Convert Square inches per second to Square millimetres per second
Convert Square inches per second (in²/s) to Square millimetres per second (mm²/s) instantly and accurately.
Conversion Formula
mm²/s = in²/s × 645.16
About Square inches per second
The square inch per second (in²/s) equals 0.0254² = 6.4516 × 10⁻⁴ m²/s. It is the coherent FPS kinematic unit based on the inch, found in US fluid power, hydraulics, and bearing-design references. 1 in²/s = 645.16 cSt = 6.4516 St.
About Square millimetres per second
The square millimetre per second (mm²/s) equals 10⁻⁶ m²/s, numerically identical to 1 centistoke (cSt). It is the preferred SI-consistent expression: ISO 3104, DIN 51562, and ASTM viscosity standards all use mm²/s interchangeably with cSt. Water at 20 °C ≈ 1.004 mm²/s; SAE 10W-30 at 100 °C: 9.3-12.5 mm²/s. 1 mm²/s = 1 cSt.
Quick Reference Table
| Square inches per second (in²/s) | Square millimetres per second (mm²/s) |
|---|---|
| 1 in²/s | 645.16 mm²/s |
| 2 in²/s | 1290.32 mm²/s |
| 5 in²/s | 3225.8 mm²/s |
| 10 in²/s | 6451.6 mm²/s |
| 25 in²/s | 16129 mm²/s |
| 50 in²/s | 32258 mm²/s |
| 100 in²/s | 64516 mm²/s |