SMV Calculator: The Short Answer
A trained observer times a sewing line making a T-shirt and records 9 minutes of work at a standard pace. A rating of 100 per cent means no adjustment, and a 15 per cent allowance for rest and machine needs raises the figure to 10.35 minutes. That is the standard minute value, or SMV. At 100 per cent efficiency an operator would finish 5.8 garments an hour. At an illustrative 65 per cent efficiency it is 3.8, or about 30 in an eight-hour day, and at an illustrative five pence per operator minute the labour cost of one garment is about 80 pence. This SMV calculator does that chain for any inputs.
The inputs in this example are placeholders, not benchmarks. A real SMV depends on the style, the operations, the machines and the people, which is why factories measure it rather than copy it.
Use the SMV Calculator
Enter the observed time to make one garment in minutes, the performance rating of the operator you timed and the allowance percentage. Add the line efficiency you expect, the working hours and a labour and overhead cost per operator minute if you want output and cost. The SMV calculator returns the standard minute value, the basic time and the output per operator, per hour and per day.
SMV calculator
SMV, output and cost per garment
Placeholders only, not factory benchmarks. SMV, rating, allowances and efficiency vary by style, operation and factory; use measured values.
The SMV calculator does not replace a time study. It converts the numbers from one into something you can use to compare styles, test a quote and plan capacity. A trained industrial engineer should do the timing and decide the rating and allowances.
What SMV Means
SMV is the time a trained operator, working at a standard pace, needs to complete a task, including allowances for rest and personal needs. For a garment it is the sum of the SMVs of all its operations. A factory uses it to compare styles, to plan how many operators a line needs, to measure efficiency and to build its cut-and-make price.
From a stopwatch to an SMV
- 1Break the garment into operationsJoin shoulders, set sleeves, hem and so on.
- 2Time each operationObserve several cycles and average them.
- 3Apply a performance ratingAdjust to what a standard pace would take.
- 4Add allowancesFor rest, personal needs and machine delays.
- 5Sum the operationsThe total is the garment's SMV.
Work measurement is a branch of industrial engineering, and bodies such as the Institute of Industrial and Systems Engineers and the International Labour Organization provide further reading for those who want to learn the method. Buyers do not need to run time studies, but understanding SMV helps them follow a factory's costing.
An Example Time Study for a T-Shirt
The table lists eight operations for a plain T-shirt with illustrative observed times. They are not benchmarks for any factory, only a worked example of how the total is built. The observed times add up to nine minutes.
Illustrative observed times for a T-shirt
| Operation | Observed seconds | Observed minutes |
|---|---|---|
| Join shoulders | 30 | 0.50 |
| Attach neck rib | 75 | 1.25 |
| Set sleeves | 90 | 1.50 |
| Sew side seams | 80 | 1.33 |
| Hem sleeves | 60 | 1.00 |
| Hem body | 60 | 1.00 |
| Attach label | 25 | 0.42 |
| Trim and check | 120 | 2.00 |
| Total observed | 540 | 9.00 |
Illustrative times to show the method, not benchmarks. Real times depend on the machines, the operators and the style.
Observed seconds by operation in the example
Seconds
Illustrative times from the table above, not benchmarks.
Trimming and checking is the longest operation in this example, which is a reminder that finishing time counts as much as sewing time. A tech pack that is clear about trims and finishing helps a factory time them accurately, as our guide to the tech pack for clothing brands explains.
What the Allowance Adds
Allowances are added to the basic time to account for the fact that no operator can work at standard pace without pause. The size depends on the work, the conditions and the factory's policy. The pie shows the split in the example, and the table shows how the SMV and the output change with the allowance.
Share of the 10.35-minute SMV that is basic time and allowance
- Basic time (9.00 min)87%
- Allowances (1.35 min)13%
Arithmetic: 9.00 ÷ 10.35 = 87.0 per cent basic time; 1.35 ÷ 10.35 = 13.0 per cent allowance. Illustrative 15% allowance.
SMV and output at different allowances (rating 100%, 9 minutes observed)
| Allowance | SMV (minutes) | Garments per operator hour at 100% |
|---|---|---|
| 10% | 9.90 | 6.06 |
| 15% | 10.35 | 5.80 |
| 20% | 10.80 | 5.56 |
Arithmetic: 9 × (1 + allowance), and 60 ÷ SMV. Illustrative allowances, not recommendations.
