Ecommerce Transaction Fees Explained: The Real Math on What Platforms Take

On most ecommerce platforms, every sale is split three ways: the card networks take ~2.9% + 30¢, the platform may take an extra transaction fee of 0.5%–2%, and marketplaces take 8%–15% or more. The card cut is unavoidable. The platform cut usually isn't — and on a store doing $20,000/month it's the difference between keeping your margin and quietly handing over $4,800 a year.

The three layers of fees on every sale

When a customer clicks "buy," the money doesn't arrive whole. It passes through up to three tolls before it reaches you:

• Payment processing — roughly 2.9% + 30¢ per card transaction. This goes to Stripe, the card networks, and your bank. Nobody escapes it, on any platform.
• Platform transaction fees — an additional cut some platforms charge on top of processing, just for using their software. This is the one people miss.
• Marketplace commission — if you sell on Amazon, Etsy, or eBay, a referral or final-value fee of 8%–17% comes off the top of each sale.

The first layer is a cost of doing business. The second and third are where platforms make their real money — and where you have the most room to keep more of yours.

The real math: what a $100 sale actually nets you

Numbers make this concrete. Take a single $100 order and follow it through each option. We'll assume standard card processing of 2.9% + 30¢ ($3.20) applies everywhere, then add the platform's cut.

• Shopify Basic (using a third-party gateway instead of Shopify Payments): 2.0% platform fee = $2.00 on top of processing. You net ~$94.80.
• Shopify with Shopify Payments: the extra transaction fee is waived, but you're locked to their processor. You net ~$96.80 — good, until you want a different gateway.
• Etsy: 6.5% transaction fee + payment processing + a 15% "Offsite Ads" fee if that sale came from an ad. A typical order nets ~$84–$90, and less if ads are involved.
• Amazon: ~15% referral fee, before FBA storage and fulfillment. You net ~$85 or less before shipping costs.
• A 0% transaction fee platform (like Shopswired): only the unavoidable ~$3.20 in processing. You net ~$96.80 — and you're free to negotiate your own processing rate as you grow.

On one order, the gaps look small. That's exactly why transaction fees are dangerous: they're invisible per sale and enormous per year.

Why the percentage matters more than the subscription

A monthly subscription is a fixed cost. You can plan around it, and it doesn't grow when you do. A transaction fee is the opposite — it's a percentage of everything you sell, so it scales in lockstep with your success. The better your store performs, the more the platform earns for doing nothing new.

Run the annual math on a platform charging a 2% transaction fee, separate from card processing:

• $5,000/month in sales → $1,200/year in platform fees
• $20,000/month in sales → $4,800/year
• $50,000/month in sales → $12,000/year

That $12,000 isn't buying you better software than the store next door paying 0%. It's a tax on your growth, and it comes straight out of margin you already earned.

The honest trade-offs

No platform is free, and it's worth being clear about what you're actually trading:

• Marketplaces buy you traffic. Amazon and Etsy's high fees include access to millions of ready-to-buy shoppers. If you have no audience yet, that reach can be worth the cut — but you never own the customer relationship, and you're one policy change away from losing your storefront.
• Bundled processing hides the fee, not the cost. Waiving the platform fee when you use the in-house processor sounds generous, but it locks your rate. Once you're doing real volume, you can't shop around for cheaper processing.
• 0% transaction fees put you in control. You pay for the software and keep every dollar past processing — and you're free to bring your own gateway and negotiate rates as you scale.

The right answer depends on your stage. Early on, a marketplace's audience may justify its fees. But once you have your own traffic, paying a percentage of every sale to a platform is pure leakage. We broke down the full picture — subscriptions, apps, and hidden costs — in how much it costs to run an online store in 2026.

How to keep more of every sale

You can't dodge card processing, but you can stop paying twice:

• Choose a platform with 0% transaction fees. This is exactly why we built Shopswired without them — beyond standard processing, you keep 100% of every sale.
• Own your traffic. The more sales come from your own site instead of a marketplace, the more of each order you keep.
• Read the fee schedule, not the headline price. The sticker subscription is rarely the number that decides your annual profit — the per-sale percentage is.

The bottom line

Transaction fees are the quietest line item in ecommerce and one of the most expensive. A 2% platform cut is invisible on a single order and worth thousands a year across your revenue. Control the two things that matter — keep fixed costs lean and refuse to pay a percentage tax on your own growth — and the money you save can fund your entire marketing budget.