Engineering unit converter

Method, step by step

1. The value is first converted to the SI base unit of its quantity (metre, square metre, cubic metre, kilogram, newton, pascal) by multiplying by the factor of the source unit.
2. The result is divided by the factor of the target unit, rounded to 12 significant digits to remove floating-point noise, and shown with at most 10 significant digits.
3. Temperature has no fixed factor: the value goes to kelvin (K = °C + 273.15) and then to the target unit.

Worked example

Common site and technical-office conversions, computed by the same converter:

• 1 ft (Foot) = 0.3048 m (Metre)
• 1 in (Inch) = 2.54 cm (Centimetre)
• 1 m² (Square metre) = 10.76391042 ft² (Square foot)
• 1 yd³ (Cubic yard) = 0.764554858 m³ (Cubic metre)
• 1 m³ (Cubic metre) = 1,000 L (Litre)
• 1 tf (Tonne-force) = 9.80665 kN (Kilonewton)
• 25 MPa (Megapascal) = 254.9290532 kg/cm² (Kilogram-force per cm²)
• 1 kg/cm² (Kilogram-force per cm²) = 0.0980665 MPa (Megapascal)
• 1 MPa (Megapascal) = 145.0377377 psi (Pound-force per in²)
• 30 °C (Celsius) = 86 °F (Fahrenheit)

Supported units

• Length: mm, cm, m, km, in, ft, yd, mi
• Area: mm², cm², m², ha, km², in², ft², yd², ac
• Volume: cm³, L, m³, in³, ft³, yd³, gal (US), gal (UK)
• Mass: g, kg, t, lb, oz
• Force: N, kN, kgf, tf, lbf
• Stress & pressure: Pa, kPa, MPa, N/mm², kN/m², kg/cm², t/m², psi, bar
• Temperature: °C, °F, K

Assumptions and default ratios

• Factors are derived from exact definitions, never rounded decimals: the inch is 0.0254 m, the pound 0.45359237 kg and standard gravity 9.80665 m/s².
• Kilogram-force and tonne-force use standard gravity, so one tonne-force is exactly 9.80665 kN.
• The tonne is the metric tonne (1000 kg); the US and imperial gallons are separate units in the list.

Frequently asked questions