What Is SMV/SAM and How Is It Calculated?

The single number that quietly drives targets, staffing, and costing on every production line.

An industrial engineer timing a sewing operation with a stopwatch

Reference illustration — will be replaced with a real photo.

The Number Behind Almost Every Production Decision

SMV (Standard Minute Value) — also called SAM (Standard Allowed Minute) at many factories, often used interchangeably — is the time a trained worker should take to complete one operation, working at a steady, sustainable pace with the correct method. It isn't the same as simply timing one worker once; it's a standardised figure meant to be fair, repeatable, and comparable across workers, lines, and even factories.

How SMV Is Actually Calculated

Basic Time = Observed Time × Performance Rating
SMV (or SAM) = Basic Time + (Basic Time × Allowance %)

The observed time comes from timing the operation, usually averaged across several consecutive cycles. The performance rating adjusts for the fact that the specific worker observed might be faster or slower than a "standard" pace — a rating above 100% means they worked faster than standard. Finally, an allowance (commonly covering personal needs, fatigue, and unavoidable machine delays) is added, because no worker can sustain 100% continuous output all day.

A simplified worked example: an operation observed at 0.30 minutes, rated at 95%, with a 20% allowance: Basic Time = 0.30 × 0.95 = 0.285. SMV = 0.285 + (0.285 × 0.20) = 0.342 minutes.

Two Ways SMV Gets Measured

Time Study (Stopwatch Method)

An industrial engineer times a skilled operator performing the actual operation, across several cycles, then averages the readings and applies rating and allowances.

PMTS / GSD (Software Method)

Predetermined Motion Time Systems break an operation into basic hand/body motions, each with a pre-established time value, and calculate SMV without needing to time a live operator.

Why SMV Matters So Much

It's the core input for the Operation Bulletin's machine and manpower calculations.
It sets realistic hourly and daily production targets for a line.
It's used for costing and quoting labour time to buyers.
In piece-rate factories, it's often the basis for calculating worker pay.

Because so much depends on it, an SMV that's copied from an old style without re-checking the actual method or fabric is a common, quiet cause of unrealistic targets and line imbalance.

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