TL;DR
Interchange-plus pricing passes the Visa or Mastercard wholesale fee straight through and adds a fixed processor markup on top. At $250K monthly in-person volume, our engine puts Stax at 1.79 percent and Helcim at 1.94 percent, against 2.76 percent on Square and 2.80 percent on Stripe (prices checked Oct 2026). Helcim wins at lower volume and is the cheapest option we price at $10K and $50K a month. Stax overtakes it by $250K. Payment Depot sells interchange-plus by quote only. Worldpay is for large merchants with a negotiated deal. Even under $10K monthly, Helcim's no-monthly-fee interchange-plus costs less than flat rate in our engine ($211 against $290 on Square's Free plan); it is subscription plans that do not pay off at that size.
How we ranked
We scored each processor on six criteria with explicit thresholds:
- Effective rate at $250K monthly volume on a 70/30 card-present and card-not-present mix.
- Contract length and early termination fee. We penalize anything over 12 months without a no-fee out clause.
- Settlement speed counted in business days from batch close to bank deposit.
- Level 2 and Level 3 data support. This matters if more than 15 percent of your volume is B2B or government cards.
- Hardware lock-in. Closed-ecosystem terminals raise your switching cost.
- Public pricing. If the markup is not on the website, we treat that as a yellow flag.
We pulled interchange categories from the Visa Interchange Schedule and Mastercard Interchange Rates and Criteria, both published by the card networks. Processor markups came from each provider's public pricing page, checked Oct 2026. We did not score sales-pitch features like advanced reporting or AI dashboards. Operators pay for the rate, the contract, and the settlement window.
At a glance
Headline pricing from each provider's pricing page, checked Oct 2026. Worldpay and Stripe's interchange-plus pricing are quote-only.
| Provider | Headline pricing | Contract | Settlement | Best for | Watch out for |
|---|---|---|---|---|---|
| Helcim | IC + 0.40% + $0.08 in-person under $50K/mo, stepping down with volume | None | Next business morning | $10K to $50K+ monthly, no monthly fee | Online fixed fee of $0.25 under $50K |
| Stax | $99 to $199+/mo + IC + $0.08 in-person, $0.15 online | Length not published; no cancellation fees stated | Next business day | $250K+ monthly in our engine | Subscription cost under $50K |
| Payment Depot | Interchange-plus by quote; no prices listed | No cancellation fees; $0 setup | Not published | Merchants who get a written quote | Full cost not public |
| Stripe (custom) | IC + custom % (request) | Custom | 2 days | High-volume online businesses that can negotiate | Standard plan is flat 2.9% |
| Worldpay | IC + custom (sales) | Not published | Not published | Large and enterprise merchants | No price list; read the exit terms |
Helcim
Helcim publishes interchange-plus rates on its website, which is rare in this industry. The card-present markup is 0.40 percent plus 8 cents, and online is 0.50 percent plus 25 cents per the published pricing page. Automatic volume discounts kick in at $50K, $100K, $500K, and $1M monthly tiers, down to 0.15 percent plus 6 cents in person. There is no monthly fee, no setup fee, no PCI fee, and no contract.
Our engine assumes a $50 average sale and about 1.55 percent blended interchange and network fees in person, an estimate built from the Visa schedule and the Regulation II debit cap. On that basis Helcim comes to about 2.04 percent ($1,020) at $50K a month and 1.94 percent ($4,850) at $250K, against Square's 2.6 percent plus 15 cents at 2.90 percent ($1,450) and 2.76 percent on Premium ($6,900).
Who it's for: SMB retail, restaurant, and professional services from about $10K to $250K monthly volume that wants pricing transparency without a sales-call negotiation.
Who should avoid it: high-risk verticals (check Helcim's restricted business list before applying), merchants who need a dedicated account manager, and anyone who needs instant payouts, which Helcim does not offer.
Hardware: the Helcim Card Reader is $199 and the Smart Terminal is $349, or $32 a month for a year. Funding is next business morning, free.
Stax
Stax (formerly Fattmerchant) charges a monthly subscription of $99 up to $150K a year in volume, $139 from $150K to $250K and $199 or more above that, then passes interchange straight through with an $0.08 fee on in-person transactions and $0.15 on online transactions per the public pricing page (checked Oct 2026). There is no percentage markup over interchange on the base plan.
