All tools

Percentage Calculator

Calculate percentages three ways: find a percentage of a number, find what percent one number is of another, or find the total when you know a part and a percentage.

Percentage Change

Find how much a value increased or decreased as a percentage of the original amount.

Percent Error

Measure how far an experimental value sits from an accepted or theoretical value, as a percentage.

Discount Calculator

Work out the amount saved and the sale price from an original price and a percent off.

Markup Calculator

Add a markup percent to cost to get the markup amount and selling price.

Margin Calculator

From cost and selling price, see profit, margin percent and markup percent.

Average Calculator

Find the arithmetic mean, count and sum of a list of numbers pasted or typed in your browser.

Ratio Calculator

Simplify two numbers to lowest terms and see the decimal relationship A ÷ B.

Fraction to Decimal

Convert a numerator and denominator into a decimal and a percentage.

Fraction Calculator

Add, subtract, multiply or divide two fractions and see the simplified result, mixed number and decimal.

Scientific Calculator

Evaluate expressions with powers, roots, logs, factorials and trigonometry in degrees or radians.

Exponent Calculator

Raise a base to a power, including negative and fractional exponents, with overflow rejected.

Root Calculator

Find the nth root of a number, including odd roots of negatives such as the cube root of −8.

Log Calculator

Compute a logarithm in base 10, base e, base 2, or any custom positive base other than 1.

Rounding Calculator

Round a number to a chosen number of decimal places, or to the nearest ten, hundred or thousand.

LCM Calculator

Find the least common multiple of two or more integers pasted as a list.

GCF Calculator

Find the greatest common factor (GCD) of two or more integers pasted as a list.

Factor Calculator

List every positive factor of an integer and see its prime factorization.

Quadratic Formula

Solve ax² + bx + c = 0 for real roots, and see the discriminant and vertex.

Scientific Notation

Convert a decimal to normalized scientific notation, or turn a coefficient and exponent back into a number.

Random Number Generator

Draw one or more random integers or decimals between a minimum and a maximum in your browser.

Binary Calculator

Convert between binary and decimal, or add, subtract, multiply and divide whole binary numbers.

Hex Calculator

Convert between hexadecimal and decimal, or add, subtract, multiply and divide whole hex numbers.

Triangle Calculator

Find a triangle’s area, perimeter and angles from three sides, or the area from base and height or SAS.

Volume Calculator

Find the volume of a cube, box, sphere, cylinder, cone or rectangular pyramid in unit³.

Slope Calculator

Find the slope of a line from two points or from rise and run, plus the angle from the positive x-axis.

Area Calculator

Find the area of a square, rectangle, triangle, circle, trapezoid, parallelogram or ellipse.

Distance Calculator

Find the straight-line distance between two points in a plane or in 3-D space.

Circle Calculator

From radius, diameter or circumference, get the other two plus the area of a circle.

Surface Area

Find the total surface area of a cube, box, sphere, cylinder or cone, including slant height for a cone.

Pythagorean Theorem

Find the hypotenuse from two legs, or a missing leg from the hypotenuse and the other leg.

Right Triangle

From two legs, or a leg and the hypotenuse, get the third side, both acute angles, area and perimeter.

Standard Deviation

Paste a list of numbers and choose sample (n − 1) or population (n) standard deviation.

Number Sequence

Find the nth term and the sum of an arithmetic or geometric sequence.

Sample Size

Estimate how many observations a proportion survey needs for a chosen confidence level and margin of error.

Probability Calculator

Combine two event probabilities as independent, mutually exclusive, or overlapping, plus complements and “at least one”.

Statistics Calculator

Paste a list and get count, mean, median, mode, range, and both sample and population variance and SD.

Mean Median Mode Range

Paste a list of numbers to get the mean, median, mode and range in one place.

Permutations & Combinations

Compute P(n, r) when order matters and C(n, r) when it does not, for whole numbers n ≥ r ≥ 0.

Z-score Calculator

Convert a value to a z-score, or a z-score back to the original scale, given a mean and standard deviation.

Confidence Interval

Build a z-interval for a mean from x̄, a standard deviation, n and a confidence level.

BMI Calculator

Compute body mass index from height and weight using kg/m², with WHO adult categories.

Calorie Calculator

Estimate total daily energy expenditure as Mifflin-St Jeor BMR times an activity factor.

Body Fat Calculator

Estimate body-fat percentage from the U.S. Navy circumference (tape) method.

BMR Calculator

Estimate basal metabolic rate with the Mifflin-St Jeor equation from sex, age, height and weight.

Ideal Weight

Estimate Devine (1974) ideal body weight from height and the male or female equation.

Pace Calculator

Turn a distance and a finish time into minutes per kilometre or per mile.

Army Body Fat

Apply the U.S. Army AR 600-9 / DoD tape equations — the same circumference formulas as the Navy method.

Lean Body Mass

Estimate lean body mass with the Boer (1984) equations from sex, height and weight.

Healthy Weight

Show the adult weight range that corresponds to WHO BMI 18.5–24.9 for a given height.

Calories Burned

Estimate activity calories as MET × body weight (kg) × hours, using common Compendium-style MET values.

One Rep Max

Estimate a one-rep max from a submaximal set using Epley (primary) and Brzycki (check).

Target Heart Rate

Estimate HRmax with Tanaka (208 − 0.7×age) and five training zones, optionally using Karvonen if you enter resting HR.

Days From Today

Find the exact calendar date a set number of days before or after a chosen start date.

