# Feet to Kilometers (ft to km)

> Convert feet to kilometers: 1 ft = 0.0003048 km. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `feet-to-km` · Quantity: Length (`length`, base unit m) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/feet-to-km · This document: https://tttkmbb.com/conversion/feet-to-km.md · JSON: https://tttkmbb.com/conversion/feet-to-km.json (add `?value=` for a result)

## Formula

- `1 ft = 0.0003048 km`
- `kilometers = feet × 0.0003048`
- Reverse: `feet = kilometers × 3280.839895`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 ft = 0.001524 km
- 12.5 ft = 0.00381 km
- 100 ft = 0.03048 km

## Conversion table

| Feet (ft) | Kilometers (km) |
| --- | --- |
| 1 | 0.0003048 |
| 2 | 0.0006096 |
| 3 | 0.0009144 |
| 4 | 0.0012192 |
| 5 | 0.001524 |
| 6 | 0.0018288 |
| 7 | 0.0021336 |
| 8 | 0.0024384 |
| 9 | 0.0027432 |
| 10 | 0.003048 |
| 15 | 0.004572 |
| 20 | 0.006096 |
| 25 | 0.00762 |
| 30 | 0.009144 |
| 40 | 0.012192 |
| 50 | 0.01524 |
| 75 | 0.02286 |
| 100 | 0.03048 |
| 200 | 0.06096 |
| 250 | 0.0762 |
| 500 | 0.1524 |
| 1000 | 0.3048 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=ft&to_unit=km` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"ft","to_unit":"km"}`
- All length units: https://tttkmbb.com/api/v1/units?quantity=length · full converter: [Length Converter](https://tttkmbb.com/conversion/length.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many kilometers are in one foot?**

1 ft = 0.0003048 km. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert feet to kilometers?**

Multiply the value in feet by 0.0003048: kilometers = feet × 0.0003048. For example, 5 ft = 0.001524 km.

**How do I convert kilometers back to feet?**

Multiply by the inverse factor 3280.839895 (feet = kilometers × 3280.839895), or use the kilometers-to-feet page.

## Related conversions

- [Kilometers to feet](https://tttkmbb.com/conversion/km-to-feet.md) (reverse)
- [Kilometers to Miles](https://tttkmbb.com/conversion/km-to-miles.md)
- [Miles to Kilometers](https://tttkmbb.com/conversion/miles-to-km.md)
- [Meters to Feet](https://tttkmbb.com/conversion/meters-to-feet.md)
- [Feet to Meters](https://tttkmbb.com/conversion/feet-to-meters.md)
- [Centimeters to Inches](https://tttkmbb.com/conversion/cm-to-inches.md)
- [Inches to Centimeters](https://tttkmbb.com/conversion/inches-to-cm.md)
- [Millimeters to Inches](https://tttkmbb.com/conversion/mm-to-inches.md)
- [Inches to Millimeters](https://tttkmbb.com/conversion/inches-to-mm.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)