Standard Time Calculator (Time Study: Normal Time, Rating and Allowances)
Normal and standard time per cycle from the observed time, the operator's performance rating and the allowance, with the output per hour that standard allows.
Results
What this tool does
In a time study the stopwatch time is first adjusted by the operator's pace rating — 100 means the normal pace, 110 means ten per cent faster than normal — giving the normal time, the time a typical worker would take. Allowances for fatigue, personal needs and unavoidable delays are then added to give the standard time. Textbooks use two conventions: adding the percentage to the normal time, or treating it as a share of the whole working time, which divides by (1 − A) and gives a slightly longer standard time. Both are in use, so state which one you apply.
Formula
normal time = observed × rating ÷ 100 · standard = normal × (1 + A) or normal ÷ (1 − A)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
ot | Observed average time per cycle | min |
pr | Performance rating of the operator (100 = normal pace) | % |
al | Allowance for fatigue, personal needs and delays | % |
md | The allowance is a percentage of | — |
ST | Standard time per cycle | min |
NT | Normal time per cycle | min |
AT | Allowance time inside each cycle | min |
PH | Output per hour at the standard time | /h |
Worked example
- Observed average time per cycle1.25 min
- Performance rating of the operator (100 = normal pace)110 %
- Allowance for fatigue, personal needs and delays15 %
- The allowance is a percentage of1
- Standard time per cycle1.581 min
- Normal time per cycle1.375 min
- Allowance time inside each cycle0.206 min
- Output per hour at the standard time37.9 /h
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.