Payment Processing Cost Calculator
Per-transaction cost across Stripe, Square, PayPal, etc.
About this calculator
Card processors rarely charge just one fee — this calculator adds up the three components that make up your real monthly bill: a percentage fee applied to total volume (interchange plus the processor's markup, e.g. Stripe/PayPal's 2.9%), a small fixed fee charged per transaction regardless of size (Stripe's $0.30, Square's lower $0.10), and any flat monthly platform or gateway fee some providers charge on top. It then layers on chargeback costs, estimated from your chargeback rate (industry average runs 0.5-1% of transactions) times a flat per-dispute fee processors charge whether you win or lose the dispute.
Everything rolls up into a total monthly cost, which the calculator also expresses as an annualized figure and — more usefully — as an "effective rate," your all-in fees as a percentage of volume. That effective rate is the number worth comparing across processors, because a lower percentage fee can still lose to a competitor once you account for a monthly platform fee or a higher fixed per-transaction charge; the crossover point depends entirely on your average transaction size, since fixed fees matter far more on small transactions and percentage fees dominate on large ones. A common mixup is comparing headline percentage rates directly — a business running many small transactions should weight the fixed per-transaction fee much more heavily than the percentage rate, while a business with large average tickets should do the opposite.
Inputs
Results
Total monthly cost
$1,866.67
Effective rate (%)
3.73%
How to Use This Calculator
- Enter Monthly volume ($), Avg transaction ($), and Percentage fee (%).
- Set Fixed fee per tx ($), Monthly platform fee ($), and Chargeback rate (%).
- Adjust Chargeback fee ($) as needed.
- Review Total monthly cost ($) and Effective rate (%) (%).
- Use Annual cost ($) and Monthly transactions to inform your decision.
How the result changes with Monthly volume ($)
| Monthly volume ($) | Total monthly cost | Effective rate (%) |
|---|---|---|
| 25,000 | $933.33 | 3.73% |
| 37,500 | $1,400.00 | 3.73% |
| 75,000 | $2,800.00 | 3.73% |
| 125,000 | $4,666.67 | 3.73% |
What each input means
- Monthly volume ($)
- Total dollar amount of card transactions processed per month.
- Avg transaction ($)
- Average dollar amount per individual transaction.
- Percentage fee (%)
- Processor's percentage fee per transaction (e.g., 2.9% for Stripe/PayPal, 2.6% for Square).
- Fixed fee per tx ($)
- Fixed dollar amount charged per transaction (e.g., $0.30 for Stripe, $0.10 for Square).
- Monthly platform fee ($)
- Fixed monthly gateway or platform fee (e.g., $0 for Stripe, $79 for Shopify Advanced).
- Chargeback rate (%)
- Percentage of transactions resulting in chargebacks. Industry average is 0.5-1%.
- Chargeback fee ($)
- Fee charged per chargeback dispute (typically $15-25).
What each result means
- Total monthly cost
- All processing fees, platform fees, and chargeback costs combined per month.
- Effective rate (%)
- True all-in cost as a percentage of monthly volume — the number to compare across processors.
- Annual cost
- Projected total processing cost over 12 months.
- Monthly transactions
- Estimated number of transactions based on volume and average transaction size.
- Percentage fees
- Monthly cost from the percentage-based fee component.
- Fixed per-tx fees
- Monthly cost from fixed per-transaction fees.
- Chargeback costs
- Monthly cost from chargeback disputes.
- Cost per transaction
- Average total fee cost per individual transaction.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMonthly volume ($) = 50000, Avg transaction ($) = 45, Percentage fee (%) = 2.9, Fixed fee per tx ($) = 0.3 = 7 input(s) provided
- Calculate Total monthly costTotal monthly cost = processingCost + monthlyPlatformFee + chargebackCost1866.67 = $1,866.67
- Calculate Effective rateEffective rate = monthlyVolume > 03.733 = 3.733%
- Calculate Annual costAnnual cost = totalMonthlyCost * 1222400 = $22,400
- Calculate Monthly transactionsMonthly transactions = monthlyVolume / avgTransactionSize1111 = 1111
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is the effective rate different from the percentage fee I was quoted?
The percentage fee is only one of three cost components this calculator sums — it also adds the fixed per-transaction fee (spread across every transaction, not just large ones) and any flat monthly platform fee, then divides that total by your monthly volume to get the effective rate. A business with a low average transaction size feels the fixed fee much more per dollar of volume, so its effective rate can run noticeably above the quoted percentage even with no chargebacks at all.
Why does average transaction size matter so much when comparing two processors?
The fixed per-transaction fee is charged once per transaction regardless of amount, so it eats a much bigger share of a $10 sale than a $500 one, while the percentage fee scales evenly with transaction size either way. That means a processor with a lower fixed fee but higher percentage can be cheaper for high-ticket businesses and more expensive for high-volume, low-ticket ones — the calculator's effective-rate output is what actually reflects that crossover for your specific average ticket size.
How is the chargeback cost estimated if I don't know my actual dispute rate?
The calculator multiplies your monthly transaction count by the chargeback rate percentage you enter to estimate how many disputes you'll incur, then multiplies that by the flat per-dispute fee your processor charges. The default 0.5% reflects a typical low-risk merchant; card-not-present or higher-risk categories should use a higher rate, since this fee applies whether you ultimately win or lose the chargeback dispute.
Does a $0 monthly platform fee mean that processor is always cheaper?
Not necessarily — the monthly platform fee is just one of three inputs feeding the total monthly cost, and it's usually the smallest relative to volume once a business has meaningful transaction counts. A processor with no monthly fee but a higher percentage rate or fixed per-transaction charge can still produce a higher effective rate than one with a modest monthly fee, which is exactly why comparing the effective-rate output matters more than comparing any single fee line in isolation.
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