Shows the formula, result, and a full comparison table. Includes continuous compounding.

Staking Rewards

Project staked crypto growth over any period at a given APR, with simple or compounding payout. See total rewards, effective APY and a balance timeline.

CLV Calculator

Work out customer lifetime value three ways, with the LTV to CAC ratio and payback month, and see why zero churn breaks the usual formula.

A/B Significance

Run a two-proportion z-test on your A/B test results and get a real p-value, not just a percentage. Fully client-side, no data ever leaves your device.

CTR Calculator

Calculate click-through rate from clicks and impressions, set a target CTR to see the click gap, and compare against common channel benchmarks. Offline.

CPM Calculator

Solve for CPM, impressions or ad spend from the other two, with a target-CPM gap, cost per impression and common channel benchmarks. No ad-platform login.

Matrix Calculator

Add, subtract, multiply, transpose, and find the determinant or inverse of a 2x2 or 3x3 matrix. No data ever leaves your device.

Fibonacci Generator

Generate the Fibonacci sequence up to F(200) with exact BigInt precision. Shows golden-ratio convergence, a visual bar chart, and copy as CSV or lines.

Date Difference

Get the exact calendar difference between two dates in years, months and days, plus total days, weeks, hours and minutes.

Date Add / Subtract

Add or subtract years, months, weeks, days, hours and minutes from any date. Month-end clamping, ISO week number and a copyable ISO 8601 stamp.

Number to Words

Convert any number to English words, ordinal form, or currency text. Supports integers, decimals, negatives up to 999 Trillion.

Roman Numerals

Convert integers (1–3999) to Roman numerals and decode Roman numerals back to Arabic numbers. Full reference table included.

Timestamp

Convert Unix timestamps to human-readable dates and convert dates back to Unix time. Live clock with ISO 8601, UTC, and local formats.

Prime Factors

Input N to instantly view prime factorization, total divisors, Euler totient, and full sorted divisors list with prime highlighting.

Modulo Calc

Compute modular inverse, fast power modulo, and nCr mod p using BigInt precision. One-click C++ snippet output for each operation.

Convex Hull

Click the canvas to place coordinate points. Renders the enclosing convex hull polygon live using Andrew's monotone chain. Outputs C++ points vector.

Combinatorics

Calculate nCr, nPr, factorials, Catalan numbers and Stirling numbers using exact BigInt arithmetic. Step-by-step working shown for every result.

Extended GCD

Compute GCD, LCM, and Bezout coefficients x, y for ax+by=gcd with a full Euclidean step trace and modular inverse — BigInt-exact up to 10¹⁸.

Sieve Visualizer

Animate the Sieve of Eratosthenes step by step on a colour-coded grid. Enter any limit up to 500, step through each elimination, and copy the prime list.

Binary Search

Step through binary search on your own sorted array. Highlights lo, hi and mid at each probe. Play, pause or step manually. O(log n) worst-case shown.

Prime Checker

Check whether any positive integer is prime, with the full prime factorisation when it is not. Trial division to ⌈√n⌉ — deterministic and exact.

Why These Tools

On a long loan at an ordinary rate, most of what you pay in the early years is interest rather than principal, and Loan Calculator draws that split month by month instead of handing you a single monthly figure and stopping. The others here are smaller and get opened more often. Percentage Calculator covers increase, decrease and what-percent-of without making you pick a mode first. Fraction Calculator & Simplifier reduces every result by its greatest common divisor. Age Calculator counts in days and hours as well as years, which is the part people usually come for. A salary figure or a date of birth stays on the machine you typed it into.