Last updated October 6, 2026 · Report an error
Momentum is measured in kilogram-meters per second in the SI system, but physics problems and engineering references sometimes use imperial units instead, based on pounds or slugs. This calculator converts momentum values between the SI unit and common imperial and CGS alternatives.
Unlike the Momentum Calculator, which computes momentum from a mass and velocity you supply, this tool is a pure unit converter for an already-known momentum value.
How it works
Enter a value, choose the unit you're converting from and to, and the calculator applies the standard conversion factor between kilogram-meters per second, gram-centimeters per second, pound-feet per second, and slug-feet per second.
- Enter value.
- Enter from.
- Enter to.
- Click Calculate to see your results.
Examples
Converting an imperial physics result
A momentum of 10 pound-feet per second converts to about 1.38 kilogram-meters per second, the SI-standard way the result would typically be reported.
Comparing engineering unit systems
A momentum value expressed in slug-feet per second is converted to kilogram-meters per second to compare against an SI-based calculation.
Who should use it
- Converting a physics problem's momentum result between imperial and SI units.
- Comparing engineering calculations that use different momentum unit conventions.
Industry applications
- Physics and engineering education
- Mechanical and aerospace engineering
Advantages
- Covers SI, CGS, and two common imperial momentum unit conventions.
- Shows the exact conversion factor used, not just the final answer.
- No account, subscription or watermark.
Limitations
- Does not compute momentum from mass and velocity — for that, use the Momentum Calculator instead.
Common mistakes to avoid
- Confusing pound-mass-based and slug-based imperial momentum units, which use different mass definitions.
- Not accounting for the SI-to-imperial scale difference when sanity-checking a converted result.
Best practices
- Confirm whether an imperial-unit source is using pound-mass or slug as its mass basis before converting.
- Use kilogram-meters per second as your default reference unit when comparing across different sources.
Tips
- Use the Momentum Calculator first if you need to compute momentum from mass and velocity — this tool only converts an already-known value.
- Double-check whether an imperial source uses pound-mass or slug as its underlying mass unit.