A five-point change in allowance moves the SMV by about 0.45 minutes, which is a visible change in cost across a large order. When a quote and your own estimate differ, ask what allowance each assumes.
Efficiency: From SMV to Real Output
SMV describes the work, and efficiency describes how much of the available time turns into SMV. A line at 65 per cent efficiency earns 65 minutes of SMV for every hundred minutes it is paid. The table shows output per operator and the labour cost per garment at five efficiency levels for the example SMV.
Output and make cost at different efficiencies (SMV 10.35, 8 hours, £0.05 per operator minute)
| Line efficiency | Garments per operator per day | Make cost per garment |
|---|---|---|
| 50% | 23.2 | £1.03 |
| 60% | 27.8 | £0.86 |
| 65% | 30.1 | £0.80 |
| 75% | 34.8 | £0.69 |
| 85% | 39.4 | £0.61 |
Arithmetic: 480 × efficiency ÷ 10.35, and 10.35 × £0.05 ÷ efficiency. Placeholders for illustration, not factory benchmarks.
Efficiency drives cost as much as SMV does. A move from 50 to 85 per cent cuts the make cost in the example by about 40 per cent. That is why factories invest in training, line balancing and layout, and why a style that is new to a line starts at lower efficiency and improves as operators learn it.
How SMV Feeds the Price You Are Quoted
A factory's cut-and-make charge is built partly on SMV: the minutes the garment needs, multiplied by what a minute of line time costs, adjusted for efficiency. A style with a higher SMV, such as a hoodie with a hood, pocket and rib, costs more to make than a simple T-shirt, for exactly this reason. Our guide to the cost of making a T-shirt shows where the charge sits in the whole cost.
You do not have to ask for the SMV, but asking helps. A factory that quotes a cut-and-make price can usually tell you the SMV it has assumed, and comparing two factories on SMV is fairer than comparing them on price alone. The garment costing calculator shows how the make charge combines with fabric and trims.
SMV and the Choices You Make as a Designer
Design decisions show up directly in SMV. Every extra seam, pocket, topstitch or trim adds operations, and every operation adds seconds. A flat-felled seam takes longer than an overlock, a set-in sleeve longer than a drop shoulder and a lined hood longer than a single-layer one. None of these is wrong, but each has a price, and an SMV calculator lets you see it as minutes before it is a charge on a quote.
A useful exercise is to cost two versions of a style, with and without a detail, by asking the factory for the SMV of each. If a detail adds half a minute of SMV at a cost per minute of five pence, that is a few pence a garment, and on a large order it adds up. If the detail is what makes the garment, it may be well worth it. The point is to decide with the number in front of you.
Where SMV Fits in a Quote Conversation
Most brands never see an SMV, and many do not need to. But a buyer who understands the idea can have a better conversation about price. If a factory says a style costs more to make than expected, the SMV is the explanation: more operations, more minutes. If it says it can make a style cheaper, ask whether that means a lower SMV, a higher assumed efficiency or a lower cost per minute, because each has a different meaning for quality and for risk.
Use the SMV calculator as a way to ask better questions, not as a way to second-guess a factory's engineers. The aim is a shared picture of what the number represents, so that a change in design, quantity or schedule can be discussed in minutes and pence rather than in general terms.
Questions to Ask About SMV
A factory's SMV is only as reliable as the study behind it. A short checklist helps you ask.
Questions to ask about a quoted SMV
- Was it timed on this style, or copied from a similar one?
- What performance rating and allowance were applied?
- Which operations make up the total, and which take longest?
- What efficiency does the quote assume for this line?
- How does efficiency change from a first order to a repeat?
- Does the SMV include finishing, trimming and packing?
A general checklist. Your supplier confirms how its SMVs are built.
Once you know the SMV, the garment production capacity calculator turns it into days of production for an order, and the production lead time calculator places those days on a calendar.
How Ruhrose Helps You Understand Sewing Cost
Ruhrose develops hoodies, fleece, jersey, denim and woven casualwear for UK buyers, with production in Bangladesh. We explain what drives the cut-and-make part of a quote, sample before bulk and help you see how style choices change the sewing time. See our guide to the garment production process and Ruhrose's clothing manufacturing pages for more.
Before you accept a cut-and-make price, ask yourself one question: how many minutes of sewing is it buying?