How is standard time calculated?

Standard time is the mean observed time times the performance rating, times one plus the allowance. An element averaging 4.8 seconds rated at 95 percent has a normal time of 4.56 seconds; with a 12 percent PF&D allowance its standard time is 5.11 seconds. Machine-controlled elements are not rated and get no allowance, because the operator does not set their pace.

How many cycles should I time?

The workbook works it out per element with the textbook formula for 95 percent confidence and plus or minus 5 percent precision: (40 times the square root of n times the sum of squares minus the square of the sum, divided by the sum) squared. An element whose readings vary by about 5 percent needs about 4 cycles; one that varies by 10 percent needs about 16. The Check column says Study more cycles when you have timed fewer than needed.

What PF&D allowance should I use?

That is your decision, and the workbook does not assume one. Personal, fatigue and delay allowances depend on the work, the environment and local agreements; work-study handbooks such as the ILO's Introduction to Work Study discuss how to set them. Type your value on Setup and it applies to every manual and walk element.

What is SAM and how does the template show it?

SAM, standard allowed minutes, is the apparel industry's name for the standard time of an operation in minutes. The Dashboard shows the standard cycle divided by 60; a 47.2 second cycle is 0.787 standard minutes per unit.

Why does the standard cycle add machine time to manual time?

The workbook, like the Standard Work Combination calculator, assumes elements run one after another, so the operator waits while the machine runs. Where the operator can work during the machine cycle, the real cycle is shorter, and the combination chart shows exactly where that overlap could be found. Re-time the new method and the standard cycle drops.

Can I use this for operations without a machine?

Yes. Mark every element Manual or Walk. Sewing, hand assembly and packing operations work the same way: readings, ratings and the allowance give the standard time, and the Dashboard compares it with takt.

Production and Throughput

Time Study and Standard Work Excel Template

Turn stopwatch readings into normal and standard times per element, check whether you timed enough cycles, and compare the standard work combination with takt time.

Overview

This time study and standard work workbook is for industrial engineers, lean practitioners, team leaders and apparel production engineers who need a standard time they can defend. It ships with a fictional valve maker's study of an assembly and leak-test station, ten elements timed over ten cycles, so every calculation and chart is filled in the moment you open it.

For each element the workbook takes the mean of the readings, multiplies it by the performance rating to get normal time (machine-controlled elements are not rated), and adds your personal, fatigue and delay allowance to manual and walk elements to get standard time. It also works out how many cycles a 95 percent confidence, plus or minus 5 percent study needs, using the classic sample-size formula from work-study textbooks, and the Check column tells you when you timed too few. Summed in work order, the standard times give the standard cycle and the standard minutes per unit; manual plus walk time is the operator's work, and both are compared with takt time, as in the Standard Work Combination calculator on this site.

In the example the standard cycle is 47.2 seconds against a 45 second takt, so the station cannot meet demand as designed. The combination chart shows why: the operator waits 12 seconds for the leak tester. Walking back to the start and picking the next housing during the test would bring the cycle under takt, the kind of change a standard work sheet is meant to reveal.

What this template includes

Study table, one row per work element: type (Manual, Machine or Walk), up to ten stopwatch readings in seconds and a performance rating
Per element: mean, minimum and maximum, normal time, allowance, standard time and where the element starts in the cycle
Cycles needed for 95 percent confidence and plus or minus 5 percent precision, per element, with the Check column saying when to study more cycles
Check column that names study problems in words: fewer than three readings, an outlier reading, a rating typed on a machine element, a duplicate element number
Takt time from available time and demand per shift, and one PF&D allowance you set on Setup
Dashboard with standard cycle against takt, gap to takt, operator utilisation and standard minutes per unit (SAM)
Two native charts: a standard work combination chart of manual, machine and walk time in work order, and the observed cycle time by cycle against takt
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference (Self-check: PASS)

Suggested use case

Use it to set a standard time for a new or changed operation, to check whether a station can meet takt before you balance a line, or to set standard allowed minutes for a sewing or assembly operation.

How to use it

On Setup, type the operation, the available minutes and demand per shift, and your PF&D allowance.
On Study, break the operation into elements with clear start and end points, in work order, and give each a type.
Time ten cycles and type each reading in seconds; rate each manual and walk element against normal pace.
Read the Check column and time more cycles for any element that needs them.
Open the Dashboard to compare the standard cycle with takt and see which elements take the time.

Frequently Asked Questions

How is standard time calculated?: Standard time is the mean observed time times the performance rating, times one plus the allowance. An element averaging 4.8 seconds rated at 95 percent has a normal time of 4.56 seconds; with a 12 percent PF&D allowance its standard time is 5.11 seconds. Machine-controlled elements are not rated and get no allowance, because the operator does not set their pace.
How many cycles should I time?: The workbook works it out per element with the textbook formula for 95 percent confidence and plus or minus 5 percent precision: (40 times the square root of n times the sum of squares minus the square of the sum, divided by the sum) squared. An element whose readings vary by about 5 percent needs about 4 cycles; one that varies by 10 percent needs about 16. The Check column says Study more cycles when you have timed fewer than needed.
What PF&D allowance should I use?: That is your decision, and the workbook does not assume one. Personal, fatigue and delay allowances depend on the work, the environment and local agreements; work-study handbooks such as the ILO's Introduction to Work Study discuss how to set them. Type your value on Setup and it applies to every manual and walk element.
What is SAM and how does the template show it?: SAM, standard allowed minutes, is the apparel industry's name for the standard time of an operation in minutes. The Dashboard shows the standard cycle divided by 60; a 47.2 second cycle is 0.787 standard minutes per unit.
Why does the standard cycle add machine time to manual time?: The workbook, like the Standard Work Combination calculator, assumes elements run one after another, so the operator waits while the machine runs. Where the operator can work during the machine cycle, the real cycle is shorter, and the combination chart shows exactly where that overlap could be found. Re-time the new method and the standard cycle drops.
Can I use this for operations without a machine?: Yes. Mark every element Manual or Walk. Sewing, hand assembly and packing operations work the same way: readings, ratings and the allowance give the standard time, and the Dashboard compares it with takt.