Convert Cubic Inches per Second to Cubic Feet per Second

Cubic Inch per Second (in³/s) to Cubic Foot per Second (ft³/s) flow rate conversion — enter any value below to get an instant result, or use the table for common values.

Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.

Value

From

Result

1 in³/s = 0.00057870497 ft³/s

1 Cubic Inch per Second = 0.00057870497 Cubic Feet per Second

1 Cubic Foot per Second = 1727.9962 Cubic Inches per Second

1 in³/s in every supported unit

Conversion chart: Cubic Inch per Second to Cubic Feet per Second

Conversion table

Cubic Inch per Second (in³/s)	Cubic Foot per Second (ft³/s)
0.01 in³/s	5.78705E-06 ft³/s
0.1 in³/s	5.78705E-05 ft³/s
1 in³/s	0.00057870497 ft³/s
2 in³/s	0.0011574099 ft³/s
3 in³/s	0.0017361149 ft³/s
5 in³/s	0.0028935249 ft³/s
10 in³/s	0.0057870497 ft³/s
20 in³/s	0.011574099 ft³/s
50 in³/s	0.028935249 ft³/s
100 in³/s	0.057870497 ft³/s
1000 in³/s	0.57870497 ft³/s

Cubic Inch per Second (in³/s)

Definition: A fine-grained US customary flow rate unit measuring cubic inches passing a point every second, suited to small hydraulic and mechanical flows.

History: Derived from the US customary cubic inch, adopted in mechanical and hydraulic engineering where component-scale volumes are naturally measured in inches rather than feet.

Current use: Used to rate small hydraulic pump and cylinder displacement rates, and fuel injector flow specifications in the US.

Cubic Foot per Second (ft³/s)

Definition: A US customary flow rate unit measuring cubic feet passing a point every second — commonly abbreviated cfs — the standard unit for large-scale water flow in the US.

History: Derived from the US customary cubic foot once it was standardized, and adopted by American civil engineers as the natural unit for describing river and channel discharge.

Current use: The standard unit used by the US Geological Survey and civil engineers to report river discharge, dam spillway capacity, and stormwater channel design flow.

Supported Units

Unit	Symbol	In m³/s
Cubic Meter per Second	m³/s	1 m³/s
Cubic Meter per Minute	m³/min	0.016666667 m³/s
Cubic Meter per Hour	m³/h	0.0002777778 m³/s
Cubic Meter per Day	m³/d	1.15741E-05 m³/s
Liter per Second	L/s	0.001 m³/s
Liter per Minute	L/min	1.66667E-05 m³/s
Liter per Hour	L/h	2.77778E-07 m³/s
Liter per Day	L/d	1.15741E-08 m³/s
Milliliter per Second	mL/s	1E-06 m³/s
Gallon (US) per Second	gal(US)/s	0.0037854118 m³/s
Gallon (US) per Minute	gal(US)/min	6.30902E-05 m³/s
Gallon (US) per Hour	gal(US)/h	1.0515E-06 m³/s
Gallon (US) per Day	gal(US)/d	4.38126E-08 m³/s
Gallon (UK) per Minute	gal(UK)/min	7.57682E-05 m³/s
Gallon (UK) per Hour	gal(UK)/h	1.2628E-06 m³/s
Barrel (US) per Day	bbl(US)/d	1.84013E-06 m³/s
Barrel (US) per Hour	bbl(US)/h	4.41631E-05 m³/s
Cubic Foot per Second	ft³/s	0.028316847 m³/s
Cubic Foot per Minute	ft³/min	0.0004719474 m³/s
Cubic Foot per Hour	ft³/h	7.86579E-06 m³/s
Cubic Inch per Second	in³/s	1.63871E-05 m³/s
Cubic Yard per Second	yd³/s	0.76455486 m³/s

About These Parameters

Value: The flow rate value you want to convert, expressed in the "From" unit. Accepts decimals.
From Unit: The unit your input value is currently measured in — a pump datasheet's L/min, a duct fan's CFM, or a well's GPM.
To Unit: The unit you want the result converted into. Use the swap button to flip From and To instantly.

How Flow Conversion Works

The Formula

Every unit here is defined by a fixed multiplier relative to cubic meters per second. To convert a value from one unit to another:

result = value × (factor of "From" unit ÷ factor of "To" unit)

For Cubic Inch per Second → Cubic Foot per Second: multiply by 0.00057870497. For example, 1 in³/s × 0.00057870497 = 0.00057870497 ft³/s.

Volumetric Flow vs. Mass Flow

Every unit on this page measures volumetric flow — the VOLUME of fluid moving past a point per unit time, regardless of what that fluid weighs. That's the right measure for most liquids, since a liter of water always occupies the same space. For compressible gases, however, the same volume can represent very different masses depending on temperature and pressure, which is why processes like natural gas metering or compressed-air sizing often need MASS flow instead — the site's separate Flow - Mass Converter covers units like kilograms per second for exactly that case.

US vs. Imperial Gallons

A US gallon and a UK (imperial) gallon are not the same size — the imperial gallon is about 20% larger (roughly 4.546 liters versus the US gallon's 3.785 liters). That means "gallons per minute" means two different physical flow rates depending on which gallon is meant, and mixing them up is a common real-world error when comparing British and American pump, hose, or fixture specifications. Always check whether a gal/min figure is US or UK before treating it as equivalent — this converter keeps them as clearly separate units for exactly that reason.

Example

A flow rate of 1 in³/s equals 0.00057870497 ft³/s. For scale, a typical residential shower head flows around 2 US gallons per minute (roughly 7.6 L/min), a home HVAC return duct might move 400-800 CFM of air, and a moderate river might discharge several hundred cubic feet per second.

Frequently Asked Questions

How many Cubic Feet per Second are in 1 Cubic Inch per Second?

1 Cubic Inch per Second (in³/s) equals exactly 0.00057870497 Cubic Feet per Second (ft³/s).

What's the difference between GPM and CFM?

GPM (gallons per minute) measures liquid flow, most often water, while CFM (cubic feet per minute) measures gas or air flow, most often in HVAC ductwork and compressed-air systems. They're both volumetric flow units, just conventionally applied to different kinds of fluid and scaled to different everyday magnitudes.

How do I convert between US and UK gallons per minute?

Select "Gallon (US) per Minute" or "Gallon (UK) per Minute" as your From or To unit in the converter above — the two are kept as distinct units because the imperial gallon is about 20% larger than the US gallon, so the same physical flow rate produces a different number in each system.

How accurate are these conversions?

Every conversion factor used here is the exact, internationally recognized relationship between the underlying volume and time units — results are limited only by floating-point display precision, not by rounded conversion constants.

Why is oil production measured in barrels per day?

The 42-US-gallon petroleum barrel became the oil industry's standard unit in the early 20th century, and "barrels per day" (bbl/d) stuck as the universal way to report well production, refinery throughput, and pipeline capacity — even in countries that otherwise use metric units for everything else.

Convert Cubic Inch per Second to Other Flow Units

Possible Flow Conversions