Monthly volume and average order value
Monthly volume is the total amount processed through cards in a typical month, before refunds, in your settlement currency. Average order value is the mean transaction size. Together they determine the transactions count, which the tool derives automatically if you leave the dedicated field blank.
Use a real recent month, not your best month. Seasonal spikes will exaggerate the savings opportunity. If your business is highly seasonal, run the comparison twice — once at peak volume and once at a typical month — and trust the typical-month result.
International percentage
International percentage is the share of your transactions where the buyer's card is issued outside your home market. It is the input that moves the result the most after volume and AOV.
If you do not know the exact share, look at a recent payout statement. Most gateway dashboards break out card origin. A rough estimate is fine — even within plus or minus 10 points, the ranking between providers usually does not change.
Refund rate and chargeback rate
Refund rate is the percentage of transactions you refund in a typical month. Chargeback rate is the percentage of transactions that result in a card-network dispute. These two are different — see the chargeback explainer for why.
Most small businesses have a refund rate between 0.5 and 5 percent and a chargeback rate under 0.5 percent. If you do not know your numbers, start with 2 percent refund and 0.3 percent chargeback as defaults and adjust if you have data.
Sales model and channel
Sales model (B2B or B2C) and channel (Online, Offline, Mixed) do not change the maths but do change which provider gets a structural fit warning. SumUp gets flagged as weaker for online-only businesses; Wise Business is flagged as wrong for card-present B2C even if the cost looks low.
Always pick the option that matches the majority of your volume rather than your aspirational mix. The tool optimises for your reality, not your roadmap.
How to read the output
The comparison table ranks providers by total monthly cost, with the cheapest tagged as 'Best by cost'. The 'effective rate' column is the most useful single number — it is what you actually pay as a percentage of your volume, after every fee category.
The observation list under the table flags structural issues — high international mix, low AOV, elevated refund or chargeback rate — that change which provider is the best fit. Read it before acting on the cost ranking.