The client changes an event from 180 guests to 220. The count moved once. In a manual system, the recipe sheet, shopping list, prep plan, pack list, quote, and purchase orders can all disagree in different ways.

The first step is not multiplying every number by 220 ÷ 180. It is deciding which kind of number you are looking at.

Quantities that usually scale

Food portions tied directly to the guest count use a scale factor:

Scale factor = new guests ÷ original guests
220 ÷ 180 ≈ 1.2222

A recipe quantity planned at 18 lb for 180 guests becomes:

18 lb × 1.2222 ≈ 22 lb

Keep the recipe’s own batch and yield rules intact. If the kitchen cooks only full batches or whole pots, translate the scaled need into the production quantity the crew can actually make.

Buying rounds differently

A recipe can need 22 lb while the supplier sells 10 lb packs. The buy becomes three packs, not 2.2. Check whether the extra product has a planned use and whether any trusted on-hand quantity should reduce the purchase.

Do not subtract an inventory number merely because it exists. A physical count needs a date, and movements after that date have to be understood before the number is safe to use.

Fixed quantities may stay fixed

Not everything follows the guest count:

  • The number of delivery vehicles may stay the same or cross a capacity threshold.
  • A serving station, induction unit, or coffee urn may be fixed per station.
  • A venue requirement may apply once to the event.
  • A minimum batch may not shrink or grow linearly.
  • Labels and containers may scale by pan, tray, or batch rather than by guest.

Equipment templates should preserve these fixed counts until a person decides the event has crossed the point where another unit is needed.

Review the money again

At the same illustrative $68 per guest, revenue changes from $12,240 to $14,960. Theoretical food cost may scale close to the guest count, but whole packs, fixed items, minimum batches, and updated supplier prices can move it differently.

Recheck:

  1. Food cost per guest.
  2. Food-cost percentage against the target.
  3. The selling price or fee structure promised to the customer.
  4. Whether the existing quote is still a draft or already a confirmed commitment.

Reissue one plan

The guest count changed once. Your five spreadsheets changed separately. Bring the revised count back to one event record, review the calculation, then issue the shopping, prep, and pack work from the same approved plan.