Industrial engineering calculator

Line Efficiency Calculator

Calculate sewing line efficiency from good output, garment SMV, manpower and working hours, with earned minutes, available minutes and output per hour.

Method note: Whether helpers, supervisors and overtime minutes are included is a company definition. Keep it consistent.

Inputs

pcs
min
persons

Include every person you count in the line (operators, and helpers if your method includes them).

h

Result

Line efficiency

62.5%

Earned minutes
12,000min
Available minutes
19,200min
Output per hour
125pcs/h

Compare with the planned efficiency for this style and the learning curve stage of the line, not with a generic benchmark.

Working
  1. Earned minutes = 1,000 × 12 = 12,000 min
  2. Available minutes = 40 × 480 = 19,200 min
  3. Efficiency = 12,000 / 19,200 × 100 = 62.5%

Formula

Formula
η=P×SMVM×T×100\eta = \dfrac{P \times \text{SMV}}{M \times T} \times 100

Efficiency % = (output × SMV) / (manpower × working minutes) × 100

SymbolMeaningUnit
PGood outputpcs
SMVGarment standard minute valuemin
MManpowerpersons
TWorking time per personmin

How the calculator works#

Earned minutes = output × SMV. Available minutes = manpower × working minutes. Efficiency = earned / available × 100. The calculator also shows output per hour.

See line efficiency for definitions and reporting pitfalls.

Worked example#

Defaults: 1,000 good pieces, SMV 12.0, 40 people, 8 hours.

  • Earned minutes = 1,000 × 12 = 12,000
  • Available minutes = 40 × 480 = 19,200
  • Efficiency = 12,000 / 19,200 × 100 = 62.5%
  • Output per hour = 125 pieces

Interpreting the result#

Compare with the planned efficiency for the style and day of the learning curve. If efficiency is low, look first at lost time, the bottleneck and rework. See low line efficiency.

Common input mistakes#

  • Entering total garments sewn, including garments waiting for repair, instead of good output.
  • Using the costing SMV instead of the engineering SMV for the method on the floor.
  • Counting operators only for manpower when your targets include helpers, or the other way round.
  • Leaving out overtime hours when overtime output is included in the count.

Assumptions

  • Output counts only good pieces that passed end-of-line checking.
  • Working minutes are the paid or attended minutes your method uses, including or excluding overtime consistently.

Common errors

  • Counting helpers in manpower on some days and not others, which makes efficiency jump.
  • Using a costing SMV instead of the SMV the line is actually working to.
  • Including repaired garments twice in output.

Questions

Should helpers be counted in manpower?

Count them if your factory's efficiency definition includes them, and use the same definition every day and on every line so results can be compared.

Can efficiency be over 100%?

Yes, if the line works faster than the standard pace. Consistently high values often mean the SMV is too generous.

Which output should I enter?

Good garments that passed end-of-line checking in the period, not garments still waiting for repair.

Related formulas

Guides for this calculation

Industrial EngineeringGuide4 min read

Garment Line Efficiency: Formula, Example and Calculator

Line efficiency compares the minutes a sewing line earned with the minutes it had. Learn the formula, work through examples, understand what drives efficiency up and down, and avoid the reporting mistakes that make the number meaningless.

TroubleshootingTroubleshooting3 min read

Low Line Efficiency: How to Find Where the Minutes Go

When a sewing line runs well below its planned efficiency, the cause is usually in a few places: the SMV, the balance, lost time, quality or people. A structured way to check each one and fix the biggest losses first.

Industrial EngineeringHow-to3 min read

Production Target Calculation for Sewing Lines

How to set an hourly and daily production target from SMV, manpower, working minutes and planned efficiency. Worked examples for new and running styles, learning curve targets and why a target at 100% efficiency is not a real target.

Industrial EngineeringGuide4 min read

What Is SMV? Standard Minute Value in Garment Manufacturing

SMV is the standard time to complete a task at a normal pace, including allowances. Learn what it includes, how it is set, how it drives targets, efficiency, capacity and CM cost, and where it goes wrong.

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