Weekly sleep shortfall

The calculator uses the numbers you enter: work-night sleep, weekend-night sleep, and the target. 6.5 minus 15 waking minutes is 6.25. Across 5 work nights and 2 weekend nights that is 9.3 hours short. Caffeine sits in the grid.

The target is the number you enter, not a medical dose. The calculator does not diagnose sleep and does not read a watch. Morning start: time from waking to work.

Input data

Enter the target, work-night sleep, weekend-night sleep, and wakings. You can leave caffeine after 14:00 blank.

Optional context

This field is optional. Caffeine after 14:00 appears in the grid beside the sleep hours. A blank field skips that context and does not change the main result.

Results

Enter data and click Calculate.

How it works

The calculator subtracts waking minutes divided by 60 from work-night and weekend-night sleep, then compares those remainders with the target. It multiplies the work-night difference by 5 and the weekend-night difference by 2. 6.5 − 0.25 = 6.25. (6.25 − 8) × 5 + (7.75 − 8) × 2 = −9.25, which is 9.3 hours below.

The main result comes from the target, work-night sleep, weekend-night sleep, and wakings. Caffeine after 14:00 sits in the grid and does not change the main result.

Second example: 7.5 versus 7.5 with no wakings is 0. Third: 5.5 minus 1 and 6 minus 1 versus 8 is 23.5 hours below.

The target is not a medical dose. A comma in 12.5 is read the same way as a period.

Formula

Result = (work-night − wakings ÷ 60 − target) × 5 + (weekend-night − wakings ÷ 60 − target) × 2. At 6.5, 8, 8, 1 and 15: (6.25 − 8) × 5 + (7.75 − 8) × 2 = −9.25, which is 9.3 hours below.

What these numbers mean

6.5 minus 0.25 and 8 minus 0.25 versus 8 is 9.3 hours below.

sleep shortfall
Sleep after wakings minus the target, then times 5 work nights and 2 weekend nights. At 6.25, 7.75 and 8 that is 9.3 hours below.
sleep target
The hours you set for one night. They are not a medical dose. In the first example they are 8.
wakings
Wakings a night times minutes of one waking, then divided by 60. That loss comes off both nights before the comparison with the target.

How to use

  1. Enter a target of 8, work-night sleep 6.5, and weekend-night sleep 8.
  2. Add 1 waking of 15 minutes.
  3. Click Calculate. The result is 9.3 hours below.
  4. Second example: 7.5, 7.5 and 7.5 with no wakings is 0. Third: 8, 5.5, 6, 3 and 20 is 23.5 hours below.
  5. You can skip caffeine after 14:00. When you fill it, it appears in the grid and does not change the main result.

Examples

Example 1

  • target 8 h
  • work night 6.5 h
  • weekend 8 h
  • wakings 1
  • waking 15 min

9.3 hours below

6.5 − 15 ÷ 60 = 6.25. (6.25 − 8) × 5 + (7.75 − 8) × 2 = −9.25, which is 9.3 hours below.

Example 2

  • target 7.5 h
  • work night 7.5 h
  • weekend 7.5 h
  • wakings 0
  • waking 10 min

0 hours versus the target

7.5 − 0 = 7.5. (7.5 − 7.5) × 5 + (7.5 − 7.5) × 2 = 0.

Example 3

  • target 8 h
  • work night 5.5 h
  • weekend 6 h
  • wakings 3
  • waking 20 min

23.5 hours below

5.5 − 3 × 20 ÷ 60 = 4.5. 6 − 1 = 5. (4.5 − 8) × 5 + (5 − 8) × 2 = −23.5.

Related calculators

Time from waking to work

Time from waking to work: 45 minus 40 times 5 over 60 is 0.4 hours above. Movement and breakfast sit in the grid.

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Short work breaks

Short work breaks: 8 times 60 over 45 minus 6 is 4.7 short breaks missing. Length and the longest stretch sit in the grid.

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Common questions

What does 9.3 hours below mean?

6.5 − 15 ÷ 60 = 6.25. (6.25 − 8) × 5 + (7.75 − 8) × 2 = −9.25, which is 9.3 hours below.

How is the result calculated?

Result = (work-night − wakings ÷ 60 − target) × 5 + (weekend-night − wakings ÷ 60 − target) × 2. At 6.5, 8, 8, 1 and 15 that is −9.25, which is 9.3 hours below.

What is the second example?

7.5 versus 7.5 with no wakings is 0.

What is the third example?

5.5 minus 1 and 6 minus 1 versus 8 is 23.5 hours below.

What does the calculator not do?

The calculator does not diagnose sleep and does not read a watch. Caffeine after 14:00 is optional.

Do all fields enter the main result?

No. The main result comes from the target, work-night sleep, weekend-night sleep, and wakings. Caffeine is optional.

What do sleep shortfall, target, and wakings mean?

The shortfall is sleep after wakings minus the target, then times 5 and 2 nights. The target is hours for one night. Wakings come off both nights before the comparison.

Does a comma in 12.5 work?

Yes. 12.5 and 12,5 are read the same way.

Sources

The result comes from the numbers you enter. This is spare time or a shortfall versus the sleep target, not a diagnosis.

Page updated in 2026.