Vendor fee vs percentage of sales.

Worked example

You expect $2,400 of sales. Option A is a $150 flat fee, 6.25% of sales. Option B is 10% of sales, $240. A is cheaper by $90. The two cost the same at $150 / 0.10 = $1,500 of sales: below that the percentage costs less, above it the flat fee does. Adding a $50 flat part to option B would lower the crossover to ($150 - $50) / 0.10 = $1,000.

How it works

Option A cost = flat fee. Option B cost = flat part + sales x percentage. Setting them equal gives the crossover sales. If B has a lower flat part than A, B is cheaper below the crossover and A above it; if B has a higher flat part than A, B is never cheaper, so no crossover is shown.

The comparison uses the sales you expect, so the result is only as good as that estimate. Run it with a cautious figure and a good one. It ignores other costs of the event such as travel, labour and stock.

Sources and basis (checked 2026-10-08): Arithmetic on your inputs only. Fees and expected sales are the numbers you enter; no typical fee is assumed.

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FAQ

Is a flat fee or a percentage of sales better for a vendor?

Neither always. A percentage costs less on slow days and more on strong ones. The calculator shows the sales level where they cost the same.

What if the organizer charges both?

Enter the flat part in the option B field along with the percentage. The tool adds the flat part to the percentage of your sales.

Which sales figure should I enter?

Your realistic expectation for the event, ideally from past sales at similar events. Try a low and a high figure to see whether the cheaper option changes.

Does the percentage apply to sales before or after tax?

That depends on the organizer. Ask which total the percentage is applied to, and enter the sales on that basis.