Sewing line efficiency calculator
How many standard minutes the line earned, compared with the minutes its operators were available. The definition of 'available' is stated, so the result can be compared with your own reports.
How this is calculated
earned minutes = good pieces × SMV and available minutes = operators × working minutes. Efficiency is earned ÷ available × 100. Working minutes are paid attendance on the line, excluding scheduled breaks.
If you enter off-standard operator-minutes, the calculator also reports on-standard efficiency = earned ÷ (available − off-standard) × 100.
Worked example. 30 operators work 480 minutes and produce 600 good pieces of a 12-minute garment. Earned minutes = 600 × 12 = 7,200. Available minutes = 30 × 480 = 14,400. Efficiency = 7,200 ÷ 14,400 = 50.0%. With 720 operator-minutes of recorded breakdown, on-standard efficiency is 7,200 ÷ 13,680 = 52.6%.
Quick table: line efficiency for a 30-operator, 8-hour shift
Overall efficiency (%) for 30 operators working 480 minutes (14,400 available minutes) across common daily outputs and garment SMVs.
| Daily output | SMV 8 | SMV 10 | SMV 12 | SMV 15 | SMV 18 |
|---|---|---|---|---|---|
| 450 pcs | 25.0% | 31.3% | 37.5% | 46.9% | 56.3% |
| 600 pcs | 33.3% | 41.7% | 50.0% | 62.5% | 75.0% |
| 720 pcs | 40.0% | 50.0% | 60.0% | 75.0% | 90.0% |
| 840 pcs | 46.7% | 58.3% | 70.0% | 87.5% | 105.0% |
| 960 pcs | 53.3% | 66.7% | 80.0% | 100.0% | 120.0% |
Questions
- Which operators belong in the available minutes?
- Everyone whose work is included in the SMV. If the operation bulletin includes helper operations (trimming, bundling), count those helpers; if it does not, leave them out. Mixing the two definitions is the most common reason two factories report very different efficiencies for the same performance.
- Should rejected or reworked pieces count as output?
- Count only good pieces that passed end-line inspection. Counting rework twice, or counting pieces that will be rejected, inflates earned minutes and hides a quality problem as a productivity gain.
- What is on-standard efficiency?
- Efficiency calculated after removing off-standard time the operators could not control - machine breakdown, waiting for cut panels, meetings. It shows how well the line worked while it had work. Report both figures: overall efficiency is what costing depends on.
- Can efficiency be above 100%?
- Yes, arithmetically. It means the line produced more standard minutes than the minutes it was present. In practice a sustained figure above 100% usually means a loose SMV, a miscount of operators, or output that includes rework - check those before treating it as real.
- How do you calculate sewing line efficiency?
- Multiply good garments produced by the garment SMV to get earned minutes, divide by total available minutes (operators multiplied by working minutes), and multiply by 100. For 600 garments of SMV 12 made by 30 operators in 480 minutes, efficiency is 7,200 ÷ 14,400 × 100 = 50.0%.
- Why does overtime lower line efficiency if output does not rise in proportion?
- Every overtime hour adds 60 available minutes per operator to the denominator. If fatigue slows the pace during the extra hours, earned minutes grow more slowly than available minutes and overall shift efficiency drops.
- What is the difference between line efficiency and operator efficiency?
- Operator efficiency measures one person on one operation against that operation SMV. Line efficiency measures the whole line against the complete garment SMV; waiting between unbalanced workstations lowers line efficiency even when individual operators work briskly.
Read the full guide
Sources & verification
Earned (standard) minutes and their ratio to time worked are the basic productivity measures of work measurement described in the ILO's Introduction to Work Study (Kanawaty, ed., 4th ed., 1992). The worked example above is recomputed in the site's automated tests.