Math & Measurement Tools

Solve everyday math, unit, geometry, date, display, home, vehicle, and material questions with visible formulas and inputs you can check.

Updated August 12, 2026

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71 of 71 tools shown

Core Math

Everyday arithmetic, sequences, factors, powers, and display calculations.

22 tools

Any Base ConverterConvert signed whole numbers between bases 2 and 36 without losing precision, with the source base and letter casing kept visible.Binary Octal Decimal Hex ConverterEnter one signed whole number in binary, octal, decimal, or hexadecimal and see all four exact representations together.BCD ConverterConvert decimal digits to binary-coded decimal or decode BCD nibbles, with packed-byte and unpacked-digit layouts stated explicitly.Gray Code ConverterConvert a fixed-width binary value to reflected Gray code or recover binary while preserving every leading zero.Binary Arithmetic ToolAdd, subtract, or multiply signed binary integers exactly and check whether the result fits a selected two’s-complement width.Bitwise Logic ToolApply AND, OR, XOR, NOT, NAND, NOR, or XNOR to fixed-width binary words and inspect unsigned and signed interpretations.Binary Shift & Rotate ToolShift or rotate one fixed-width binary word with visible truncation, zero fill, or sign extension.Scientific Notation ConverterConvert ordinary decimal text to normalized scientific notation or expand scientific notation without floating-point rounding.Scientific CalculatorEvaluate a bounded arithmetic expression with parentheses, powers, roots, trigonometry, and logarithms.Pi Digits ExplorerInspect a bounded prefix of pi and copy only the visible digits you requested.Percentage CalculatorFind a percentage of a value, a percentage change, or what percent one value is of another.Prime Number GeneratorList prime numbers up to a safe integer limit using a visible sieve result.Arithmetic Sequence CalculatorCalculate a selected term and bounded list for a sequence with a constant difference.Geometric Sequence CalculatorCalculate a selected term and bounded list for a sequence with a constant ratio.24 Game SolverTry four whole numbers with basic arithmetic to find a valid expression equal to 24.Absolute Value CalculatorShow a number’s absolute value and signed distance from zero.GCD & LCM CalculatorFind the greatest common divisor and least common multiple of two whole numbers.Prime Factorization CalculatorBreak one safe positive whole number into a reviewable prime-product form.Powers & Roots CalculatorCalculate an exponent, a positive nth root, and common square and cube forms.Natural Logarithm CalculatorCalculate the natural logarithm and exponential for a positive real number.Screen PPI CalculatorCalculate display pixel density from resolution and diagonal size.Display Viewing Distance CalculatorEstimate a 30-degree field-of-view viewing distance from screen diagonal size.

Units & Measurement

Transparent unit conversions using named fixed factors and visible assumptions.

17 tools

Data Storage ConverterConvert common decimal and binary data-storage units with the chosen source and target visible.Mass & Weight ConverterConvert grams, kilograms, metric tonnes, ounces, pounds, and US short tons.Force ConverterConvert newtons, kilonewtons, pound-force, kilogram-force, and dyne values.Length ConverterConvert millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles.Power ConverterConvert watts, kilowatts, megawatts, horsepower, and BTU per hour.Nautical Speed ConverterConvert knots, nautical miles per hour, kilometers per hour, and miles per hour.Speed ConverterConvert meters per second, kilometers per hour, miles per hour, and feet per second.Speed of Sound CalculatorEstimate the speed of sound in dry air from temperature using a stated linear approximation.Angle ConverterConvert degrees, radians, gradians, arcminutes, and arcseconds.Volume ConverterConvert liters, milliliters, cubic meters, US gallons, US fluid ounces, cups, and cubic feet.Pressure ConverterConvert pascals, kilopascals, bar, atmosphere, psi, and millimeters of mercury.Density ConverterConvert kilograms per cubic meter, grams per cubic centimeter, pounds per cubic foot, and pounds per cubic inch.Area ConverterConvert square meters, square kilometers, hectares, acres, square feet, square yards, and square miles.Energy ConverterConvert joules, kilojoules, watt-hours, kilowatt-hours, calories, kilocalories, and BTU.Temperature ConverterConvert Celsius, Fahrenheit, Kelvin, and Rankine temperatures with formula-based results.Time Unit ConverterConvert seconds, minutes, hours, days, weeks, and a conventional 365.2425-day year.Latitude/Longitude DMS ConverterConvert signed decimal coordinates to degrees, minutes, seconds, and cardinal directions.

Geometry & Solids

Shape formulas with dimensions you can inspect before using an estimate.

10 tools

Circle CalculatorCalculate radius, diameter, circumference, and area from one known circle measurement.Sector & Annulus CalculatorCalculate a circular sector area and arc length or the area between two concentric circles.Trapezoid Area CalculatorCalculate trapezoid area from the two parallel bases and perpendicular height.Parallelogram Area CalculatorCalculate parallelogram area from base and perpendicular height.Equilateral Triangle CalculatorCalculate equilateral-triangle height, area, perimeter, inradius, and circumradius from side length.Ellipse & Hexagon Area CalculatorCalculate ellipse area or regular-hexagon area and perimeter from its visible dimensions.Rectangular Prism CalculatorCalculate rectangular-prism volume, total surface area, and space diagonal.Cylinder CalculatorCalculate a right circular cylinder’s volume, lateral area, total area, and circumference.Cone CalculatorCalculate a right cone’s volume, slant height, lateral area, and total surface area.Sphere & Hemisphere CalculatorCalculate sphere and hemisphere volume, curved area, and total surface area from radius.

