Short answer
Every fee line on a merchant statement links three numbers: the rate, the turnover it applies to and the fee charged. If you have any two, you can work out the third. Fee divided by turnover gives the rate, rate times turnover gives the fee, and fee divided by rate gives the turnover.
Part of Reading statements. Start with the main guide: How to read a merchant statement, line by line
Key takeaways
- Rate, turnover and fee are linked: knowing two of them gives you the third.
- Fee ÷ turnover = rate. Rate × turnover = fee. Fee ÷ rate = turnover.
- Work line by line, because each fee line has its own turnover and rate.
- Rounding on statements means a recalculated figure can differ by a few pence, which is normal.
- Where a line has both a percentage and a per-transaction part, separate them before you divide.
A statement that hands you everything you need is rare. More often something is missing. The fee is shown but the rate is not. The rate is shown but the amount it applies to is buried in a summary. The turnover is split across card types and only the total fee is printed.
None of this is a dead end. A fee line is just a multiplication in disguise, and a multiplication can be run in any direction. This guide shows the three calculations you need, applies them to realistic examples, and points out the traps that catch people out, including rounding, tax and fees that combine a percentage with a fixed amount.
What is the relationship behind every fee line?
Almost every percentage-based charge on a statement follows one rule.
Which of the three you can work out depends on which two you have. The table sets out the options.
| You have | You want | Calculation |
|---|---|---|
| Fee and turnover | The rate | Fee ÷ turnover × 100 |
| Rate and turnover | The fee | Rate ÷ 100 × turnover |
| Fee and rate | The turnover | Fee ÷ (rate ÷ 100) |
Keep the percentage as a decimal when you multiply. A rate of 1.5% is 0.015. Mixing up percent and decimal is the most common slip.
How do you work out a missing rate?
You know the fee and the turnover it applies to, but the statement does not print the rate.
Example. A statement shows consumer debit turnover of £6,000.00 and an interchange fee of £12.00 for that turnover. The rate is 12.00 ÷ 6,000 = 0.002, so 0.20%.
That is the regulated cap on consumer debit cards in the UK and Europe, which tells you the figure is plausible. Checking the recovered rate against a published figure is a good sanity test. If the recovered rate looks very different from what you expected, ask why.
Each rate is the printed fee divided by the printed turnover for that line.
The same calculation reveals which fee belongs to the provider. The first two lines are interchange fees, set by the card schemes and regulators. In this example the interchange and scheme fees are pass-through costs, and the 0.40% markup is the provider's own margin. A statement that only shows the total would hide all of this.
How do you work out a missing fee?
You know the rate and the turnover, but the amount charged is missing or unclear.
Example. A contract says 1.4% on standard cards. Turnover on standard cards is £8,500.00. The fee should be 0.014 × 8,500 = £119.00. If the statement charges £127.50, the difference of £8.50 is worth a question. It might be a mix of cards charged at a higher rate, or it might be an error.
This direction is how you audit a statement. Take each rate in the contract, multiply it by the turnover it covers, and compare the answer with what was charged. A mismatch is not proof of a mistake, but it is a reason to ask.
How do you work out a missing turnover?
You know the fee and the rate, but the statement does not say how much turnover the fee applies to.
Example. A fee line shows £18.00 charged at 0.30%. The turnover is 18.00 ÷ 0.003 = £6,000.00.
This is useful when a statement shows a single card turnover figure but you need the split. Run the calculation on each fee line to rebuild the breakdown. Add up the results and check they match the total turnover. If they do not, a line is wrong or another fee type is involved.
What if a fee has two parts?
Many fee lines combine a percentage and a fixed amount per transaction, for example 1.2% + 5p. The simple formulas do not work until you split the two parts.
You need the number of transactions. Then:
- Work out the fixed part: per-transaction fee × number of transactions.
- Subtract it from the total fee.
- Divide what is left by the turnover to get the percentage part.
Example. A line shows a total fee of £174.00 on turnover of £12,000.00 across 600 transactions. If the contract says the fixed part is 5p per transaction, the fixed part is 600 × 0.05 = £30.00. The percentage part is £174.00 − £30.00 = £144.00, and 144 ÷ 12,000 = 0.012, so the percentage is 1.2%.
If the statement does not show the transaction count, you cannot separate the parts, and any rate you calculate will be a blend. That is a gap in the statement, not in your maths. Ask for the count.