The math at $50K monthly volume with a $50 average sale (1,000 transactions): per-transaction fees total $80, plus the $199 subscription that applies at $600K a year. Total markup: $279, or 0.56 percent over interchange. At $250K monthly (5,000 transactions): $400 plus $199 equals $599, or 0.24 percent. In our engine Helcim is still slightly cheaper at $50K ($1,020 against $1,055 in person) and Stax is cheaper by $250K. Below $50K, you are paying for capacity you do not use.
Who it's for: established retail, e-commerce, or B2B merchants with steady volume, roughly $250K a month and up in our engine, that want subscription-style pricing. Ask for the contract length in writing, because the pricing page does not state it.
Who should avoid it: low-volume merchants under $50K monthly. The subscription is dead weight at that tier. Hardware: SwipeSimple reader $125, Dejavoo QD4 countertop $310, QD2 wireless $495. Funding is next business day.
Payment Depot
Payment Depot sells interchange-plus pricing by quote. Its pricing page (archived Oct 2025) lists no monthly or per-transaction price; it says $0 setup and no cancellation fees. Ask for the full fee schedule in writing.
The math needs the quote. At $100K monthly in-person volume with a $50 average sale (2,000 transactions), every cent of per-sale fee adds $20 a month and every 0.10 percent of markup adds $100. Until you have the quote in writing, you cannot compare it with Stax or Helcim, which is why Payment Depot is not in our cost engine.
Who it's for: steady-volume retail, food service, and B2B merchants that want interchange-plus pricing and will get the full quote in writing before signing.
Who should avoid it: businesses with high ticket counts but low average ticket size, if the quote carries a per-transaction fee. It compounds against you when the average ticket is under $20.
Contract: Payment Depot states $0 setup and no cancellation fees. Settlement timing and hardware prices are not published on its pricing page; ask whether your current terminal can be reprogrammed.
Stripe (custom interchange-plus)
Stripe's published plan is flat-rate at 2.9 percent plus 30 cents online and 2.7 percent plus 5 cents in-person. That is not interchange-plus. For larger merchants, Stripe can offer custom pricing, including interchange-plus, by negotiation. It is not on the public page and requires a sales conversation.
At $250K monthly online volume with a $50 average sale, Stripe's flat-rate plan comes to about 3.50 percent ($8,750 a month) in our engine, against 2.45 percent ($6,125) on Helcim's published online interchange-plus. That is $31,500 a year, which sets the bar a negotiated Stripe rate has to beat.
Who it's for: higher-volume online merchants who want Stripe's developer tooling, broad currency support, and global card acquiring, and who are willing to negotiate.
Who should avoid it: cost-sensitive small merchants who are unlikely to get a custom deal, where the flat rate eats the margin. Also avoid for in-person-heavy retail. Stripe Terminal is functional but the surrounding POS ecosystem trails Square and Clover.
Worldpay
Worldpay, now part of Global Payments, does not publish a price list. Every deal is interchange-plus or interchange-plus-plus, negotiated with a sales representative, with markups that depend on volume, vertical, and contract length.
Because nothing is published, we cannot state a typical markup. Get a written quote that lists the markup, every fixed fee, the contract length and the exit terms, and benchmark it against Helcim's and Stax's published prices.
Who it's for: $5M+ monthly enterprise merchants, multi-location retail and hospitality, and complex B2B with level 3 data and large-ticket settlement needs.
Who should avoid it: small merchants who want posted prices without a sales process. Contract length and exit fees are set in each negotiated agreement, so read them before signing. Most small merchants can price Helcim or Stax from their public pages instead.
Hardware options and funding timing are not published; confirm both in the quote.
Verdict
For $10K to $50K monthly volume, and for anyone who wants no monthly fee, Helcim wins. Public pricing, no contract, no monthly fee, and the lowest cost in our engine at $10K ($211 in person) and $50K ($1,020).
As volume climbs, Stax wins on the math: at $250K a month in person it comes to about $4,475 against $4,850 for Helcim, and at $1M to $17,300 against $18,200. Ask for its contract length in writing. Payment Depot needs a written quote before it can be compared.
For high-volume online businesses on Stripe, ask for custom pricing. The flat-rate plan leaves money on the table at that volume per the public pricing page.
For large enterprise merchants, Worldpay or another large acquirer can make sense, but only on a written quote you can benchmark against published prices.
Under $10K monthly, skip subscription models: the fixed monthly cost erases the rate savings. Interchange-plus with no monthly fee still costs less in our engine ($211 a month at $10K on Helcim against $290 on Square's Free plan), though a flat rate is simpler to predict.