All-in-One Unit Converter

Convert length, mass, temperature, area, volume, speed, time, and digital storage. Private by design—everything runs locally in your browser.

Choose Units & Convert

Tip: paste values like 10 km, 5ft, or 2 MiB — we’ll try to parse it.
Result

Shortcuts: Enter convert · S swap units · Ctrl/Cmd + K focus search.

About This Converter

This tool converts measurements across eight common categories—length, mass, temperature, area, volume, speed, time, and digital storage. It uses precise factors and well-tested formulas and runs entirely in your browser for privacy and speed.

How conversions work

  • Length — Base unit: metre (m). Metric (mm, cm, m, km) and imperial/US (in, ft, yd, mi) are supported. Conversions rely on exact definitions (e.g., 1 in = 2.54 cm, 1 mi = 1609.344 m). Examples: 3 m → ft, 10 km → mi.
  • Mass — Base unit: kilogram (kg). Includes mg, g, kg, tonne (t) and US customary units (oz, lb). Exact factors are used (e.g., 1 lb = 0.45359237 kg). Examples: 2.5 kg → lb, 8 oz → g.
  • Area — Base unit: square metre (m²). Metric (mm², cm², m², km²) and common land measures (ft², yd², ac, ha). Note that square conversions scale by the square of the length factor (e.g., 1 ft² = 0.09290304 m²). Examples: 120 m² → ft², 1 ac → m².
  • Volume — Base unit: cubic metre (m³). Metric (mL, L, m³), cubic units (in³, ft³), and US volume units (fl oz, cup, pint, quart, gallon). US customary factors are included; 1 gal (US) ≈ 3.785411784 L. Remember: volume scales with the cube of the length factor (e.g., 1 ft³ ≈ 28.316846592 L). Examples: 2 L → cup (US), 5 gal (US) → L.
  • Speed — Base unit: metres per second (m/s). Includes km/h, mph, and knots (kn). Examples: 100 km/h → mph, 12 m/s → kn.
  • Time — Base unit: second (s). Includes ms, s, min, h, day, week. Conversions are exact within the fixed units (no calendars involved). Examples: 90 min → h, 3 days → h.
  • Digital storage — Base unit: byte (B). Supports SI decimal (kB, MB, GB, TB = ×1000) and binary IEC (KiB, MiB, GiB, TiB = ×1024). Also supports bits (b) by converting via 8 bits = 1 byte. Examples: 100 MB → MiB, 8 Gb → GB.
  • Temperature — Uses formulas (not factors): °F ↔ °C via °F = °C × 9/5 + 32; K ↔ °C via K = °C + 273.15. Examples: 72 °F → °C, 300 K → °C.

Accuracy, formatting & parsing

  • Precision: Results use stable, standard factors and are formatted with up to 10 decimal places or scientific notation for very large/small values.
  • Smart input: Paste natural inputs like 10 km, 5ft, 2 MiB, or 72 F—the parser will detect units and adjust the “From” selector automatically.
  • Units vs. labels: Digital storage distinguishes decimal (MB) and binary (MiB). Area/volume reflect squared/cubed scaling.

Quick tips

  • Use the Swap button to reverse a conversion instantly.
  • Hit Convert or press Enter after typing a value; try pasting with units to save time.
  • Click Copy Result to share or document your calculation.
  • For temperature, choose the correct scale (°C, °F, K)—they’re formula-based, not factor-based.
  • For digital storage, pick decimal (MB/GB) when matching drive labels and binary (MiB/GiB) when matching OS/file-size tools.

5 Fun Facts about Unit Conversion

Feet aren’t exact thirds

One foot is defined as exactly 0.3048 m—so an inch is 2.54 cm, not a repeating fraction. “Rounding” inches to metric can stack error fast.

Exact defs

Binary vs decimal bytes

1 MB is 1,000,000 bytes; 1 MiB is 1,048,576 bytes. That 4.86% difference is why new drives look “smaller” in your OS.

Storage illusion

Temperatures break the factor rule

Most units convert with multipliers; °C ↔ °F needs a formula. Add 40 to both and you get the same number: -40 °C = -40 °F.

Offset magic

Areas & volumes explode

Double a length and you quadruple area, octuple volume. Forgetting squared/cubed scaling is the classic DIY paint/soil miscalc.

Power of 2 & 3

Knots measure Earth

A knot is exactly one nautical mile per hour, tied to Earth’s circumference (1 NM = one minute of latitude). Handy for global distances.

Geodesy roots

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