3 wk to d — 3 weeks in days

3wk21d

Exact 3 × 7 = 21

3 weeks in other units

Nanoseconds1,814,400,000,000,000ns
Microseconds1,814,400,000,000µs
Milliseconds1,814,400,000ms
Seconds1,814,400s
Minutes30,240min
Hours504h
Days21d
Months0.68995257mo
Years0.05749605yr

wk to d at a glance

WeeksDays
1 wk7 d
2 wk14 d
3 wk21 d
5 wk35 d
10 wk70 d
20 wk140 d
25 wk175 d
50 wk350 d
100 wk700 d
250 wk1,750 d
500 wk3,500 d
1,000 wk7,000 d

How to convert weeks to days

Multiply by 7 — one week is 7 days. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.

Working 3 × 7 = 21

In words: twenty-one days.

What these units are

The week and the day are covered in the time unit guide, along with every other unit on this page.

Questions

How many days are in a week?

One week is 7 days. This figure is exact — it comes from the definition of the unit, not a measurement.

What is 3 weeks in days?

3 weeks is 21 days. The working is 3 × 7 = 21.

How many seconds are in a year?

About 31.56 million — but there is no single right answer. A common year of 365 days holds 31,536,000 seconds and a leap year holds 31,622,400. This page uses the Gregorian average of 365.2425 days, or 31,556,952 seconds, which is the figure that keeps the calendar aligned over centuries.

Why are months and years marked as not exact?

Because they are averages, and everything else on this page is a definition. Sixty seconds make a minute always. A month is somewhere between 28 and 31 days depending on which one you mean, so any single number for it is a convention rather than a fact.

How do I convert a duration into days, hours and minutes?

Enter it in any unit and the breakdown line underneath the result does it — 10,000 seconds comes out as 2 hours 46 minutes 40 seconds. Only exact units appear there, so a long duration is given in weeks and days rather than being rounded into notional months.

Is a day always 86,400 seconds?

As a unit, yes. As an actual rotation of the Earth, not quite — the planet's spin drifts, which is why leap seconds have occasionally been added to civil time. The unit stays fixed at 86,400 seconds and the calendar absorbs the difference.

Other time conversions

More conversions