EPOS Now vs Legacy POS Fee Structures in 2026: The Real Cost

Modern flat-rate EPOS fee structures charge a single fixed percentage and transaction fee regardless of card type. Legacy interchange-plus pricing separates the wholesale card network cost from the processor markup. Across our statement data, modern cloud EPOS platforms like Square charge an in-person rate of 2.6% + $0.15 on its Free plan. Lightspeed Payments charges 2.6% + $0.10 across its plans. Traditional legacy interchange-plus providers like Helcim charge a transparent margin of 0.4% + $0.08 over wholesale network costs for card-present transactions.

Flat-rate pricing offers predictable billing but blends low-cost debit transactions and high-cost rewards credit cards into one elevated price. Legacy interchange-plus models pass wholesale network rates directly to the merchant. For example, Visa and Mastercard establish a regulated US debit rate of 0.05% + $0.22. Under an interchange-plus structure, you pay that exact regulated debit rate plus the processor's fixed margin. You skip paying a percentage-based flat rate on every debit swipe.

At $10,000 in monthly processing volume with a $50 average sale across 200 card-present transactions, legacy interchange-plus costs $2,568 per year. Flat-rate competitors cost between $3,120 and $3,480 per year. Our data shows Helcim's interchange-plus card-present structure requires $214 per month ($2,568 per year). This yields an effective rate of 2.14%, assuming a 1.58% average credit interchange rate from network tables plus the 0.4% + $0.08 markup. Comparing Helcim vs Shopify, Shopify Advanced card-present flat rate costs $260 per month ($3,120 per year at a 2.6% effective rate). This creates a spread of $1,152 per year between the cheapest and most expensive options.

Scale processing volume to $25,000 per month with a $50 average sale across 500 transactions, and the financial gap widens to an annual spread of $2,880. At $25,000 per month, Helcim interchange-plus card-present totals $535 per month or $6,420 per year at a 2.14% effective rate. Flat-rate card-present plans cost substantially more at this volume. Reviewing Lightspeed vs Square, Lightspeed card-present costs $700 per month ($8,400 per year at a 2.8% effective rate), and Square Free card-present costs $725 per month ($8,700 per year at a 2.9% effective rate). Shopify Advanced card-present costs $650 per month ($7,800 per year at a 2.6% effective rate). Online flat-rate processing under Shopify Advanced costs $775 per month or $9,300 per year at a 3.1% effective rate.

Because Helcim interchange-plus card-present runs a 2.14% marginal all-in effective rate compared to 2.6% on Shopify Advanced card-present and carries no extra fixed monthly processing fee, interchange-plus beats flat-rate processing at every volume tier under this transaction mix.

Flat-rate processing structures bake processor profit margins into a single fee. This exposes merchants to unannounced margin expansion whenever providers adjust their base pricing. On November 4, 2025, Square increased its Square Payments in-person card rate from 2.6% + $0.10 to 2.6% + $0.15. For a merchant processing 500 in-person transactions per month, this single $0.05 fee increase adds $300 in annual processing costs without any change in wholesale card network interchange rates.

Legacy interchange-plus fee structures keep the processor markup contractually separated from wholesale costs. Under an interchange-plus model, when card networks like Visa or Mastercard alter baseline rates, the processor's fixed markup remains constant—such as Helcim's 0.4% + $0.08 card-present margin. Flat-rate platforms absorb wholesale savings when network rates drop and pass rate increases to merchants through higher per-transaction fees. Achieving rate parity requires stripping out the padding flat-rate processors add to wholesale costs.

Calculating the true cost of an EPOS platform requires adding fixed monthly software subscriptions to variable credit card processing rates. Modern cloud POS providers mandate paid subscription tiers for point-of-sale functionality and processing capabilities. Lightspeed Retail requires a monthly subscription of $109 per month on its Basic plan ($89 per month billed annually) or $179 per month on its Core plan ($149 per month billed annually). Shopify requires $39 per month on its Basic plan ($29 per month billed annually).

Mandatory monthly SaaS fees significantly alter your overall effective processing rate, especially at lower sales volumes. Evaluating base credit card fees in isolation obscures hundreds or thousands of dollars in annual software overhead. Weigh software subscription tiers alongside processing markups to accurately calculate out-of-pocket costs.