Convert Miles per Hour to Feet per Second - Speed Converter
This converter converts a single numeric speed value from miles per hour (mph) into feet per second (ft/s) using the fixed mathematical relationship between the units. It is suitable for engineers, safety professionals, athletes, educators, and anyone who needs a quick, reliable unit conversion.
The conversion is exact in mathematical terms because both units are defined from fixed length and time units. Practical results should account for measurement uncertainty, instrument calibration, and appropriate rounding for your application.
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Methodology
The conversion uses the exact relationship between the base units: 1 mile = 5280 feet and 1 hour = 3600 seconds. No empirical calibration is required for the arithmetic conversion itself.
Recommended practice for technical or regulatory reporting is to follow relevant measurement standards and document rounding and uncertainty. Refer to national and international guidance for best practices on units and measurement reporting.
Worked examples
60 mph → 60 × 1.4666666666667 = 88 ft/s.
1 mph → 1 × 1.4666666666667 = 1.4666666666667 ft/s (commonly reported as 1.46667 ft/s).
0.5 mph → 0.5 × 1.4666666666667 = 0.73333333333335 ft/s (report as 0.73333 ft/s if using five significant figures).
Key takeaways
Conversion is a direct multiplication by the exact factor 5280/3600 = 1.4666666666667.
When reporting converted values, state the number of significant figures and consider instrument uncertainty and calibration requirements where applicable.
Further resources
Expert Q&A
Is the conversion exact?
The mathematical relationship is exact because both mile and second are defined lengths and times. The numeric factor 5280/3600 reduces to 1.466666... which is a repeating decimal. When reporting results, round to an appropriate number of significant figures for your use case.
How many decimal places should I use?
Choose decimals based on measurement precision and context. For general use, four to six significant figures are common. For legal, safety, or instrument calibration reports, follow the precision requirements specified by the governing standard or instrument documentation.
Do I need to calibrate anything to use this converter?
No calibration is needed for the arithmetic conversion. However, if you are converting measured speeds from instruments, ensure those instruments are calibrated and their uncertainties documented according to applicable standards.
Which standards should I consult for measurement and reporting?
Consult recognized standards and guidance such as national metrology guidance and international standards for quantities and units. Examples include guidance published by national metrology institutes and international standards organizations for consistent unit use and measurement reporting.
Can I convert back from ft/s to mph?
Yes. The inverse factor is 1 / 1.4666666666667 = 0.68181818181818, so mph = ft/s × 0.68181818181818.
Sources & citations
- NIST - SI Units and Definitions — https://www.nist.gov/pml/weights-and-measures/si-units
- ISO - Quantities and Units (ISO standards overview) — https://www.iso.org/standards.html
- IEEE Standards Overview — https://www.ieee.org/standards/index.html
- OSHA - Occupational Safety and Health Administration — https://www.osha.gov