What gross-up means
Gross-up is the process of increasing a charge so that, after a known deduction, the remaining net amount reaches a specific target. It is useful for payment processing, platform commissions and other simple fee structures that can be represented by a percentage plus a fixed amount.
The calculation is purely mathematical. Whether you are allowed or commercially willing to pass that cost to a client is a separate contractual and legal question.
The formula
If the fee is 3.4% + €0.35 and you want to receive €1,000:
Because real payments use currency precision, the result must then be checked at the cent level. The Earnquo gross-up calculator searches for the smallest cent amount that still leaves at least the target net.
Worked examples using 3.4% + €0.35
| Desired net | Minimum charge | Estimated fee | Resulting net |
|---|---|---|---|
| €100.00 | €103.88 | €3.88 | €100.00 |
| €500.00 | €517.96 | €17.96 | €500.00 |
| €1,000.00 | €1,035.56 | €35.56 | €1,000.00 |
| €2,500.00 | €2,588.35 | €88.35 | €2,500.00 |
As the transaction grows, the fixed fee becomes less important relative to the percentage component. The gross-up still matters because the percentage is always applied to the final gross amount.
Why adding 3.4% directly is not the same thing
A common shortcut for a €1,000 target is €1,000 × 1.034 + €0.35 = €1,034.35. But if 3.4% + €0.35 is then deducted from that final charge, the resulting net is only €998.83. The fee is also charged on the extra amount you added.
The shortfall may look small on one payment. Repeating the shortcut across many transactions turns it into systematic under-recovery.
Rounding is part of the problem, not a cosmetic detail
The algebra can produce fractions of a cent. Payment systems settle in currency precision, so the practical question is not merely the unrounded formula result. You need the smallest payable amount that still produces a net at or above the target after fee rounding.
Earnquo calculates the fee at cent precision, then checks one-cent steps around the formula result. This avoids reporting a gross amount that looks mathematically correct but leaves the target one cent short.
When the simple formula is appropriate
The generic gross-up calculator works well when the entire deduction can be represented by one percentage fee and one fixed fee.
- Standard card or wallet processing represented by percentage + fixed fee.
- A marketplace or platform commission with a flat percentage and optional fixed amount.
- A simple internal pricing model where you explicitly know the deduction structure.
When it is not enough
- Tiered rates that change after a volume threshold.
- Currency conversion spreads or exchange-rate margins.
- Multiple sequential deductions that are calculated on different bases.
- Tax withholding, VAT or sales tax that follows separate legal rules.
- Minimum, maximum or capped fee structures.
Gross-up and invoice pricing are not automatically the same policy
The calculation can tell you the amount required to preserve a target net. It cannot decide whether the extra cost belongs on the invoice, inside your base price or on your own expense line. Some providers, contracts or jurisdictions may restrict surcharging or require specific disclosures.
For the commercial side of that decision, read how to account for payment fees in client pricing.
A practical workflow
- Identify the exact fee that applies to the transaction.
- Decide the net amount the business actually needs to keep.
- Use the reverse formula or calculator to find the gross amount.
- Check whether separate conversion, tax or cross-border costs also apply.
- Decide how the fee is presented commercially and document that policy.