Feet per Second to Millimeter per Second Converter - Convert ft/s to mm/s
Accurate feet per second (ft/s) to millimeter per second (mm/s) converter using the exact identity mm/s = (ft/s) × 1524/5 = (ft/s) × 304.8. Includes worked steps, expanded tables, rounding rules, a large FAQ, tips, and structured data.
Exact identity: mm/s = (ft/s) × 1524/5 (equal to 304.8 × ft/s). Reverse: ft/s = (mm/s) × 5/1524. See all MetricCalc's speed unit converters.
About Feet per Second to Millimeter per Second Conversion
Feet per second (ft/s) is encountered in testing, mechanical specifications, and some regional standards. For precision mechanics and lab automation, millimeter per second (mm/s) provides finer control and reporting. Converting ft/s to mm/s lets customary-unit targets map onto actuator settings, feed rates, and controller limits expressed in SI subunits.
The conversion is exact: mm/s = (ft/s) × 304.8. For robust pipelines compute in m/s, convert to mm/s for device interfaces, and round once at presentation so values remain stable across UIs, PDFs, and exports.
Feet per Second to Millimeter per Second Formula
Exact relationship
Use either expression:
mm/s = (ft/s) × 1524/5
// equivalent decimal
mm/s = (ft/s) × 304.8
// inverse
ft/s = (mm/s) × 5/1524Derivation (exact):
1 ft = 0.3048 m, hence 1 ft/s = 0.3048 m/s = 304.8 mm/s ⇒ multiply ft/s by 304.8 to get mm/sRelated Speed Converters
What is Feet per Second (ft/s)?
ft/s measures feet traveled each second. With the foot defined exactly as 0.3048 meters, ft/s connects to SI with a fixed constant and is easy to translate to m/s and mm/s. It appears in design reviews, sports science, and certain regional standards. Using a precise identity ensures auditability across tooling and documents.
Always label units explicitly (ft/s vs mm/s) in legends, axis titles, and export headers to prevent ambiguity in mixed-unit contexts.
What is Millimeter per Second (mm/s)?
mm/s counts millimeters each second and is well-suited to precision motion, robotics, micro-assembly, and lab instrumentation. Mapping between mm/s and m/s (and hence ft/s) is a simple scaling-exact and reproducible-making downstream conversions straightforward.
Use explicit unit labels and keep a small CI set of anchor conversions to catch regressions when UI or localization changes.
Step-by-Step: Converting ft/s to mm/s
- Read the speed in ft/s.
- Multiply by 1524/5 (or 304.8) to obtain mm/s.
- Apply one presentation-time rounding step aligned with device precision or policy.
- Label units explicitly across UI, PDFs, and export headers.
Example walkthrough:
Input: 10 ft/s
Compute: mm/s = 10 × 1524 / 5
Output: 3,048 mm/s (UI rounding only)Common Conversions
| Feet per Second (ft/s) | Millimeter per Second (mm/s) |
|---|---|
| 1 | 304.8 |
| 2.5 | 762 |
| 5 | 1,524 |
| 10 | 3,048 |
| 25 | 7,620 |
| 50 | 15,240 |
| 60 | 18,288 |
| 80 | 24,384 |
| 100 | 30,480 |
| 120 | 36,576 |
Quick Reference Table (Reverse)
| Millimeter per Second (mm/s) | Feet per Second (ft/s) |
|---|---|
| 1,000 | 3.280839895 |
| 2,500 | 8.202099737 |
| 5,000 | 16.40419947 |
| 10,000 | 32.80839895 |
| 20,000 | 65.6167979 |
| 30,000 | 98.42519685 |
| 40,000 | 131.2335958 |
| 50,000 | 164.0419947 |
| 75,000 | 246.0629921 |
| 100,000 | 328.0839895 |
Precision, Rounding & Significant Figures
Operational rounding
Preserve full internal precision and round once at presentation. For very small/large outputs, scientific notation ensures readability without compromising significant figures.
Consistent documentation
Publish constants and inverse identities alongside examples, use explicit unit-suffixed fields (speed_fts, speed_mms), and maintain a small CI anchor set for round-trip validation.
Where This Converter Is Used
- Translating customary-unit specs to SI-aligned controller set-points in mm/s.
- Mixed-audience engineering reports that need both familiar and technical units.
- Compliance exports requiring explicit constants, inverses, and a documented rounding policy.
- Education/training materials bridging imperial and SI measures of speed.
Frequently Asked Questions
What is the exact formula to convert feet per second to millimeter per second?
From the exact definition 1 ft = 0.3048 m, 1 ft/s = 0.3048 m/s = 304.8 mm/s. Therefore mm/s = (ft/s) × 304.8, which equals (ft/s) × 1524/5 exactly.
Is 304.8 an approximation or exact?
It is exact. The international foot is defined as exactly 0.3048 meters. That exactness flows through to ft/s ↔ mm/s conversions.
What is the reverse identity from mm/s to ft/s?
Invert the factor: ft/s = (mm/s) × 5/1524 (exact). Numerically, ft/s ≈ (mm/s) × 0.003280839895.
Which unit should I store internally for computation?
Store meters per second (m/s). It integrates cleanly with physics equations. Convert to ft/s or mm/s for presentation and round once at output.
How should I round for dashboards and exports?
Keep full precision internally and apply a single presentation-time rounding step. Align decimals to instrument resolution or policy and document that policy near your constants and examples.
Does locale formatting change the result?
No. Locale affects only appearance (grouping and decimal symbols). The underlying numbers and identities remain exact.
What anchor pairs are helpful for tests?
1 ft/s = 304.8 mm/s; 5 ft/s = 1,524 mm/s; 10 ft/s = 3,048 mm/s; 50 ft/s = 15,240 mm/s. Use these for round-trip CI checks.
Where is ft/s → mm/s used in practice?
Translating customary-unit specs to SI subunits for actuator set-points, feed rates, or controller limits expressed in mm/s.
Can I paste scientific notation (e.g., 1.2e1 ft/s)?
Yes. The input accepts scientific notation. Extreme outputs switch to scientific notation to preserve significant figures.
Any mental-math shortcut?
Multiply ft/s by 300 for a quick mm/s estimate, then add 1.6% (since the exact factor is 304.8).
How should I label export fields?
Use explicit unit-suffixed names (speed_fts, speed_mms). Include a short methodology note with constants, inverse identity, rounding policy, and anchor conversions.
Is ft/s an SI unit?
No. ft/s is non-SI, but it converts to SI exactly through 0.3048 meters per foot. That’s why the identities above are exact.
Tips for Working with ft/s & mm/s
- Use m/s as the compute base; expose ft/s/mm/s at the presentation edge.
- Round once at output and keep unit symbols explicit in all labels and exports.
- Maintain anchor conversions for regression testing when UI or localization changes.
- Document constants and inverse identities close to examples for quick audits.