Date & Time

Calendar and clock calculations that keep the selected dates and conventions visible.

8 tools

Shelf Life Date CalculatorAdd a supplied shelf-life interval to a manufacture date without making food-safety or product-quality claims.12/24 Hour Time ConverterConvert a selected 24-hour local clock value into a clear 12-hour AM/PM representation.Age CalculatorCalculate completed calendar years, months, and days between a birth date and a reference date.Date Add & Subtract CalculatorAdd or subtract a whole number of calendar days from a selected reference date.Time Difference CalculatorCalculate elapsed time between two local clock readings, including an optional overnight end time.Day of Year & Week CalculatorShow the weekday, calendar day of year, ISO week number, and leap-year status for a date.UNIX Timestamp ConverterConvert UNIX seconds or milliseconds into UTC and local date-time values, or turn a timezone-aware date into timestamps.Duration FormatterConvert non-negative seconds into days and HH:MM:SS or parse a bounded D HH:MM:SS duration back into seconds.

Everyday Estimates

Cost, travel, device, and household estimates that clearly separate inputs from outcomes.

5 tools

EV Charging Cost CalculatorEstimate charging energy and cost from battery capacity, state of charge, efficiency, and local price.Fuel Economy CalculatorCalculate distance-per-fuel and fuel-per-distance values without assuming a currency or fuel price.Planetary Weight CalculatorEstimate how the same mass would weigh under standard surface gravity values on major solar-system bodies.Pet Age CalculatorShow a common age-equivalence estimate for a dog or cat, with no veterinary or health interpretation.Smoking Cost CalculatorCalculate supplied spending over day, month, and year without health, cessation, or financial advice claims.

Materials & Properties

Formula-only material calculations, not safety, quality, or certification decisions.

5 tools

Water Hardness ConverterConvert calcium-carbonate equivalent hardness units without judging water quality or safety.Wood Density CalculatorCalculate density from mass and rectangular volume using the units you selected.Brinell Hardness CalculatorCalculate a Brinell hardness number from the supplied load, ball diameter, and indentation diameter.Paper Weight & Thickness CalculatorEstimate sheet mass from basis weight and dimensions, or material density from measured thickness.Stainless Steel Weight CalculatorEstimate the mass of a rectangular plate, round tube, or square tube from dimensions and selected density.

Home Projects

Coverage and quantity planning tools with waste factors and real-world checks disclosed.

4 tools

Wallpaper CalculatorEstimate wallpaper rolls from wall dimensions, roll coverage, openings, and a chosen waste allowance.Curtain Fabric CalculatorEstimate curtain fabric length from track width, finished drop, fullness, fabric width, and hems.Flooring & Tile CalculatorEstimate flooring or tile quantity from room dimensions, product coverage, and waste allowance.Paint Coverage CalculatorEstimate paint volume from surface area, openings, coats, labeled coverage, and waste allowance.

METHOD BEFORE RESULT

Math tools that keep the question and limits visible

Choose a calculator by the question in front of you: convert an exact integer or bit pattern, solve an arithmetic expression, extend a sequence, convert units, measure a shape, compare dates and durations, estimate display density, plan a home project, or check a formula-based material quantity. The 71 tools group related jobs together so you can move from a quick answer to the next useful calculation without learning a new interface each time.

Every calculation runs in the current browser tab. Values are not uploaded, saved to an account, or used to make a recommendation. The visible result always depends on the fields and option labels shown above it. This approach is useful for private scratch work: change one input, run the formula again, and compare the outcome without relying on a remote black box.

Units need named conventions

Conversion is only reliable when the source and target unit are explicit. SI factors, customary units, data-storage prefixes, and temperature scales are not all interchangeable. These pages label decimal and binary storage separately, use a formula for temperature, and avoid pretending that a unit relationship supplies real-time facts such as an energy tariff, a commodity price, or a product specification.

Keep dimensions consistent before moving into an area, volume, density, or material calculation. A result can be arithmetically correct yet useless if centimeters, meters, kilograms, and pounds are mixed without conversion. The calculators show the unit selected by the visitor, but the measurement itself remains the visitor’s responsibility.

Estimates are not certifications

Home, materials, vehicle, and display tools make a limited claim: they calculate the consequence of the supplied inputs and stated formula. A wallpaper roll count cannot inspect pattern repeat; a paint estimate cannot assess a surface; a steel-weight estimate cannot confirm alloy grade; and a Brinell formula cannot certify a test. Those boundaries are written on the relevant pages so a convenient result is not mistaken for an approval or professional instruction.

For a practical purchase or project, use the result as a starting quantity and then check manufacturer coverage, tolerances, product instructions, supplier data, and local requirements. When a detail is unknown, it is safer to state the uncertainty than to have a calculator quietly invent it.

Private arithmetic, checkable output

Most pages accept values within deliberate limits and stop with an error when a value is missing, malformed, incompatible, or too large for a sensible in-browser calculation. Base and bitwise tools use exact whole-number arithmetic and expose width or overflow rules. The Scientific Calculator accepts a restricted math vocabulary and rejects code, variables, imports, assignment, and arbitrary names; its ordinary real-number calculations use IEEE 754 floating-point arithmetic, so rounding remains visible.

Use each tool for the question it documents, then follow a related link only when the next task truly changes. This keeps the directory quick to scan and prevents you from carrying the wrong inputs, assumptions, or limits into another result.

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