Days to Weeks Converter
Convert days to weeks for project planning, PTO tracking, and deadline scheduling in US workplaces.
How It Works
Formula: d to wk = value × 0.1428571
Example: 14 d = 1.999999 wk
Note: 1 week equals exactly 7 calendar days.
Common Uses
Quick Conversion Table
| d | wk |
|---|---|
| 1 | 0.1429 |
| 5 | 0.7143 |
| 10 | 1.4286 |
| 50 | 7.1429 |
| 100 | 14.2857 |
| 500 | 71.4285 |
| 1000 | 142.8571 |
Rounding Rule
Rounded to 4 decimal places
Error Margin
±0.0001 wk
Precision Guidance
For planning, round to 2 decimals. For payroll, use exact day counts.
Common Mistakes
A "work week" of 5 days differs from a 7-day calendar week. Confirm which the task expects.
Frequently Asked Questions
How many days are in a week?
A calendar week has exactly 7 days, so days ÷ 7 = weeks.
How do I convert 21 days to weeks?
Divide 21 by 7: 21 days = 3 weeks.
Does this count business days?
No. This is a calendar-day conversion. For working days excluding weekends and US federal holidays, use a business-day calculator.
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Exact Constants & Authoritative Sources
Every conversion on this page uses the fixed, internationally agreed constants below — drawn from NIST and the SI Brochure. No values are estimated or rounded as if exact. See the full list on our Sources & Standards page.
- EXACT1 inch (in) = 25.4 millimetres (exact)
- EXACT1 foot (ft) = 0.3048 metres (exact, 12 in)
- EXACT1 yard (yd) = 0.9144 metres (exact, 3 ft)
- EXACT1 mile (mi) = 1609.344 metres (exact, 5280 ft)
- EXACT1 centimetre (cm) = 0.01 metre (definition)
Common Pitfalls & How to Avoid Them
US survey foot is deprecated
The old US survey foot (0.304800609601 m) was retired in 2023 in favor of the international foot (0.3048 m). Modern conversions use the international foot; mixing them drifts over long distances.
Inches vs. centimetres for screens
Display and wheel sizes are often rounded to the nearest convenient number; a "27-inch" monitor is nominal, not a precise 68.58 cm panel.
A unit-conversion reference site has no manufacturer-specific or device calibration parameters, so "layered tuning" does not apply here. The only real error-handling is input validation: the converter rejects non-numeric, empty, or out-of-range entries and shows a clear message, then falls back to exact constants above. No estimated or rounded figures are ever presented as exact.
Authoritative sources for this page
- NIST (U.S. National Institute of Standards and Technology) — NIST SP 330 — The International System of Units (SI), 2019 edition
- BIPM (International Bureau of Weights and Measures) — SI Brochure — The International System of Units (9th edition)
Last Updated 2026 | This converter was reviewed for accuracy