# Weeks to Days (wk to d)

> Convert weeks to days: 1 wk = 7 d. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

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

## Formula

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

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 wk = 35 d
- 12.5 wk = 87.5 d
- 100 wk = 700 d

## Conversion table

| Weeks (wk) | Days (d) |
| --- | --- |
| 1 | 7 |
| 2 | 14 |
| 3 | 21 |
| 4 | 28 |
| 5 | 35 |
| 6 | 42 |
| 7 | 49 |
| 8 | 56 |
| 9 | 63 |
| 10 | 70 |
| 15 | 105 |
| 20 | 140 |
| 25 | 175 |
| 30 | 210 |
| 40 | 280 |
| 50 | 350 |
| 75 | 525 |
| 100 | 700 |
| 200 | 1400 |
| 250 | 1750 |
| 500 | 3500 |
| 1000 | 7000 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=week&to_unit=day` → 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":"week","to_unit":"day"}`
- 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 days are in one week?**

1 wk = 7 d. 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 weeks to days?**

Multiply the value in weeks by 7: days = weeks × 7. For example, 5 wk = 35 d.

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

Multiply by the inverse factor 0.1428571429 (weeks = days × 0.1428571429), or use the days-to-weeks page.

## Related conversions

- [Days to weeks](https://tttkmbb.com/conversion/days-to-weeks.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)