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Centipoise to Poise

1 Centipoise (cP) = 0.01Poise (P)

By KAMP Inc. / UnitOwl · Last reviewed:

Result
0.01 P
1 cP = 0.01 P
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How Many Poise in a Centipoise?

One centipoise (cP) equals exactly 0.01 poise (P). To convert centipoise to poise, divide the cP value by 100. The "centi" prefix literally means one-hundredth, just as a centimeter is one-hundredth of a meter. The poise is the CGS unit of dynamic viscosity, defined as 1 gram per centimeter per second (g/(cm·s)). While the centipoise is the everyday workhorse unit, the poise occasionally appears in older scientific literature, some reference tables, and certain academic contexts. Water at 20°C has a viscosity of 0.01 poise (1 cP), motor oil is about 1-5 poise (100-500 cP), and glycerin is about 15 poise (1,500 cP). The poise-to-cP relationship is straightforward but important for reading older viscosity data correctly. It is most useful when you compare legacy handbook values with modern instrument readouts. It also prevents factor-of-100 copy errors when archived data is brought into a modern worksheet or report. That context matters in audits, reformulation work, and historical method comparisons. It matters in technical due diligence too. It keeps old data usable reliably.

How to Convert Centipoise to Poise

  1. Start with your viscosity value in centipoise (cP).
  2. Divide by 100 to get poise (P).
  3. For example, 500 cP / 100 = 5 P.
  4. This is a simple metric prefix conversion: centi = 1/100.
  5. For the reverse, multiply poise by 100 to get centipoise.

Real-World Examples

A viscometer reads 150 cP. Express in poise.
150 / 100 = 1.5 P.
An older reference lists castor oil viscosity as 6.5 P. What is that in cP?
6.5 x 100 = 650 cP. Castor oil is quite viscous — about 650 times more viscous than water.
A polymer solution has a viscosity of 25,000 cP. Convert to poise.
25,000 / 100 = 250 P.
Pancake syrup is about 25 P. What is that in cP?
25 x 100 = 2,500 cP.

Quick Reference

Centipoise (cP)Poise (P)
10.01
20.02
50.05
100.1
250.25
500.5
1001
5005
1,00010

History of Centipoise and Poise

The poise was named after Jean Léonard Marie Poiseuille and was established as part of the CGS system of units. In the CGS framework, the poise (1 g/(cm·s)) was the natural viscosity unit. However, for most common fluids, the poise produced inconveniently small numbers (water is just 0.01 P), so the centipoise quickly became the practical standard. The centipoise had the fortunate property of making water's viscosity approximately unity (1 cP at 20°C), which simplified calculations and comparisons. When SI replaced CGS, the poise was superseded by the pascal-second (1 Pa·s = 10 P), and the centipoise by the millipascal-second (1 mPa·s = 1 cP). The poise itself is now rarely used, serving mainly as a historical bridge between older literature and modern practice.

Common Mistakes to Avoid

  • Dividing by 1,000 instead of 100. Dividing cP by 1,000 gives Pa·s, not poise. The factor between cP and P is 100 (centi = 1/100). The factor between cP and Pa·s is 1,000.
  • Confusing poise (P) with pascal-second (Pa·s). 1 P = 0.1 Pa·s, not 1 Pa·s. This factor-of-ten difference is easy to overlook.
  • Using poise in modern engineering calculations that expect SI units. If your equation uses kg, m, and s, you need Pa·s (not poise). Inserting poise values directly introduces a factor-of-10 error.
  • Assuming old viscosity tables labeled in poise refer to kinematic viscosity. Poise is a dynamic viscosity unit; stokes and centistokes are the kinematic units. Those are different properties, not just different labels.
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Frequently Asked Questions

Is the poise still used anywhere?
Rarely. It appears in some older scientific papers, certain textbook editions, and occasional reference tables. The centipoise has almost completely replaced it for practical use, and the Pa·s (or mPa·s) has replaced it for formal SI applications. You might encounter poise in literature from the mid-20th century or earlier.
What is the relationship between poise, centipoise, and Pa·s?
1 P = 100 cP = 0.1 Pa·s. Or equivalently: 1 Pa·s = 10 P = 1,000 cP. And 1 cP = 0.01 P = 0.001 Pa·s = 1 mPa·s. These relationships form a consistent chain connecting CGS and SI viscosity units.
Why was the poise replaced by the centipoise in practice?
Convenience. Water at 20°C is 0.01 P but 1.0 cP. Working with a unit where the most common reference fluid has a value of 1.0 is far more practical than one where it is 0.01. The same logic applies to why we use centimeters for everyday lengths rather than meters for small objects.
What does 1 poise feel like in practical terms?
1 poise equals 100 cP, which is roughly the viscosity of a light motor oil or a moderately thick syrup at room temperature. It is much thicker than water but still clearly pourable.
Why is water 0.01 poise instead of 1 poise?
Because the poise is a relatively large CGS unit for ordinary liquids. Water sits at 1 cP, and since 100 cP = 1 P, water becomes 0.01 P. That is exactly why centipoise became the practical daily-use unit.
Quick Tip

The poise, centipoise, and pascal-second chain is easy to remember: cP divided by 100 gives poise, and poise divided by 10 gives Pa·s. Or from the other end: Pa·s x 10 = poise, poise x 100 = cP, and Pa·s x 1,000 = cP. Keep water at 1 cP = 0.01 P = 0.001 Pa·s as your anchor.

Sources & References