Tools

Choose a formula, enter what you know, leave the unknown blank — solved instantly with the rearranged equation.

Solve linear, quadratic, and simultaneous equations with step-by-step solutions and interactive graphs

Plot mathematical functions on an interactive canvas with zoom, pan, and multi-function overlay

Eight calculation modes in one tool: percent of, percent change, discount, tax, find the whole, and more — with instant work shown and visual charts.

Convert between standard, scientific, engineering and E-notation, round to significant figures, and count sig figs digit by digit.

Convert numbers to Roman numerals and Roman numerals back to numbers, instantly and accurately (1-3999).

Add, subtract, multiply, transpose, invert and find the determinant, rank and trace of matrices online

Differentiate any function step by step, evaluate f'(a), and see f and f' graphed together

Compute definite integrals numerically and see the signed area under the curve

Evaluate lim x→a f(x) numerically and visualize the approach from both sides with a table and graph

How big is that number, really? Understand it intuitively as 'how many' of everyday objects.

Type a formula to get its molar mass, element-by-element breakdown, and mole–gram–particle conversions.

Enter speed, angle and gravity, then watch the parabola fly. Range, peak height and flight time are computed instantly.

Play any frequency from 20 Hz to 20 kHz, then take the high-frequency hearing test to estimate your hearing age - all in your browser

Decode color bands into ohms or turn a resistance back into color bands, with a realistic resistor drawing

Decode a capacitor code like 104 into a capacitance, or turn a value back into its 3-digit code, with a realistic capacitor drawing

Compute V, I, R and P from any two values, size a voltage divider, or find the right series resistor for an LED

Convert power levels (dBm/dBW ⇄ W), compute dB ratios for power and voltage, and cascade gain in decibels

Estimate battery runtime from capacity and load, with real-world derating and Peukert's law for lead-acid

Add as many resistors or capacitors as you like, choose series or parallel, and get the combined value instantly

Calculate wire voltage drop, end voltage and power loss from current, length, gauge and material

Find the current-limiting resistor for one or more series LEDs from supply voltage, forward voltage and current

Convert American Wire Gauge to diameter, cross-section area, kcmil and resistance — and reverse-look up the nearest AWG

Convert between binary, octal, decimal, and hexadecimal with real-time bit pattern visualization

Convert between text and ASCII/Unicode codes with encoding tools

Test regular expressions with real-time match highlighting and capture group display

Encode and decode Base64 with full UTF-8 support

Percent-encode and decode text for safe use in URLs

AND, OR, XOR, NOT and bit shifts on 32-bit integers, with a live bit-by-bit visualization

Beautify, minify and validate JSON instantly in your browser

Compute MD5 and SHA hashes from text right in your browser

Cryptographically strong random integers and decimals, with unique-draw mode and handy presets

Generate cryptographically random UUID v4 / GUID values in bulk and copy them with one click

Create QR codes for links, Wi-Fi, contacts, email, phone and SMS, then download as PNG or SVG

Paste a JSON Web Token and instantly decode its header and payload — entirely in your browser, nothing is uploaded

Convert CSV to JSON and JSON to CSV in your browser

Create strong, truly random passwords in your browser with adjustable length, character sets and a live strength meter

Calculate the network and broadcast address, host range, subnet mask and CIDR for any IPv4 address and prefix - right in your browser

Paste or type your text and instantly see words, characters, sentences, reading time and more

Type or paste text and instantly get every common letter case, ready to copy

Generate placeholder text by paragraphs, sentences or words and copy it with one click

Translate text to Morse code and Morse code back to text, instantly and in your browser

Compare two blocks of text and instantly see added, removed and unchanged lines side by side

Convert between RGB, HEX, HSL, HSV, and CMYK with visual color picker and contrast checker

Calculate width, height, or aspect ratio for video, images and screens — keep 16:9, 4:3, 21:9 and more perfectly proportional.

Check text and background color contrast against WCAG 2.1 AA and AAA — instantly see the contrast ratio with a live preview and pass/fail badges.

Design beautiful linear, radial and conic CSS gradients with a live preview and copy the code in one click

Convert between Unix epoch time and human-readable dates

Stopwatch, countdown timer, and a live countdown to any date — all in one place

Add up daily and weekly work hours from clock-in and clock-out times, with automatic overtime and an optional pay estimate

Sunrise, sunset, twilight, golden hour and the moon phase for any place and date

Find the working-hours overlap across cities at a glance and pick a time that works for everyone

Create custom printable paper templates with live preview and instant PDF download

Convert between 30 world currencies with up-to-date exchange rates

Paste your ingredient list, set the servings, and get perfectly scaled amounts in fractions or decimals

Convert US, UK, EU and Japanese (cm) shoe sizes for men and women in one tap

Convert S/M/L and US, UK, EU and Japanese clothing sizes for women and men in one tap

Convert cups, tablespoons and spoons to grams and ounces — ingredient by ingredient, because flour and sugar don't weigh the same

Calculate the weight of steel, aluminum, copper and other metals — for bars, plates, pipes, tubes and angles, from real material densities

Add, subtract, multiply and divide feet, inches and fractions — then convert to decimal inches, feet, mm, cm and metres