The short answer
A billing-floor minimum sets the least you will pay for a defined group of eligible charges in a period. If those fees are below the floor, you pay a shortfall. Excluded charges are added separately. Confirm this is a billing floor, rather than a separate account fee or a volume commitment.
Which fees count?
There is no universal eligibility list. A contract may include pick/pack, returns or other handling charges and exclude storage, postage or technology—or define a different grouping. Ask for explicit inclusions, exclusions and an example invoice.
The Fulfillment Cost Calculator counts first-item fees, additional-item fees and returns toward the minimum. It adds storage, other recurring fees and shipping outside the floor. This is the tool's calculation rule, not a claim about every 3PL contract.
Use the Fulfillment Cost Calculator when that eligibility matches your proposal.
Example: a low-volume month
Assume 200 orders, 1.5 items per order, $2 first-item and $0.50 additional-item fees. Pick/pack is $450. Add $50 returns, eligible in this example: $500 against a $750 minimum. The shortfall is $250.
Add $150 storage outside the minimum: total $900, or $4.5 per order before postage. You are not paying $750 plus all $500 eligible fees; the eligible portion is topped up to $750.
Why minimums matter more at low volume
When the same $750 floor applies to only 100 orders, that floor alone is $7.50 per order, before excluded charges. At higher volume, eligible fees may exceed the floor and no shortfall applies. Model the slow month—not only your optimistic sales forecast.
A minimum is not necessarily unreasonable: it may support reserved capacity or account work. The commercial question is whether the cost and commitment fit your current business.
Ask about a startup ramp
Ask when the floor starts, whether onboarding or partial months are prorated, and whether a temporary ramp or seasonal arrangement is available. Confirm whether minimums apply per account, warehouse or service, and whether they change with renewal or price increases.
Get any ramp, waiver or negotiated concession in writing. This is a commercial interpretation, not legal advice; do not assume an informal sales discussion changes the signed terms.
Compare the full proposal using How to compare 3PL quotes.