Precision Physical Units & Metric-Imperial Conversion

Unit Converters

Switch effortlessly between metric, imperial, and scientific measurement standards. Every tool executes entirely in your browser with zero latency, verified thermodynamic constants, and complete mathematical proofs.

Bidirectional Multi-Scale Engine

Temperature Converter

Convert instantly between Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R). Features real-time dual inputs, visual mercury spectrum thermometer, physical benchmarks, and step-by-step algebraic formulas.

Physical benchmarks: Freezing, Body temp, Boiling & Baking

Thermodynamic absolute zero boundary checking

Launch Temperature Converter

Metric & Imperial Scaling

Length & Distance Converter

Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. Features compound feet and inches height mode (e.g. 5' 10"), multi-unit matrix, and physical scale benchmarks.

Compound feet & inches height & carpentry mode

Exact 1959 international yard & pound SI coefficients

Launch Length Converter

Mass & Culinary Weights

Weight & Mass Converter

Convert between grams, kilograms, metric tonnes, ounces, pounds, and British stones. Designed for cooking recipes, shipping logistics, fitness weigh-ins, and scientific experiments.

Stone and pound dual-unit formatting (e.g. 11 st 4 lb)

International avoirdupois pound standard

Launch Weight Converter

Recipes & Baking

Cooking Measurement Converter

Convert cups to grams for 29 ingredients, milliliters to cups, tablespoons to grams, and gallons to liters. Switch between US, UK imperial, and metric cups.

Ingredient densities for flour, sugar, butter & more

US customary, UK imperial & metric cup definitions

Launch Cooking Converter

Real Estate & Land

Area & Land Converter

Convert square feet to square meters, acres to hectares, square yards, square miles, and km² for property listings, flooring, farmland, and surveys.

Parking space to Central Park area benchmarks

Exact international foot and acre definitions

Launch Area Converter

Pressure · Power · Torque

Engineering Unit Converter

Convert psi to bar and kPa, horsepower to kW and metric PS, and newton-meters to pound-feet. Built for mechanics, engineers, and car enthusiasts.

Tire, engine and torque-wrench benchmarks

Exact pound-force, SI pascal, watt and newton-meter

Launch Engineering Converter

Storage & Bandwidth

Data Storage & Speed Converter

Convert bytes, KB, MB, GB, TB, and binary GiB, plus internet speeds from Mbps to MB/s. See why a 1 TB drive shows 931 GB.

Decimal (SI) vs binary (IEC) prefixes side by side

IEC 80000-13 binary prefix definitions

Launch Data Converter

Epoch Time for Developers

Unix Timestamp Converter

Convert Unix epoch timestamps to human-readable dates and back in any timezone. Paste seconds, milliseconds, microseconds, nanoseconds or date strings — the unit is auto-detected.

Auto-detects seconds, ms, µs and ns

IANA timezone database with DST handling

Launch Unix Timestamp Converter

Conversion Charts

kg to lbs lbs to kg lbs to grams grams to ounces ounces to grams Nm to ft-lbs ft-lbs to Nm psi to bar bar to psi kW to hp hp to kW Mbps to MB/s MB to GB GB to MB hectares to acres acres to hectares acres to m² m² to ft² ft² to m²

Scientific Traceability & Physical Standards

Why Physical Units Require Dedicated Architecture

Unlike abstract arithmetic where numbers represent dimensionless ratios or percentages, unit conversions bridge physical reality and legal definitions. Temperature conversion relies on thermodynamic offsets (such as the +32°F ice point and absolute zero at -273.15°C), while distance and weight follow international treaty agreements defined by the International Bureau of Weights and Measures (BIPM).

Zero-Loss Fractional Computation

Web converters often suffer from floating-point accumulation errors when converting repeated steps. Open Calculators applies rational fractions (such as exact 9/5 and 5/9 multipliers) rather than truncated decimal approximations (like 1.8 and 0.5556) during internal intermediate calculations to guarantee exact outputs.