Shift4 and Tyro merchants: how to calculate your real costs after the surcharge ban

You know the surcharge model ends on 1 October. The harder question is: what will you actually pay from that day? Neither Shift4 nor Tyro has published a standard post-October rate card for surcharge-model merchants as at June 2026 [3] — so here is a defensible way to forecast your cost yourself, in four steps, using numbers you already have.

Step 1 — Get your monthly card turnover

This is the anchor for everything. Pull it from your terminal dashboard or last three settlement summaries and average it. Watch for seasonality: if December does twice your July, forecast on a typical month and your peak, because percentage-based costs scale with volume.

Step 2 — Find the surcharge rate your customers currently pay

That rate is the best available proxy for the cost your provider needs to recover from someone. It's on your original agreement, your terminal receipts, or your provider portal. Typical surcharge-model rates run ~1.5–1.65%+ [3].

Quick forecast v1: turnover × surcharge rate. A $40,000/month merchant at 1.5% → $600/month ($7,200/year) absorbed from 1 October. That's your "do nothing" baseline.

Step 3 — Adjust for what a market rate would cost instead

Your provider's replacement offer is one option, not the only one. To bracket a realistic range, apply the current market:

• Industry-average flat pricing sits around 1.5–1.7% plus terminal rental of roughly $20–35/month — note this is an industry estimate, not a published Shift4 rate [3].
• Sharper flat rates exist: fintech flat rates around 1.27–1.45% ex-GST, and bank "simple rates" from ~1.0% ex-GST plus rental, were current as at June 2026 [3].

So the same $40,000 merchant is realistically choosing between roughly $400/month (sharp end: ~1.0% + rental) and $680/month (soft end: 1.7%) — a $3,400/year spread decided entirely by where they land. The forecast isn't one number; it's a range, and your job is to land at the bottom of it.

Step 4 — Refine with your card mix

Debit-heavy businesses (most cafés and retail) can do better on interchange-linked pricing than a flat rate implies, because debit's wholesale cost is low — and falls further under the October interchange reforms. Credit-heavy or international-heavy mixes narrow that advantage; foreign-card loadings (e.g. +0.36% ex-GST on some providers) matter if tourists are a big share of your trade [3]. Your mix is on your statement: debit % vs credit % vs international %.

The mistakes to avoid

• Forecasting on the headline rate alone. Rental, monthly fees and minimums can add $300–400/year. Compare card processing costs.
• Assuming your provider's offer is the market. It's the incumbent's offer to a captive who didn't shop. Get two more numbers.
• Ignoring the October leverage window. Providers are competing hardest for switching merchants right now; that pricing tension won't last forever.
• Signing a long lock-in in a falling market. The RBA reforms are designed to push acceptance costs down over time [1]. Preserve the ability to reprice — favour no-lock-in terms where the totals are close.

What this means for you

Ten minutes with three statements gives you a defensible forecast: turnover × current surcharge rate as the ceiling, the market's sharp end as the floor, and your card mix to fine-tune. Walk into any provider conversation holding that range and you're negotiating; walk in without it and you're accepting.

Skip the spreadsheet: the forecast tool below builds your range, then the comparison engine ranks the major providers we track at your exact turnover and mix. Compare now →

Provider rates indicative, last verified July 2026 — verify with providers. The 1.5–1.7% figure is an industry-average estimate; Shift4's post-October pricing was unpublished at time of writing.