Understanding Volume Flow Rate
Volume flow rate tells us how much space a fluid occupies over time. In the engineering world it appears as cubic feet per hour (ft³/h) or cubic centimeters per second (cm³/s). Both belong to the same measure—volume flow rate—so they can be swapped with a single, reliable factor.
What is a Cubic Foot per Hour (ft³/h)?
A cubic foot is a cube 1 ft on each side. When we say “per hour,” we are measuring how many of those cubes pass a point in one hour. It is common in HVAC, water‑treatment, and fuel‑delivery calculations in the United States.
What is a Cubic Centimeter per Second (cm³/s)?
A cubic centimeter is a cube 1 cm on each side. “Per second” gives a much finer time resolution, which is useful in laboratory work, medical devices, and any system where rapid flow changes matter.
Exact Conversion Factor
The relationship is fixed by the definitions of the foot and the centimeter:
- 1 ft = 30.48 cm
- 1 ft³ = (30.48)³ cm³ = 28,316.846592 cm³
- 1 hour = 3,600 seconds
Therefore:
1 ft³/h = 7.865235720 cm³/s
For everyday use we round to four decimal places: 1 ft³/h ≈ 7.8652 cm³/s.
Conversion Formula
To move from cubic feet per hour to cubic centimeters per second, multiply by the factor:
cm³/s = ft³/h × 7.865235720
Worked Example
Imagine a small pump delivers 25 ft³/h. How many cubic centimeters per second is that?
- Apply the formula: 25 ft³/h × 7.865235720
- Calculate: 25 × 7.865235720 = 196.630893 cm³/s
- Round to four decimal places: **196.6309 cm³/s**
The pump moves roughly 197 cm³ every second—a handy number when sizing downstream piping or sensors.
Cubic Foot per Hour to Cubic Centimeter per Second Conversion Table
Each row applies the same rule: multiply the value in ft³/h by 7.865235720 and round to four decimal places.
| Cubic Foot per Hour (ft³/h) | Cubic Centimeter per Second (cm³/s) |
|---|---|
| 1 ft³/h | 7.8652 cm³/s |
| 2 ft³/h | 15.7305 cm³/s |
| 5 ft³/h | 39.3262 cm³/s |
| 10 ft³/h | 78.6524 cm³/s |
| 20 ft³/h | 157.3047 cm³/s |
| 50 ft³/h | 393.2618 cm³/s |
| 100 ft³/h | 786.5236 cm³/s |
| 500 ft³/h | 3,932.6179 cm³/s |
Practical Applications
- HVAC design: Convert airflow rates to metric units for international projects.
- Water treatment: Match pump specifications with sensor outputs that report in cm³/s.
- Fuel logistics: Translate delivery schedules from U.S. gallons per hour (via ft³/h) to metric flow meters.
- Laboratory equipment: Calibrate peristaltic pumps that are rated in ft³/h but need cm³/s for precise dosing.
Key Takeaway
One cubic foot per hour equals about 7.8652 cm³/s. Multiply any ft³/h value by this factor to get an accurate metric flow rate. Whether you’re sizing a pipe, programming a controller, or comparing international specs, the conversion is straightforward and reliable.
Ready to apply the conversion to your own project? Grab a calculator, plug in the numbers, and watch the units line up perfectly.