Quick answer
Hours for an activity = total hours × its percentage ÷ 100. A 40-hour week split 50/25/15/10 gives 20, 10, 6 and 4 hours with nothing unallocated.
Enter total hours and a percentage for each activity. The calculator returns hours per activity and what is unallocated. Use this time allocation calculator to check your own figures.
Related tools: Time Blocking Calculator: Lay tasks back to back from a start time, with a buffer between blocks. Time Saved Calculator: Hours saved over a year by speeding up a task. Time Card Calculator: Total hours, overtime and gross pay from daily start and end times.
How to use the Time Allocation Calculator
- Enter total time (hours) (0.01 or more).
- Enter activity 1 (%) (between 0 and 100).
- Enter activity 2 (%) (between 0 and 100). It starts at 0.
- Enter activity 3 (%) (between 0 and 100). It starts at 0.
- Enter activity 4 (%) (between 0 and 100). It starts at 0.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Total time (hours) | A number | ≥ 0.01 |
| Activity 1 (%) | A number | ≥ 0, ≤ 100 |
| Activity 2 (%) | A number | ≥ 0, ≤ 100, starts at 0 |
| Activity 3 (%) | A number | ≥ 0, ≤ 100, starts at 0 |
| Activity 4 (%) | A number | ≥ 0, ≤ 100, starts at 0 |
Formula and method
Formula
hours for an activity = total hours × its percentage ÷ 100; unallocated = total − sum
IEEE-754 double precision; shown to at most 6 decimal places.
Turns percentage shares of your time into hours and minutes. The shares may add to less than 100% (the rest is shown as unallocated) but not more.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Total time (hours) = 40; Activity 1 (%) = 50; Activity 2 (%) = 25; Activity 3 (%) = 15; Activity 4 (%) = 10.
| Result | Value |
|---|---|
| Activity 1 | 20 h (20 h 0 min) |
| Activity 2 | 10 h (10 h 0 min) |
| Activity 3 | 6 h (6 h 0 min) |
| Activity 4 | 4 h (4 h 0 min) |
| Unallocated | 0 h (0 h 0 min) |
Example 2
Inputs: Total time (hours) = 10; Activity 1 (%) = 60; Activity 2 (%) = 0; Activity 3 (%) = 0; Activity 4 (%) = 0.
| Result | Value |
|---|---|
| Activity 1 | 6 h (6 h 0 min) |
| Activity 2 | 0 h (0 h 0 min) |
| Activity 3 | 0 h (0 h 0 min) |
| Activity 4 | 0 h (0 h 0 min) |
| Unallocated | 4 h (4 h 0 min) |
Example 3
Inputs: Total time (hours) = 7.5; Activity 1 (%) = 33.3; Activity 2 (%) = 33.3; Activity 3 (%) = 0; Activity 4 (%) = 0.
| Result | Value |
|---|---|
| Activity 1 | 2.5 h (2 h 30 min) |
| Activity 2 | 2.5 h (2 h 30 min) |
| Activity 3 | 0 h (0 h 0 min) |
| Activity 4 | 0 h (0 h 0 min) |
| Unallocated | 2.51 h (2 h 30 min) |
The first line is the headline result (activity 1). Below it the time Allocation Calculator lists activity 2, activity 3, activity 4 and unallocated, which describe the same case from other angles. IEEE-754 double precision; shown to at most 6 decimal places.
Check
50 + 25 + 15 + 10 = 100%. If shares total less than 100, the rest shows as unallocated.
Where this estimate stops applying
Shares may not add to more than 100%. Revisit the split weekly.
How the result changes with total time
Holding every other input at the first worked example, this table changes only total time. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Total time | Activity 1 | Activity 2 | Activity 3 |
|---|---|---|---|
| 20 | 10 h (10 h 0 min) | 5 h (5 h 0 min) | 3 h (3 h 0 min) |
| 40 | 20 h (20 h 0 min) | 10 h (10 h 0 min) | 6 h (6 h 0 min) |
| 80 | 40 h (40 h 0 min) | 20 h (20 h 0 min) | 12 h (12 h 0 min) |
| 160 | 80 h (80 h 0 min) | 40 h (40 h 0 min) | 24 h (24 h 0 min) |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Total time (hours): left empty shows "Enter total time (hours)." beside that field and no result.
- Activity 1 (%): entering "60" shows "The percentages add up to more than 100%." beside that field and no result.
Choosing between the Time Allocation Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Time Blocking Calculator](/time/time-blocking-calculator/) | task durations in minutes, separated by commas, start time and buffer between blocks | Finish time |
| [Time Saved Calculator](/lifestyle/time-saved-calculator/) | times the task is done per day, minutes saved each time and working days per year | Time saved per year |
| [Time Card Calculator](/time/time-card-calculator/) | start times, end times and unpaid break per day | Total time |
| [Time From Now Calculator](/time/minutes-from/) | start time and minutes to add | Resulting time |
| [Average Time Calculator](/time/average-time-calculator/) | times to average | Average time |
Background: dates and times
Date and time results depend on the conventions a tool uses: whether the end date counts, whether weekends and holidays are skipped, how months of different lengths are handled and whether time zones are applied. This page states its convention, and the worked examples show it.
Dates use the Gregorian calendar and calendar days unless the page says otherwise; check deadlines against the rule in your contract or regulation.
Assumptions and limitations
- Shares may not add to more than 100%
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for total time (hours) and activity 1 (%) to confirm this.
Frequently asked questions
What if I allocate 110%?
Allocations over 100% are rejected, since they would give more hours than the total available.
Can I include breaks?
Yes, as an activity.
How do I convert to minutes?
Multiply hours by 60.
What does the Time Allocation Calculator calculate?
Split a block of time between activities by percentage. It returns Activity 1, Activity 2, Activity 3, Activity 4 and Unallocated.
What formula does the Time Allocation Calculator use?
hours for an activity = total hours × its percentage ÷ 100; unallocated = total − sum. Turns percentage shares of your time into hours and minutes.
What do I need to enter in the time Allocation Calculator?
You enter Total time (hours), Activity 1 (%), Activity 2 (%), Activity 3 (%) and Activity 4 (%).
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Shares may not add to more than 100%.
What is an example of a time Allocation result?
With total time (hours) 40, activity 1 (%) 50, activity 2 (%) 25, activity 3 (%) 15 and activity 4 (%) 10, the activity 1 is 20 h (20 h 0 min).
Related calculators
- Time Blocking Calculator — Lay tasks back to back from a start time, with a buffer between blocks.
- Time Saved Calculator — Hours saved over a year by speeding up a task.
- Time Card Calculator — Total hours, overtime and gross pay from daily start and end times.
- Time From Now Calculator — Clock time after adding or subtracting minutes.
- Average Time Calculator — Average of several durations.
- Focus Session (Pomodoro) Calculator — How many focus sessions and breaks fit in the time you have.
Sources
- NIST Special Publication 811, Guide for the Use of the International System of Units (SI): minute, hour and day are non-SI units accepted for use with the SI (60 min = 1 h, 24 h = 1 d)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.