Convert Kilometers to Feet – Length Converter
This converter transforms a length given in kilometers (km) to feet (ft) using the standard international relationship between the metre and the foot. It is intended for everyday conversions, engineering estimates, and documentation where the international foot (1 ft = 0.3048 m exactly) is appropriate.
For high-precision surveying or legacy data that use the US survey foot, see the methodology and FAQs for guidance on differences. The tool reports mathematical conversion; measurement uncertainty from instruments or geodetic calculations is not included.
Interactive Converter
Convert between kilometer and foot with precision rounding.
Quick reference table
| Kilometer | Foot |
|---|---|
| 1 km | 3,280.8399 ft |
| 5 km | 16,404.1995 ft |
| 10 km | 32,808.399 ft |
| 25 km | 82,020.9974 ft |
| 50 km | 164,041.9948 ft |
| 100 km | 328,083.9895 ft |
Methodology
The conversion uses the International System of Units (SI) definition of the metre and the internationally agreed definition of the foot as exactly 0.3048 metres. Therefore 1 kilometre (1000 metres) equals 1000 / 0.3048 feet.
Where required for regulatory or technical work, users should verify which 'foot' definition is mandated (international foot vs US survey foot). For numerical display this tool follows standard IEEE floating-point rules for rounding when formatting output.
Worked examples
1 km = 3,280.8398950131 ft (using international foot).
0.5 km = 1,640.4199475066 ft.
5 km = 16,404.1994775656 ft.
Further resources
Expert Q&A
What exact conversion factor does this tool use?
This tool uses the international foot defined as exactly 0.3048 metres. That yields 1 kilometre = 1000 / 0.3048 = 3,280.839895013123... feet (displayed rounded).
Is there more than one definition of a foot?
Yes. The international foot (1 ft = 0.3048 m) is standard for most applications. The US survey foot is a slightly different exact value used historically in surveying. Use the US survey foot only when required by geodetic or legacy surveying specifications.
How many significant digits should I trust in the result?
Mathematically the conversion factor is exact given the definitions used. Practical trust in digits depends on input measurement accuracy and instrument uncertainty. For engineering documents, match digits to measurement uncertainty; for simple arithmetic, 4–6 significant digits are usually sufficient.
Does this conversion account for geographic or geodesic distance?
No. This is a unit conversion of scalar lengths. Converting coordinates or measuring great-circle/geodetic distances requires geodesy methods and ellipsoid models (not covered by this unit converter).
Why might displayed results differ slightly between tools?
Differences arise from (1) which foot definition is used, (2) rounding or decimal formatting, and (3) floating-point representation and rounding behavior per IEEE 754. This tool uses the international foot and rounds display output for readability.
Sources & citations
- NIST Special Publication 811, Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
- ISO - Quantities and units (ISO 80000 series overview) — https://www.iso.org/standard/30669.html
- IEEE Standard for Floating-Point Arithmetic (IEEE 754) — https://standards.ieee.org/standard/754-2019.html
- NIST note on the international foot and US survey foot — https://www.nist.gov/pml/us-survey-foot