How do you chase a total back to its parts?
Sometimes the statement gives only totals: total turnover and total fees. You can still learn something. The effective rate is total fees ÷ total turnover. For finer detail, you need the line items, and you may have to ask for them.
A reliable order of work is:
- List every number printedTurnover, transaction count, each fee and each rate.
- Sort the fees into linesPercentage-based, per-transaction, fixed monthly.
- Fill in each gapUse the three-way link on one line at a time.
- Add the rebuilt lines upThey must equal the total fee on the statement.
- Flag what does not add upDifferences are your questions for the provider.
Start with what is printed and rebuild what is not.
Which traps catch people out?
Rounding
Statements round to the nearest penny or cent. A recalculated fee can differ from the printed one by a few pence without anything being wrong. A difference of a few pence is rounding. A difference of several pounds is not.
Tax
Some fees are shown with tax, others without. If a rate multiplied by turnover does not match the fee, check whether tax has been added. A fee of £150.00 plus 20% tax is £180.00. If the printed fee is £180.00 and you divide it by turnover, the rate you get is 20% too high.
Gross versus net turnover
A fee may apply to gross turnover (before refunds) or net turnover (after refunds). If your recovered rate is slightly off, try the other basis. See refunds, chargebacks and turnover for how refunds change the picture.
Mixed cards on one line
A line labelled "standard cards" might cover several card types with different rates. If the recovered rate does not match any single rate in the contract, it is probably an average. Ask for a breakdown by card type.
Currency conversion
For payments in another currency, the fee may be shown in the original currency and the turnover in your own. Make sure both figures are in the same currency before you divide.
A full worked example
A merchant statement shows:
| Printed | Value |
|---|---|
| Total card turnover | £10,000.00 |
| Transactions | 500 |
| Interchange fees | £70.00 |
| Scheme fees | £17.00 |
| Provider fee (rate not shown) | £60.00 |
| Terminal rental | £20.00 |
From this, you can recover several things.
- Interchange rate: 70 ÷ 10,000 = 0.70%.
- Scheme rate: 17 ÷ 10,000 = 0.17%.
- Provider fee rate: 60 ÷ 10,000 = 0.60%. If the provider says it charges 0.5% plus 2p per transaction, check: 0.5% × 10,000 = £50.00 plus 500 × 0.02 = £10.00, total £60.00. It matches.
- Total fees: 70 + 17 + 60 + 20 = £167.00.
- Effective rate: 167 ÷ 10,000 = 1.67%.
Without a single rate printed on the statement, you now have the full cost structure. The checkmyrates calculator includes tools for each of these cases: you enter the two figures you have and it works out the third, line by line.
Why does this matter for consultants?
Prospects hand over incomplete statements all the time. The ability to rebuild the missing figures means you do not have to stop and ask for a better copy, and it lets you show a merchant a cost structure they have never seen. It also guards against misleading statements. A provider whose lines do not reconcile gives you something to raise. Our guide to analysing a statement in five minutes shows how this fits into a full review.
Frequently asked questions
How do I calculate my merchant rate from a statement?
Divide the fee for a line by the turnover it applies to, then multiply by 100. For a fee of £12.00 on £6,000.00 of turnover, the rate is 0.20%.
How do I find turnover if the statement does not show it?
Divide the fee by the rate as a decimal. A £18.00 fee charged at 0.30% means turnover of 18 ÷ 0.003, which is £6,000.00.
Why does my calculated fee differ slightly from the printed fee?
Usually rounding. Statements round to the penny or cent. If the difference is more than a few pence, check for tax, mixed card types or per-transaction fees.
What if a fee has both a percentage and a per-transaction part?
Work out the per-transaction part first by multiplying the fee per transaction by the number of transactions. Subtract it from the total fee, then divide what remains by the turnover.
Can I recover the effective rate from totals alone?
Yes. Divide total fees by total turnover. You cannot split the fee into its causes without the line items.
Is it worth checking every line?
For a first review, yes. Once you know a provider's pattern, a quick check of the biggest lines is usually enough. Always check again if the total changes sharply.
Sources and further reading
Figures in this guide are examples to show the method. Fees, rules and rates change, so check your own statement, contract and current rules before you decide. This is general information, not financial or legal advice.