Capacity is the amount of work a factory or line can produce in a period. In garment manufacturing, the most reliable way to express it is in standard minutes, because a line that makes 1,200 T-shirts a day may make only 400 jackets. Minutes let you compare different styles on the same scale.
Capacity in minutes#
Not all available minutes become output. Adjust for absenteeism and efficiency:
Capacity in pieces#
Divide standard minutes by the SMV of the style:
Worked example: one month#
A factory has 10 sewing lines with 35 operators each. It works 26 days in the month, 8 hours (480 minutes) a day. Average absenteeism is 5% and average efficiency is 58%.
- Operators: 10 × 35 = 350
- Available minutes: 350 × 480 × 26 = 4,368,000
- After absenteeism: 4,368,000 × 0.95 = 4,149,600
- Capacity in standard minutes: 4,149,600 × 0.58 = 2,406,768
For a T-shirt with SMV 10.5: 2,406,768 / 10.5 = 229,216 pieces in the month.
For a jacket with SMV 45: 2,406,768 / 45 = 53,483 pieces.
Does the order fit?#
Convert the order into minutes and compare with capacity:
| Order | Quantity | SMV | Minutes required |
|---|---|---|---|
| Basic T-shirt | 80,000 | 10.5 | 840,000 |
| Polo shirt | 40,000 | 16.0 | 640,000 |
| Hoodie | 20,000 | 28.0 | 560,000 |
| Total | 2,040,000 |
Required: 2,040,000 minutes. Capacity: 2,406,768 minutes. The load is about 85% of capacity. There is room for about 366,000 more standard minutes, but not every line may be suited to every style. Check line by line as well as in total.
Things that reduce real capacity#
- Style changes: the first days of a new style run at lower efficiency. Many small orders mean more changeovers.
- Machine availability: a style may need special machines (kansai, bartack, snap attach) that only a few lines have.
- Skills: a line experienced in T-shirts may struggle with woven shirts.
- Material delays: late fabric or trims leave lines idle even when capacity exists.
- Holidays and overtime: adjust working days and minutes for the actual calendar.
Line-level capacity#
Planning by line is more accurate than planning by factory total:
| Line | Operators | Efficiency (recent) | Daily capacity (std min) |
|---|---|---|---|
| L1 | 36 | 62% | 36 × 480 × 0.62 = 10,714 |
| L2 | 32 | 55% | 32 × 480 × 0.55 = 8,448 |
| L3 | 40 | 60% | 40 × 480 × 0.60 = 11,520 |
Use each line's recent actual efficiency for the style family, not a factory average.
Common mistakes#
- Planning in pieces across styles with different SMVs.
- Using target efficiency instead of achieved efficiency, which makes capacity look bigger than it is.
- Forgetting absenteeism and leave.
- Ignoring non-sewing capacity: cutting, printing, embroidery, washing and finishing can be the real limit. See bottleneck analysis.
Use the capacity calculator to run these numbers, and the capacity study template to plan line by line. For how capacity feeds into a production plan, see production planning basics.
Related guides#
- Production target calculation: turning capacity into daily and hourly targets.
- Line efficiency: the efficiency figure that capacity depends on.
- What is SMV: the standard minutes capacity is measured in.
- Process flow chart and layout of garments finishing: checking finishing capacity as well as sewing.
Frequently asked questions#
Should capacity include overtime? Plan base capacity on normal hours. Treat overtime as a flexible reserve for recovery, not as part of the standard plan, and follow legal and buyer limits on working hours.
How often should capacity be recalculated? Update it at least monthly with actual efficiency, manpower and working days, and whenever lines are added or removed.