SMV & SAH Capacity Calculator (Standard Hours to Pieces)
Calculate how many garment pieces a factory can produce given available Standard Allowed Hours (SAH) and style SMV.
Use SAH when planning at factory level: one number covers every line, every shift, and every style in the period. For a single line in a single shift, the Line Capacity Calculator gives the same answer in line terms.
What is SMV and SAH Capacity?
SMV, the standard minute value, is the time a trained operator needs to make one garment at standard pace. SAH, standard allowed hours, is the factory side of the same coin: the total labour time available, expressed in standard hours. One SAH equals 60 standard allowed minutes. Converting available labour into SAH lets planners answer the factory-level question: given the people and hours we have, and the efficiency we actually achieve, how many pieces of this style can we produce?
This is the same minutes logic as line capacity, scaled up. A single line of 30 operators on an 8-hour shift holds 240 SAH per day; a floor of 10 such lines holds 2,400 SAH per day, and over 26 working days that is 62,400 SAH per month. Once labour is expressed in SAH, styles with different SMVs can be compared directly, and an order can be checked against total factory capacity instead of line by line.
Formula
Piece Capacity = (Available SAH × 60 × Efficiency % / 100) / Style SMV
- Available SAH: total planned labour hours for the period, for example operators × working hours.
- 60: converts SAH into standard allowed minutes.
- Efficiency %: factory or line efficiency actually achieved, for example 80 for 80%.
- Style SMV: standard minutes needed to make one garment of this style.
The middle step has its own name: produced minutes, also called earned minutes, equal available minutes multiplied by efficiency. This calculator shows produced minutes alongside piece capacity, because produced minutes are what IE teams track week to week.
How to Calculate
- Work out available SAH for the period: planned operators multiplied by planned working hours, excluding unpaid breaks and holidays.
- Multiply SAH by 60 to get total available minutes.
- Multiply available minutes by efficiency as a decimal to get produced minutes.
- Divide produced minutes by the style SMV to get piece capacity for the period.
- Compare piece capacity against the order quantity: if capacity is lower, you need more SAH (more lines, more days, or overtime) or a later shipment date.
Example
A factory plans 1,000 SAH for a style with an SMV of 12.0 minutes, at 80% efficiency. Total available minutes = 1,000 × 60 = 60,000 minutes. Produced minutes = 60,000 × 0.80 = 48,000 minutes. Piece capacity = 48,000 / 12.0 = 4,000 pieces. If efficiency improves to 90%, produced minutes rise to 54,000 and capacity rises to 4,500 pieces, with no extra workers and no extra hours.
The same logic ties back to the single-line tools. One line of 30 operators on an 8-hour shift holds 30 × 8 = 240 SAH. At 75% efficiency, produced minutes = 240 × 60 × 0.75 = 10,800 minutes, and piece capacity = 10,800 / 12.0 = 900 pieces, which is exactly the daily target the Daily Production Target Calculator gives for the same line. One formula, two views: SAH for the factory, operators and hours for the line.
Assumptions
This calculation assumes a single style SMV across the whole SAH block. In a real factory, lines run mixed styles with different SMVs, so the honest approach is to split SAH by style and calculate each style separately, then add the piece counts. It also assumes the efficiency figure is a genuine average for the period, not a best-day figure, and that bottleneck operations do not cap output below the minutes result: check bottleneck operations with the Machine Capacity Calculator before committing to a factory-level number.