Days Ago

Find the calendar date a given number of days before today, or before any start date you choose.

Days Between Dates

Count how many calendar days separate two dates, including the week-and-remainder breakdown.

Weeks Between Dates

See how many full weeks (and leftover days) separate two calendar dates.

Months Between Dates

Count whole calendar months between two dates, plus leftover days and a years-and-months split.

Age Calculator

Calculate age in years, months and days from a birth date to today or to any target date.

Business Days

Count weekdays between two dates, excluding Saturday and Sunday. Public holidays are not removed.

Day of Week

Look up which weekday a calendar date falls on, without time-zone shifts.

Birthday Countdown

See the next birthday date, weekday and how many days remain from today.

Time Duration

Find hours and minutes between two clock times, including overnight spans that cross midnight.

CM to Inches

Convert centimeters to inches instantly using the exact 2.54 cm/inch definition.

Inches to CM

Convert inches to centimeters using the exact international definition of the inch.

Feet to Meters

Convert feet to metres using the exact international foot of 0.3048 m.

Meters to Feet

Convert metres to feet by dividing by the exact 0.3048 m international foot.

MM to Inches

Convert millimetres to inches using 1 inch = 25.4 mm exactly.

Inches to MM

Convert inches to millimetres by multiplying by the exact 25.4 mm inch.

KG to LBS

Convert kilograms to pounds using the exact international avoirdupois pound of 0.45359237 kg.

LBS to KG

Convert pounds to kilograms with the exact 0.45359237 kg per avoirdupois pound definition.

Grams to Ounces

Convert grams to avoirdupois ounces using 1 oz = 28.349523125 g exactly.

Ounces to Grams

Convert avoirdupois ounces to grams using 1 oz = 28.349523125 g exactly.

KM to Miles

Convert kilometres to international miles using the exact 1 609.344 metre mile.

Miles to KM

Convert international miles to kilometres. One mile is exactly 1.609344 km.

Liters to US Gallons

Convert litres to US liquid gallons (3.785411784 L). Not the Imperial gallon.

US Gallons to Liters

Convert US liquid gallons to litres using 1 US gal = 3.785411784 L exactly.

ML to US Fluid Ounces

Convert millilitres to US fluid ounces (29.5735295625 mL). Not Imperial fl oz.

HP to kW

Convert mechanical horsepower to kilowatts (1 hp = 0.7456998716 kW).

kW to HP

Convert kilowatts to mechanical horsepower using 1 hp = 0.7456998716 kW.

C to F

Convert Celsius to Fahrenheit with the exact formula F = C × 9/5 + 32.

F to C

Convert Fahrenheit to Celsius with C = (F − 32) × 5/9. 32°F is 0°C; 212°F is 100°C.

Electricity Cost

Estimate energy (kWh) and cost from power in watts or kW, hours of use and price per kWh.

Appliance Energy Cost

Estimate daily and monthly kWh and cost for an appliance from watts, hours per day, days per month and price.

EV Charging Cost

Estimate battery energy added, grid energy and charging cost from capacity, start/target %, price and efficiency.

EV Charging Time

Estimate ideal charging time from battery size, start/target % and charger power. Real sessions are often slower.

kWh Cost

Multiply kilowatt-hours by your electricity price to get a total cost.

Fuel Cost

Estimate litres used, trip fuel cost and cost per kilometre from distance, L/100 km and price per litre.

L/100km to MPG

Convert litres per 100 km to miles per gallon, with a clear US vs Imperial gallon choice.

MPG to L/100km

Convert miles per gallon to litres per 100 km, choosing US or Imperial gallons explicitly.

Cost Per Kilometer

Divide a total cost by distance to see cost per kilometre.

Road Trip Cost

Estimate fuel, optional tolls and parking, and a total trip cost from distance, L/100 km and fuel price.

Word Counter

Count words, characters, sentences and paragraphs in your browser. Text never leaves this page.

Character Counter

Count characters, characters without spaces and words locally in your browser. Text never leaves this page.

Unix Timestamp

Convert Unix seconds to UTC and local date/time, or a date/time back to Unix seconds. Millisecond values are detected.

QR Code Generator

Create static QR codes for URLs, Wi-Fi, text, email, SMS and contacts. Download PNG or SVG in your browser — no signup.

Password Generator

Create a strong random password in your browser. No signup, and the password is never stored or sent to analytics.

UUID Generator

Generate one or many RFC 4122 UUID v4 values in your browser. Copy or download as TXT.

Base64 Encoder / Decoder

Encode and decode Base64 in your browser with proper UTF-8 support, including Unicode and emoji.

URL Encoder / Decoder

Percent-encode or decode URL components in your browser with encodeURIComponent and decodeURIComponent.

JSON Formatter

Pretty-print, minify or validate JSON in your browser. Parse errors show an approximate line and column.

Hash Generator

Hash text with SHA-256, SHA-384 or SHA-512 in your browser. Output is lowercase hex. Hashing is not encryption.

Lorem Ipsum Generator

Generate placeholder paragraphs, sentences or words in your browser. Optionally start with the classic opening line.

Text Case Converter

Convert text to lowercase, UPPERCASE, Title Case, Sentence case, camelCase, PascalCase, snake_case or kebab-case.

Slug Generator

Turn a title into a URL-friendly slug. Latin accents including Swedish å, ä and ö become ASCII letters.

Color Converter

Convert colors between HEX, RGB and HSL with a live preview. Accepts #RGB and #RRGGBB.