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Convert Stokes to Square inches per second

Instantly convert Stokes (St) to Square inches per second (in²/s) with our free online calculator.

Reviewed by Christopher FloiedUpdated

Formula: St to in²/smultiply by 0.155

Reference Table

Stokes (St)Square inches per second (in²/s)
10.155
50.775002
101.55
253.87501
507.75002
10015.5

How to Convert Stokes to Square inches per second

Formula

To convert Stokes (St) to Square inches per second (in²/s): multiply by 0.155

Step-by-Step

  1. Start with your value in Stokes (St).
  2. Multiply by 0.155 to perform the conversion.
  3. The result is your value expressed in Square inches per second (in²/s).

Conversion Factor

1 St = 0.155 in²/s

Reverse Factor

1 in²/s = 6.4516 St

Worked Example

Convert 25 Stokes to Square inches per second: 25 St = 3.87501 in²/s

About Stoke (St)

The CGS unit of kinematic viscosity equal to exactly 1 cm²/s (= 100 cSt = 10⁻⁴ m²/s). Named after Irish mathematician Sir George Gabriel Stokes, whose 1851 paper 'On the Effect of the Internal Friction of Fluids on the Motion of Pendulums' (Cambridge Phil. Trans.) established the laminar-drag formula F = 6πμrv (Stokes' law) — still the basis for terminal-velocity calculations for sedimenting particles, atmospheric aerosol settling rates, and laboratory particle-sizing techniques (Stokes diameter). The stoke as a unit is occasionally used directly for highly viscous fluids in geophysics and glass science where typical values are large enough that cSt would have many leading zeros: basaltic lava 10² to 10⁴ St at eruption temperature, granitic / rhyolitic lava 10⁹ to 10¹¹ St, the asthenosphere of Earth's mantle 10¹⁸ to 10²⁰ St, the lower mantle 10²² St, glass at the working point ~10⁴ St.

About Square inch per second (in²/s)

An imperial kinematic-viscosity unit equal to ≈ 6.4516 × 10⁻⁴ m²/s = 645.16 cSt (= 1/144 of ft²/s, since 1 ft² = 144 in²) per NIST SP 811. in²/s is a specialty unit used in some US mechanical-engineering contexts where ft²/s would be inconveniently large and cSt is the industry standard. Common in: older US hydraulic-fluid specifications (MIL-PRF-83282 fire-resistant hydraulic fluid, MIL-PRF-87257 low-temperature hydraulic fluid, and other US military-spec hydraulic fluid TSDs sometimes dual-list viscosity in cSt and in²/s); US aerospace bearing lubricant specifications (Pratt & Whitney and GE Aviation engine-oil specs); and pre-1990s US-edition machine-design textbooks where bearing-design problems were worked entirely in in / lbf / s. Most modern US engineering has converged on cSt and mPa·s. Convert in²/s to cSt by multiplying by 645.16; to m²/s by multiplying by 6.452 × 10⁻⁴.

Quick Facts

  • 1 Stoke equals 0.155 Square inches per second
  • 1 Square inch per second equals 6.4516 Stokes
  • Stoke is a unit of kinematic viscosity
  • Square inch per second is a unit of kinematic viscosity
  • This conversion is commonly used in fluid flow analysis, lubrication engineering, and process design
  • The Stoke belongs to the metric system
  • The Square inch per second belongs to the imperial system

Common Stoke to Square inch per second Conversions

Stokes (St)Square inches per second (in²/s)
0.010.00155
0.10.0155
0.250.0387501
0.50.0775002
10.155
20.310001
30.465001
50.775002
101.55
152.325
203.10001
253.87501
507.75002
7511.625
10015.5
25038.7501
50077.5002
1000155
5000775.002
100001550

Understanding Stokes

The Stoke (symbol: St) is a unit of kinematic viscosity. The CGS unit of kinematic viscosity equal to exactly 1 cm²/s (= 100 cSt = 10⁻⁴ m²/s). Named after Irish mathematician Sir George Gabriel Stokes, whose 1851 paper 'On the Effect of the Internal Friction of Fluids on the Motion of Pendulums' (Cambridge Phil. Trans.) established the laminar-drag formula F = 6πμrv (Stokes' law) — still the basis for terminal-velocity calculations for sedimenting particles, atmospheric aerosol settling rates, and laboratory particle-sizing techniques (Stokes diameter). The stoke as a unit is occasionally used directly for highly viscous fluids in geophysics and glass science where typical values are large enough that cSt would have many leading zeros: basaltic lava 10² to 10⁴ St at eruption temperature, granitic / rhyolitic lava 10⁹ to 10¹¹ St, the asthenosphere of Earth's mantle 10¹⁸ to 10²⁰ St, the lower mantle 10²² St, glass at the working point ~10⁴ St.

It belongs to the metric measurement system.

Stokes are commonly used in fluid flow analysis, lubrication engineering, and process design.

Understanding Square inches per second

The Square inch per second (symbol: in²/s) is a unit of kinematic viscosity. An imperial kinematic-viscosity unit equal to ≈ 6.4516 × 10⁻⁴ m²/s = 645.16 cSt (= 1/144 of ft²/s, since 1 ft² = 144 in²) per NIST SP 811. in²/s is a specialty unit used in some US mechanical-engineering contexts where ft²/s would be inconveniently large and cSt is the industry standard. Common in: older US hydraulic-fluid specifications (MIL-PRF-83282 fire-resistant hydraulic fluid, MIL-PRF-87257 low-temperature hydraulic fluid, and other US military-spec hydraulic fluid TSDs sometimes dual-list viscosity in cSt and in²/s); US aerospace bearing lubricant specifications (Pratt & Whitney and GE Aviation engine-oil specs); and pre-1990s US-edition machine-design textbooks where bearing-design problems were worked entirely in in / lbf / s. Most modern US engineering has converged on cSt and mPa·s. Convert in²/s to cSt by multiplying by 645.16; to m²/s by multiplying by 6.452 × 10⁻⁴.

It belongs to the imperial measurement system.

Square inches per second are commonly used in fluid flow analysis, lubrication engineering, and process design.

Why Convert Stokes to Square inches per second?

Converting between Stokes and Square inches per second is a frequent requirement for engineers, scientists, and students working with kinematic viscosity values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate kinematic viscosity conversion is essential.

Frequently Asked Questions

How do I convert Stokes to Square inches per second?

The CGS unit of kinematic viscosity equal to exactly 1 cm²/s (= 100 cSt = 10⁻⁴ m²/s). To convert Stokes to Square inches per second, multiply by 0.155. For example, 25 St equals 3.87501 in²/s.

How many Square inches per second are in 1 Stoke?

There are 0.155 Square inches per second in 1 Stoke.

How many Stokes are in 1 Square inch per second?

There are 6.4516 Stokes in 1 Square inch per second.

What is the formula for Stoke to Square inch per second conversion?

The formula is: multiply by 0.155. This means 1 St = 0.155 in²/s.

Is a Stoke bigger than a Square inch per second?

Yes. One Stoke is larger than one Square inch per second because 1 St equals 0.155 in²/s, which is less than 1.

When do you need to convert between Stokes and Square inches per second?

An imperial kinematic-viscosity unit equal to ≈ 6. Stoke and Square inch per second are both kinematic viscosity units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.

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