Night Shift Recovery Calculator
The Night Shift Recovery Calculator gives a quick, rule-of-thumb read on the toll of a block of consecutive night shifts and roughly how long you might need to recover afterward. Enter how many nights you worked in a row and the shift length, and it returns the total night-shift hours, a guideline number of recovery days, and a rough estimate of how long your body clock takes to re-adjust to daytime.
Enter Values
How to use this calculator
- Enter the number of night shifts you worked back-to-back in the block (e.g. 7).
- Set the hours per night shift if it isn't the default 12.
- Read the total night-shift hours, the recommended minimum recovery days and the approximate circadian re-adjustment time.
How it works
Total night-shift hours is simply the number of nights multiplied by the hours per shift. The recovery-day guideline is a rule of thumb — about half the number of nights, rounded, and never fewer than two days: max(2, round(nights / 2)). The circadian estimate reflects that the body clock typically shifts back at roughly one day per hour of change, so re-adjusting to daytime commonly takes about 2–3 days. For 7 nights of 12 hours: 7 x 12 = 84 total hours, and max(2, round(7 / 2)) = max(2, 4) = 4 recovery days.
Worked example
Worked example. Seven 12-hour night shifts in a row add up to 84 night-shift hours. The guideline recovery is max(2, round(7 / 2)) = 4 days, and your body clock typically takes about 2–3 days to swing back to a daytime pattern.
Common mistakes
- Treating the recovery days as an entitlement or a fatigue standard — it is a general wellbeing guideline only, and your site's fatigue-management plan governs.
- Assuming recovery is instant after the last night: circadian re-adjustment usually takes a couple of days, so easing back into daytime helps.
- Ignoring cumulative fatigue — stacking blocks of nights with little rest between them compounds the toll well beyond a single block's estimate.
Frequently asked questions
Is this a fatigue-management standard?
No. It is a general wellbeing rule of thumb, not a regulated fatigue standard. Always follow your site's fatigue-management plan and, for driving, the National Heavy Vehicle Regulator (NHVR) fatigue rules.
Why is the minimum always at least two days?
Even a short block of nights disrupts your sleep and body clock, so the guideline floors recovery at two days. For longer blocks it scales up to about half the number of nights worked.
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- Sleep Debt Calculator
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- FIFO Pack Weight Calculator
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Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.