Square inch (in²)
The square inch (symbol: sq in or in²) is a unit of area in the Imperial and US customary systems, equal to the surface area of a square with one-inch sides. Following the 1959 International Yard and Pound Agreement, one inch is defined as exactly 25.4 millimetres, making one square inch equal to 6.4516 square centimetres (6.4516 × 10⁻⁴ m²). It is extensively used in engineering, materials testing, and measuring small surface areas or pressure limits.
Metric
- Square kilometre (km²)6.45×10⁻¹⁰
- Hectare (ha)6.45×10⁻⁸
- Are (a)6.45×10⁻⁶
- Square metre (m²)6.45×10⁻⁴
- Square decimetre (dm²)0.06
- Square centimetre (cm²)6.45
- Square millimetre (mm²)645.16
- Square micrometre (µm²)645,160,041.63
- Square nanometre (nm²)6.45×10¹⁴
British/American
- Township6.92×10⁻¹²
- Square mile2.49×10⁻¹⁰
- Homestead9.96×10⁻¹⁰
- Acre1.59×10⁻⁷
- Rood6.38×10⁻⁷
- Square rod2.55×10⁻⁵
- Square6.94×10⁻⁵
- Square yard (yr²)7.72×10⁻⁴
- Square foot (ft²)0.01
- Square inch (in²)1
Other
- Metric dunam6.45×10⁻⁷
- Cypriot dunam4.82×10⁻⁷
- Iraqi dunam2.58×10⁻⁷
- Football pitch9.04×10⁻⁸
Brazilian
- Alqueire paulista2.67×10⁻⁸
- Alqueire mineiro1.33×10⁻⁸
- Alqueire baiano6.66×10⁻⁹
- Alqueire do norte2.37×10⁻⁸