Tray requirements are usually estimated by guesswork, which is why salons alternate between running out mid-week and holding stock nobody uses. The number can be calculated from service volume and D count, and once it is calculated the reorder interval stops being a judgement call.
Start from fans per set, not trays per month
Fans per full set depends primarily on the D count, because a denser fan covers more lash line per placement. Approximate ranges used in practice:
- 4D: roughly 120 to 160 fans per full set
- 5D: roughly 130 to 180 fans
- 7D: roughly 140 to 200 fans
- 8D: roughly 150 to 210 fans
- 9D: roughly 150 to 200 fans
- 10D: roughly 130 to 180 fans
- 12D: roughly 100 to 150 fans
The range is wide because coverage is not the only variable. Client lash density, the length of the set, infill versus full set, and artist technique all move the number. Treat these as starting estimates to be replaced by your own measured average after a month of tracking.
Convert to trays using actual count per tray
Fans per tray is not a standard number and should be confirmed per SKU. Dividing fans per set by fans per tray gives trays per set — usually a fraction, which is the useful figure. A set that consumes 180 fans against a 1,000-fan tray uses 0.18 of a tray. Ten such sets per week consume 1.8 trays.
Working in fractions rather than rounding up per set avoids the common error of overestimating. Rounding every set up to a whole tray grossly inflates requirement when a tray covers several sets.
Account for infills separately
An infill consumes far fewer fans than a full set — typically a third to a half, depending on retention and the interval. If a salon does mostly infills with occasional full sets, average consumption per appointment is lower than fans-per-full-set suggests, and stock planning based only on full sets will over-order.
A workable approach is to track average fans per appointment across a month, mixing full sets and infills, then use that single number for planning rather than modelling each service type separately.
Watch consumption for signals
Average fans per appointment is also a diagnostic number. If it rises without a change in service menu, one of three things usually happened: the tray was filled with fewer fans than before, artists are using more fans to achieve the same look (often a base or opening issue), or the client mix shifted toward denser sets. Checking tray count before assuming waste is the faster path.
Set a reorder point, not a reorder date
Because appointment volume varies, a fixed reorder date is always wrong. A reorder point in trays works better: when stock for a given SKU falls below the amount consumed in the supplier’s lead time plus a buffer, order. That number is derived from your own consumption rate, so it adapts automatically when the salon gets busier.
One detail worth confirming before setting reorder points: how many fans the tray actually contains. Fill quantity is a quiet variable, and a change of ten percent per tray moves every downstream calculation.