Poise (P) and centipoise (cP) are units of dynamic viscosity, which measures how much a fluid resists flowing.
Relationship
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1 poise (P) = 100 centipoise (cP)
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1 centipoise (cP) = 0.01 poise (P)
SI Units
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1 poise = 0.1 pascal-second (Pa·s)
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1 centipoise = 0.001 pascal-second (Pa·s) = 1 millipascal-second (mPa·s)
Common Examples
| Fluid | Approximate Viscosity |
|---|
| Air (20°C) | 0.018 cP |
| Water (20°C) | 1 cP |
| Milk | 2–3 cP |
| Blood | 3–4 cP |
| Olive oil | 80–100 cP |
| Motor oil | 100–250 cP |
| Honey | 2,000–10,000 cP |
Quick Conversions
| Poise | Centipoise |
|---|
| 0.01 P | 1 cP |
| 0.1 P | 10 cP |
| 1 P | 100 cP |
| 5 P | 500 cP |
| 10 P | 1,000 cP |
Why Centipoise Is Common
Centipoise is widely used because many everyday liquids have viscosities close to 1 cP:
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Water at 20°C ≈ 1 cP
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Water becomes less viscous as it warms (e.g., about 0.65 cP at 40°C).
In laboratories and industry, viscosity is often reported in centipoise (cP) or millipascal-seconds (mPa·s), since:
1 cP = 1 mPa·s
These two units are numerically identical.