Calculators & Converters

Percentage Calculator The three classic percentage problems solved instantly: X% of Y, X is what % of Y, and % change. Rule of Three Calculator Solve direct and inverse proportions: enter three known values and get the fourth, with the math spelled out. Number Base Converter Convert numbers between binary, octal, decimal and hexadecimal — all four fields update as you type. Mean, Median & Mode Calculator Paste a list of numbers and get the mean, median, mode, range and totals in your browser. Standard Deviation Calculator Calculate sample and population standard deviation and variance, with every step shown. Sample Size Calculator Find how many answers a survey needs for a given confidence level and margin of error. Weighted Average Calculator Average values that carry different weights — and find the grade you need on the next test. LCM & GCD Calculator Find the least common multiple and the greatest common divisor of any list of whole numbers, step by step. Simple Interest Calculator Calculate simple interest and the final amount — or leave one field empty to find the principal, rate or time. Discount Calculator Work out the price after a discount, the percentage between two prices, and what stacked discounts really add up to. Factorial, Permutation & Combination Calculator Work out n!, arrangements, combinations and anagram counts exactly, with every step shown in your browser. Fraction Calculator & Simplifier Reduce any fraction to lowest terms and add, subtract, multiply or divide two fractions — with the GCD and the LCM shown. Fraction ↔ Decimal Converter Turn a fraction into a decimal — repeating period included — and any decimal back into an exact fraction. Scientific Notation Converter Convert any number to scientific and engineering notation, and back again, with significant figures counted. Prime Number Checker & Factorizer Check whether a number is prime, break it into prime factors, list every prime up to N and find the next one. Pythagorean Theorem Calculator Find the hypotenuse or a missing leg of a right triangle, with every step of the calculation shown. Area & Perimeter Calculator Area and perimeter of squares, rectangles, triangles, circles, trapezoids and rhombuses, with the formula applied to your numbers. Volume Calculator Volume of cubes, boxes, spheres, cylinders, cones and pyramids — plus surface area where it is direct — in your browser. Angle Converter Convert degrees, radians, gradians and degrees-minutes-seconds, with the sine, cosine and tangent of the angle. Multiplication Table Times table for any number from 1 to 100, a clickable 1-10 grid and a practice mode with a session score. Length & Distance Converter Convert millimetres, metres, kilometres, inches, feet, yards and miles all at once in your browser. Weight & Mass Converter Convert kilograms, grams, tonnes, pounds, ounces, stones and the Brazilian arroba in one table. Temperature Converter Convert Celsius, Fahrenheit and Kelvin with the exact formula shown for every conversion. Volume & Capacity Converter Convert litres, millilitres, cubic metres, gallons, cups, tablespoons and teaspoons at once. Area Converter (m², hectare, acre, alqueire) Convert m², km², hectare, are, ft², acre, square mile and the Brazilian alqueire — full equivalence table in your browser. Speed Converter (km/h, mph, m/s, knots, Mach) Convert km/h, mph, m/s, knots, ft/s and Mach with a full equivalence table — in your browser. Data Storage Converter (GB, GiB, MB, Mbps) Convert decimal and binary storage units plus bits and bytes — and finally see why a 1 TB drive shows up as 931 GB. Roman Numeral Converter Convert numbers to Roman numerals and back, with strict validation and a step-by-step breakdown. Paper Size Reference (A4, letter, DPI pixels) Search any paper size and get its dimensions in mm, cm and inches plus pixels at 72, 150, 300 and 600 DPI. Profit Margin & Markup Calculator Turn cost and price into profit margin, markup and profit in reais — or work backwards to the price you should charge. Product Pricing Calculator Find the sale price that covers your cost, taxes, fees and commission and still leaves the profit margin you want. Break-Even Point Calculator Find how many units you must sell each month to cover your fixed costs — and what revenue that adds up to. Contribution Margin Calculator See how much each sale leaves to pay the fixed costs, in reais and as a percentage of the price. Cooking Measurement Converter Convert cups, spoons, millilitres and fluid ounces in your browser — with the cup standard your recipe actually uses. Clothing Size Converter Type your body measurements and see the corresponding clothing size in BR, EU, US and UK — with the full chart on screen. Shoe Size Converter Measure your foot in centimetres and see the corresponding shoe size in BR, EU, UK, US and Mondopoint — with ISO 9407 references. Ring Size Converter Measure your finger circumference and see the corresponding ring size in BR (aro), ISO, US and UK — based on NBR 16058. Bra Size Converter Type your underbust and bust measurements and see the corresponding bra size in BR, EU, US and UK — with band and cup charts on