Weeks to Hours Converter
Convert weeks to hours — for project estimates, rosters and billable planning.
Updated
hours
168.00h
1 wk = 168.00 h
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In short
How many hours are in a week?
Exactly 168, from seven days of twenty-four. That is elapsed time. Available working time is a different figure: a 40-hour week is 0.238 of the calendar, so a four-week project has 672 hours of calendar and about 160 hours of one person's work in it.
Multiplying weeks by 168 answers "how long"; multiplying by 40 answers "how much work fits". Mixing them is the classic estimating error.
weeks to hours — quick reference
| weeks (wk) | hours (h) |
|---|---|
| 1 wk | 168.00 h |
| 2 wk | 336.00 h |
| 4 wk | 672.00 h |
| 8 wk | 1,344.00 h |
| 13 wk | 2,184.00 h |
| 26 wk | 4,368.00 h |
| 39 wk | 6,552.00 h |
| 52 wk | 8,736.00 h |
The formula, worked line by line
Both ratios are exact and neither is an average. A day is 24 hours and a week is 7 days, so a week is 168 hours with nothing to round. This is one of the cleanest conversions in the whole time family.
“A week is seven days; a day is twenty-four hours. Neither ratio has an exception in civil timekeeping, apart from the two local clock-change days a year.”
The exception is local rather than arithmetic. Where daylight saving is observed, one week a year runs 167 hours between local midnights and one runs 169. Anything computed in UTC is unaffected.
hours = weeks x 168
168 = 7 x 24
1 week -> 1 x 168 = 168 h
1 week = 168 h = 10,080 min = 604,800 s
person-hours = weeks x contracted week, usually 35 to 40- Weeks entered
- 1
- Hours per week
- 168, exactly
- Multiplication
- 1 x 168 = 168
- Hours
- 168.00 h
That is elapsed time. The same week yields about 40 hours of one person's work, 80 for a pair, and rather less than either once holidays, meetings and the limits of sustained concentration are taken out.
Where the 2,080-hour year comes from
It is 40 multiplied by 52 and nothing more. It appears throughout salary arithmetic because dividing an annual figure by 2,080 gives a nominal hourly rate, and it deliberately ignores that a year is 52.1775 weeks and that nobody works every one of them.
- Gregorian year, elapsed
- 8,765.82 h
- 52 weeks at 40 hours
- 2,080 h
- Less public holidays, say 8 days
- -64 h
- Less 20 days of leave
- -160 h
- Realistic available year
- about 1,856 h
The leave and holiday figures vary by country and contract. The point is the shape: available time is roughly a fifth of elapsed time, not a quarter.
Two clock-change weeks a year
In jurisdictions that observe daylight saving, the spring week is 167 hours between local midnights and the autumn week is 169. It matters for payroll computed from local timestamps and for anything billed by elapsed local hours; it does not matter for UTC arithmetic.
How to use the weeks to hours converter
A week is exactly 168 hours, because a day is 24 hours and a week is 7 days, and both ratios are definitions. Multiplying weeks by 168 is therefore exact — one of the few time conversions with no average anywhere in it and nothing to round.
What the number means is the harder part. One hundred and sixty-eight hours is how much time passes, not how much work is available. Those two figures differ by a factor of about 4.2 for a single person on a standard contract, and quoting the wrong one turns a plan into fiction.
168 h
One calendar week
elapsed time
40 h
One working week, per person
the US convention
4.2x
The gap between them
calendar against capacity
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For a schedule the calendar figure is the constraint and the working figure is the resource. A four-week window contains 672 hours of calendar. If one person is doing the work at 40 hours a week, only about 160 of those hours are actually available, and the other 512 are evenings, weekends and sleep.
Where the calendar figure earns its keep is anything that runs unattended. A process, a soak test, a cure time, a fermentation or a rental all consume elapsed hours regardless of who is awake, and for those 168 per week is exactly the right multiplier.
- 1 week
- 168 h elapsed, 40 h of work
- 2 weeks
- 336 h elapsed, 80 h of work
- 4 weeks
- 672 h elapsed, 160 h of work
- 13 weeks, a quarter
- 2,184 h elapsed, 520 h of work
- 26 weeks
- 4,368 h elapsed, 1,040 h of work
- 52 weeks
- 8,736 h elapsed, 2,080 h of work
The 2,080-hour figure in the last row is the conventional American working year, and it is simply 40 multiplied by 52.
Counting the days people actually work
Calendar weeks include weekends and holidays. That page counts the real working days between two dates, which is the number a delivery estimate should be built on.
