Convert Centistokes to Square Millimeters per Second

Formula

mm²/s = cSt × 1

Derivation from SI units:

• 1 cSt = 0.01 St = 10⁻⁶ m²/s = 1 mm²/s
• 1 mm²/s = 10⁻⁶ m²/s = 1 cSt
• 1 cSt = 0.000001 m²/s ÷ 0.000001 m²/s per mm²/s = 1 mm²/s

Both units are defined exactly, so the factor is exact. Centistokes definition: centistokes; Square Millimeter per Second definition: square millimeter per second.

Worked examples

1. An ISO VG 46 hydraulic oil, about 46 cSt at 40 °C, is 46 mm²/s.
   46 cSt × 1 = 46 mm²/s
2. Water at 20 °C, about 1 cSt, is 1 mm²/s.
   1 cSt × 1 = 1 mm²/s

Where it's used

Lubricant and fuel viscosities in centistokes are identical to mm²/s, the SI form used by ISO 3448 viscosity grades.

Centistokes to other kinematic viscosity units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "centistokes (cSt)".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 2 with SI prefix milli.

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.