# Days to Weeks (d to wk)

> Convert days to weeks: 1 d = 0.142857 wk. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `days-to-weeks` · Quantity: Time (`time`, base unit s) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/days-to-weeks · This document: https://tttkmbb.com/conversion/days-to-weeks.md · JSON: https://tttkmbb.com/conversion/days-to-weeks.json (add `?value=` for a result)

## Formula

- `1 d = 0.142857 wk`
- `weeks = days × 0.1428571429`
- Reverse: `days = weeks × 7`

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 d = 0.714286 wk
- 12.5 d = 1.78571 wk
- 100 d = 14.2857 wk

## Conversion table

| Days (d) | Weeks (wk) |
| --- | --- |
| 1 | 0.142857 |
| 2 | 0.285714 |
| 3 | 0.428571 |
| 4 | 0.571429 |
| 5 | 0.714286 |
| 6 | 0.857143 |
| 7 | 1 |
| 8 | 1.14286 |
| 9 | 1.28571 |
| 10 | 1.42857 |
| 15 | 2.14286 |
| 20 | 2.85714 |
| 25 | 3.57143 |
| 30 | 4.28571 |
| 40 | 5.71429 |
| 50 | 7.14286 |
| 75 | 10.7143 |
| 100 | 14.2857 |
| 200 | 28.5714 |
| 250 | 35.7143 |
| 500 | 71.4286 |
| 1000 | 142.857 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=day&to_unit=week` → 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":"day","to_unit":"week"}`
- All time units: https://tttkmbb.com/api/v1/units?quantity=time · full converter: [Time Converter](https://tttkmbb.com/conversion/time.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many weeks are in one day?**

1 d = 0.142857 wk. 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 days to weeks?**

Multiply the value in days by 0.1428571429: weeks = days × 0.1428571429. For example, 5 d = 0.714286 wk.

**How do I convert weeks back to days?**

Multiply by the inverse factor 7 (days = weeks × 7), or use the weeks-to-days page.

## Related conversions

- [Weeks to days](https://tttkmbb.com/conversion/weeks-to-days.md) (reverse)
- [Hours to Minutes](https://tttkmbb.com/conversion/hours-to-minutes.md)
- [Minutes to Hours](https://tttkmbb.com/conversion/minutes-to-hours.md)
- [Minutes to Seconds](https://tttkmbb.com/conversion/minutes-to-seconds.md)
- [Seconds to Minutes](https://tttkmbb.com/conversion/seconds-to-minutes.md)
- [Days to Hours](https://tttkmbb.com/conversion/days-to-hours.md)
- [Hours to Days](https://tttkmbb.com/conversion/hours-to-days.md)
- [Years (365 days) to Days](https://tttkmbb.com/conversion/years-to-days.md)
- [Days to Years (365 days)](https://tttkmbb.com/conversion/days-to-years.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)