Open the working days calculator →Weeks converted to hours, with the equivalent in 40-hour working weeks and the person-hours available. The second and third columns are conventions, not calendar facts.
| Weeks | Hours elapsed | Person-hours at 40/wk |
|---|---|---|
| 1 week | 168 h | 40 h |
| 2 weeks | 336 h | 80 h |
| 3 weeks | 504 h | 120 h |
| 4 weeks | 672 h | 160 h |
| 6 weeks | 1,008 h | 240 h |
| 8 weeks | 1,344 h | 320 h |
| 12 weeks | 2,016 h | 480 h |
| 13 weeks | 2,184 h | 520 h |
| 26 weeks | 4,368 h | 1,040 h |
| 39 weeks | 6,552 h | 1,560 h |
| 52 weeks | 8,736 h | 2,080 h |
| 104 weeks | 17,472 h | 4,160 h |
| 520 weeks | 87,360 h | 20,800 h |
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Elapsed time against available time
Every schedule contains both quantities and they are easy to confuse because both are measured in hours. Elapsed hours are what the calendar spends. Available hours are what a person can contribute. A plan that needs 300 hours of work in a two-week window is asking one person for 300 out of 80.
The failure mode is not usually that bad. It is subtler: an estimate given in hours, read as elapsed time by whoever receives it, and turned into a delivery date that assumes the work runs continuously. Nothing in the number itself signals which kind of hour it was.
- As elapsed hours
- 1.19 calendar weeks
- As one person at 40 h a week
- 5 working weeks
- As two people at 40 h a week
- 2.5 working weeks
- Calendar time for the one-person plan
- about 5 weeks, or 840 hours
- Spread between readings
- a week against five
Both readings come from the same 200 and they differ by a factor of four. The habit that prevents this is stating the unit every time: "200 person-hours" and "200 hours of elapsed time" are unambiguous where "200 hours" is not.
Adding people does not scale the calendar down cleanly either, because coordination costs rise and some work cannot be parallelised at all. The conversion on this page is exact; what a schedule does with it is where the judgement lives.
The year in hours, both kinds
Fifty-two weeks is 8,736 hours. A Gregorian year is 8,765.82, because a year is 52.1775 weeks rather than 52. The 29.82-hour gap is the same day and a quarter that makes 52 weeks fall short of a year, expressed in hours instead of days.
The working year is a different figure entirely and is conventionally 2,080 hours: forty hours multiplied by fifty-two weeks. That number appears in salary arithmetic constantly, because dividing an annual salary by 2,080 gives the nominal hourly rate.
- 52 weeks in hours
- 8,736 h
- A Gregorian year in hours
- 8,765.82 h
- The difference
- 29.82 h, about 1.24 days
- A conventional working year
- 2,080 h, 40 x 52
Only the last row is a convention. The first three are calendar arithmetic and none of them is negotiable.
Subtract holidays and leave from the 2,080 and a realistic available year is nearer 1,800 to 1,900 hours for one person. That is the figure worth planning capacity against, and it is roughly a fifth of the calendar year rather than a quarter.
Every weeks value, worked out
61 common weeks figures each get their own page, with the answer at full precision, the arithmetic, what rounding costs, and the nearest real-world reference point on the scale.
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Questions people ask
How many hours are in a week?
Exactly 168, from seven days of twenty-four hours. Both ratios are definitions, so nothing rounds. That figure is elapsed time. A working week is a separate, contractual number — conventionally 40 hours in the United States and 35 to 40 across much of Europe — and the two differ by a factor of about 4.2.
How many hours are in 2 weeks?
336 hours of elapsed time, or 80 person-hours if one person is working a 40-hour week. The gap between those two readings is what makes two-week estimates go wrong: a job needing 200 hours of work does not fit into a fortnight for one person, even though 336 is comfortably more than 200.
How many hours are in a year?
8,765.82 on the Gregorian mean year, or 8,736 if you count 52 weeks. The 29.82-hour difference is the same day and a quarter by which 52 weeks falls short of a full year. The conventional working year is 2,080 hours, which is simply 40 multiplied by 52 and ignores both leave and the extra day.
How many hours are in 4 weeks?
672 hours of elapsed time and 160 person-hours at a 40-hour week. Four weeks is also 28 days, which is not quite a month — the average month is 30.44 days, so a four-week sprint is about 8 percent shorter than a calendar month and the difference compounds over a year.
Why do project estimates in hours go wrong?
Usually because an estimate given in person-hours is read as elapsed hours. Two hundred hours is 1.19 calendar weeks and five working weeks for one person, and nothing in the number itself says which was meant. Writing "person-hours" or "elapsed hours" every time removes the ambiguity at no cost.
Sources
Where the constants and formulas on this page come from. Each line names the figure it backs.
The FLSA requires overtime pay above 40 hours in a workweek for covered non-exempt employees, and sets no maximum weekly hours for adults.
Overtime Pay — Fair Labor Standards Act — US Department of Labor, Wage and Hour Division
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