What this calculator does
A week is a fixed seven days, so converting between the two is a single division or multiplication. This is handy for anything measured in a run of days that reads more naturally in weeks, such as how many weeks is 90 days, a course length, a notice period, or a recovery timeframe given by a doctor.
The tricky part is not the arithmetic but the remainder. Ninety days is not a tidy number of weeks: it comes out to 12 weeks and 6 days, not exactly 13 weeks. This calculator gives you the exact decimal figure alongside the whole number of weeks and whatever days are left over, so nothing gets rounded away by accident.
The formula
Divide the number of days by seven to get weeks, or multiply weeks by seven to get days. The whole-weeks figure is that division rounded down, with the remainder shown separately as leftover days.
| Term | Meaning |
|---|---|
| Weeks | Days divided by seven, expressed as a decimal. |
| Whole weeks | The number of complete seven-day weeks, ignoring any leftover days. |
| Remaining days | What is left over after removing the whole weeks, always less than seven. |
The inputs explained
| Field | What to enter |
|---|---|
| Value | The number of days or weeks you want to convert, depending on the direction chosen below. |
| Convert | Choose whether you are converting days into weeks or weeks back into days. |
When to use it
Reading a notice or waiting period
Contracts and government processes often state a period in days, such as a 90 day notice period. Converting that to weeks makes it easier to picture on a calendar or diary.
Following medical or recovery guidance
A recovery timeframe given as a number of days is easier to plan around once you know how many whole weeks that spans, and how many extra days sit on top.
Planning a course or project length
A course or sprint quoted in weeks converts straight to a day count for scheduling, without needing to count out a calendar by hand.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How many weeks are common day counts?
A spread of common day counts, converted to weeks.
| Days | Weeks | Whole weeks | Remaining days |
|---|---|---|---|
| 7 days | 1.000 | 1 | 0 |
| 14 days | 2.000 | 2 | 0 |
| 30 days | 4.286 | 4 | 2 |
| 60 days | 8.571 | 8 | 4 |
| 90 days | 12.857 | 12 | 6 |
| 100 days | 14.286 | 14 | 2 |
| 180 days | 25.714 | 25 | 5 |
| 365 days | 52.143 | 52 | 1 |
How many days are common week counts?
A spread of common week counts, converted to days.
Questions
How many weeks is 90 days?
90 days is 12 whole weeks plus 6 remaining days, or 12.86 weeks expressed as a decimal. It does not divide evenly, since 90 is not a multiple of seven.
Is a month always four weeks?
No. Four weeks is only 28 days, while most calendar months run 30 or 31 days, and February is 28 or 29. Treating a month as exactly four weeks understates it by two or three days most of the year.
Why is the weeks figure a decimal rather than a whole number?
Because most day counts are not exact multiples of seven. The decimal weeks figure is the precise value; the whole-weeks and remaining-days figures split that same value into a more calendar-friendly form.
Does this account for different month lengths?
No, this conversion is a fixed seven-day week, independent of calendar months. For a month-based conversion instead, see the days to months calculator.
For a month-based version of this conversion, see the Days to Months Calculator. For longer spans, the Weeks to Years Converter takes weeks up to years.