screen. Cups to Grams Converter Convert cups, tablespoons and teaspoons to grams by ingredient — or the other way around — with densities from the King Arthur and FAO databases. Oven Temperature Converter Convert oven temperatures between Celsius, Fahrenheit and British gas marks, with fan-oven adjustment and the Brazilian recipe names. Lab Test Unit Converter Convert blood test results between conventional and SI units — the factor comes from the molar mass and never goes out of date. Power Plugs & Voltage by Country Check which plug type, voltage and frequency a country uses, and whether your devices need an adapter, a voltage converter or both. IBGE Municipality Code Lookup Search for the official IBGE code of Brazilian state capitals and major cities — the 7-digit identifier used in government forms and APIs. Straight-Line Distance Between Brazilian Cities Pick two Brazilian cities and see the straight-line (great-circle) distance between them in kilometres, computed with the Haversine formula. Molar Mass Calculator Type a chemical formula and get the molar mass in g/mol, with the contribution of each element — using IUPAC 2021 atomic weights. Global Currency Converter Convert between any two currencies with daily exchange rates from the European Central Bank — 40+ currencies, no sign-up. Compound Interest Calculator Calculate compound interest with monthly contributions — see how your money grows over time. Quadratic Equation Solver Solve ax² + bx + c = 0 — see the discriminant, the roots and whether they are real or complex. Pressure Converter Convert between Pascal, bar, atm, psi, mmHg, kPa, millibar and inHg — instantly. Matrix Calculator Compute the determinant, transpose or inverse of a matrix up to 10×10 — with step-by-step results. Function Plotter Type a mathematical function and see its graph plotted on an interactive canvas with axes and grid. Z-Score Calculator Calculate the z-score and corresponding percentile from a value, mean and standard deviation. Confidence Interval Calculator Compute the confidence interval for a population mean from the sample mean, standard deviation and sample size. Random Sample Generator Draw a random sample of numbers from a population — with or without replacement, sorted for easy use. Depreciation Calculator Calculate asset depreciation using straight-line, declining balance or sum-of-years digits — with a year-by-year table. Working Capital Calculator Calculate net working capital and liquidity ratios — current, quick and cash — from your balance sheet figures. Payback Period Calculator Calculate the simple and discounted payback period of an investment from its cash flows. NPV & IRR Calculator Calculate the Net Present Value (VPL) and Internal Rate of Return (TIR) from a series of cash flows. Energy Unit Converter Convert between joules, calories, kilowatt-hours, BTU, electronvolts and other energy units. Density Converter Convert between kg/m³, g/cm³, g/mL, lb/ft³ and other density units. Torque Converter Convert between newton-metres, kilogram-force metres, pound-feet and other torque units. Flow Rate Converter Convert between litres per minute, cubic metres per hour, US gallons per minute and other flow rate units. Inflation Correction Calculator Correct a value from one year to another using IPCA or IGP-M — the two main Brazilian price indices. Coordinate Converter Convert geographic coordinates between decimal degrees, degrees-minutes-seconds and degrees-decimal-minutes. UTM Coordinate Converter Convert between UTM (easting, northing, zone) and decimal degrees — both ways. Distance Between Coordinates Calculate the straight-line distance between two geographic points using the Haversine formula. My Coordinates See your current geographic coordinates using your device's GPS — latitude, longitude and accuracy. Plus Code (Open Location Code) Convert between latitude/longitude and Plus Codes — Google's open addressing system for places without street names. Digital Compass Turn your phone into a compass — see the magnetic heading in degrees and the cardinal direction in real time. Cardinal Points Reference The 16 compass points with their abbreviations, degrees and full names — type a bearing to find the closest direction. Average Speed Calculator Calculate speed, distance or time from any two of the three — type two and the third is computed. Free Fall Calculator Calculate how long an object takes to fall from a given height, or how far it falls in a given time — with final velocity. Kinetic & Potential Energy Calculator Calculate kinetic energy from mass and velocity, potential energy from mass and height, or both at once. Dilution Calculator (C₁V₁ = C₂V₂) Solve the dilution equation for any unknown — concentration or volume — in one step. pH Calculator Enter pH, pOH, [H⁺] or [OH⁻] and see the other three instantly — at 25 °C. HP / CV / kW Power Converter Convert between horsepower (HP), cavalo-vapor (CV), kilowatts (kW) and BTU/h. 35mm Equivalent Focal Length Convert any focal length to its 35mm equivalent using the crop factor of your sensor. Digital Bubble Level Use your phone's accelerometer as a digital level — see the angle and a bubble indicator.