How to work out time as a percentage of a day or week
Time as a percentage = part of the time ÷ total time × 100, with both in the same unit. 8 hours is 33.3% of a day, 40 hours is 23.8% of a week, 45 minutes is 9.4% of an 8-hour workday.
Convert both amounts to the same unit, then divide. 8 hours of sleep is 8 ÷ 24 = 33.3% of a day. A 40-hour work week is 40 ÷ 168 = 23.8% of the week’s hours. A 45-minute meeting is 45 ÷ 480 = 9.4% of an 8-hour workday.
On this page
“What share of my day goes to commuting?” “How much of the week is spent in meetings?” Expressing time as a percentage is the usual part ÷ whole calculation, as long as both numbers are in the same unit.
The formula
time percentage = part of the time ÷ total time × 100
Where both are in the same unit (minutes, hours or days)
Hours of a day
8 hours of sleep out of 24:
Try it: 8 hours of 24
Open in calculatorThat’s 33.3%, a third of the day.
Hours of a week
A week has 7 × 24 = 168 hours. A 40-hour work week:
Try it: 40 hours of 168
Open in calculatorWork takes about 23.8% of all the hours in a week. Measured against waking hours only (168 − 56 hours of sleep = 112), it’s 35.7%.
Minutes of a workday
A 45-minute meeting in an 8-hour workday. Convert the day to minutes first: 8 × 60 = 480.
Try it: 45 minutes of 480
Open in calculatorAbout 9.4%. Mixing units, 45 ÷ 8, would give 562.5%, which is obviously wrong.
Useful totals
| Period | Hours | Minutes |
|---|---|---|
| Day | 24 | 1,440 |
| Workday (8 h) | 8 | 480 |
| Week | 168 | 10,080 |
| Year (365 days) | 8,760 | 525,600 |
Time elapsed vs work done
On a deadline, the share of time elapsed is useful to compare against progress. If a 6-week project is in week 3, 50% of the time has passed. If only 30% of the work is done, it’s behind schedule. See project completion percentage.
Planning with percentages
Percentages also work in reverse. If you want 10% of a 40-hour week for training, that’s 4 hours. Budgets of time work like budgets of money; compare the 50/30/20 budget.
For work time specifically, the utilization rate measures how much of the available hours go to target work.
Questions
How do I convert minutes to a decimal of an hour?
Divide by 60. 45 minutes is 0.75 hours, 20 minutes is 0.333 hours, and 6 minutes is 0.1 hours. This matters for timesheets, where 7 hours 45 minutes is 7.75 hours, not 7.45.
What share of a year is one day?
1 ÷ 365 ≈ 0.27%, or 1 ÷ 366 ≈ 0.27% in a leap year. One week is about 1.9% of a year, and one month is roughly 8.3%.
The calculator links in this guide are checked against the PercentSwift calculator every time the site is built. How we calculate explains the rounding rules. If you spot a mistake, email hello@percentswift.com.
