On a 2.9% + 30¢ rate, the fixed fee costs you more than the percentage on any transaction below $10.34. The crossover is exact: divide the fixed fee by the rate. $0.30 ÷ 0.029 = $10.34.
The arithmetic
crossover = fixed fee / percentage rate
2.9% + 30¢ -> 0.30 / 0.029 = $10.34
2.9% + 49¢ -> 0.49 / 0.029 = $16.90
2.6% + 25¢ -> 0.25 / 0.026 = $9.62
3.5% + 10¢ -> 0.10 / 0.035 = $2.86That last line is worth a second look. A rate advertised as 3.5% has a fixed-fee crossover of under $3 — so on almost any realistic transaction the percentage dominates. The headline looks worse and behaves better on small tickets.
What it does to the effective rate
| Transaction | Fee | Effective rate | Fixed fee as a share |
|---|---|---|---|
| $5 | $0.45 | 8.90% | 6.00% |
| $10 | $0.59 | 5.90% | 3.00% |
| $25 | $1.03 | 4.10% | 1.20% |
| $50 | $1.75 | 3.50% | 0.60% |
| $100 | $3.20 | 3.20% | 0.30% |
| $250 | $7.55 | 3.02% | 0.12% |
Same rate card, and the real cost varies by nearly three times. A coffee shop and a furniture retailer on identical published pricing are not paying anything like the same.
Why micro-transactions barely work
This is the structural reason a 50¢ purchase is not a viable product. At 2.9% + 30¢, processing a 50¢ payment costs 31.5¢ — 63% of the sale — before you have paid for anything else.
Every workable model for very small payments works around the fixed fee rather than absorbing it: prepaid credits, wallet top-ups, batching a month of usage into one charge, or bundling into a subscription.
What to do about it
- Find your real average ticket — total volume ÷ transaction count from a statement, not your list price.
- Compare providers at that number, not on headline rates. The fee impact calculator does it directly.
- Batch where you can. One $60 charge instead of six $10 charges pays the fixed fee once and saves $1.50 — 2.5% of the revenue.
- Consider annual billing. Twelve monthly charges of $49 cost about $20.65 in fees; one annual charge of $490 costs about $14.51.
Sources
- Arithmetic derived from published standard rates, September 2026. Every figure above is reproducible from the rate cards in our processor fee comparison.
GOOD QUESTIONS
Frequently asked
At what transaction size does the fixed fee overtake the percentage?+
On a 2.9% + 30¢ rate, at $10.34. Below that the flat 30¢ is the larger of the two components; above it the percentage takes over. The crossover is simply the fixed fee divided by the rate: 0.30 ÷ 0.029.
Why does the fixed fee matter so much on small transactions?+
Because it does not scale. The percentage takes the same share of every sale, but 30¢ is 30¢ whether the sale is $5 or $500 — so proportionally it costs a hundred times more on the small one.
Should low-ticket businesses choose a processor differently?+
Yes. Compare fixed fees before percentages. A provider at 3.1% + 15¢ beats one at 2.9% + 30¢ on every transaction below about $75, despite advertising a higher rate.
How do I reduce the impact of fixed fees?+
Increase the average transaction — bundle, batch or move to annual billing. Charging one $60 invoice instead of six $10 ones pays the fixed fee once instead of six times, saving $1.50 on $60 of revenue.