Sales tracking for small business: what you actually keep per sale on each channel

If you sell in more than one place, you've probably noticed that the same product at the same price doesn't leave you the same money everywhere. Your own site, a marketplace and a simple payment link each take their cut in a different way.

Good sales tracking for small business isn't just counting orders. It's seeing profit by sales channel, so you know which place actually pays you best for the same work.

The one rule that makes channels comparable

Use the same lines for every channel:

1. Sale price
2. Channel fees (what the store or marketplace charged)
3. Payment processing (what the card processor charged)
4. Shipping you paid
5. Ad spend for the sale
6. Cost to make or buy it

What's left is what the sale kept. Some channels fold lines 2 and 3 together. That's fine; just don't count the same fee twice.

What three common channels charge (US rates)

These come from each platform's own pricing page, checked on Oct 10, 2026. Rates vary by plan, category and country. Everything below is US, standard pricing.

Your own site on Shopify. On the Basic plan, Shopify Payments online standard card rates are "2.9% + 30¢" (Grow "2.7% + 30¢", Advanced "2.5% + 30¢"). The plan itself is $29/mo on Basic paid yearly. Using a third-party payment provider adds a third-party transaction fee of "2%" on Basic.

Amazon. Two plans: Individual at "$0.99 / item sold", or Professional at "$39.99" a month. On top of that, a referral fee applies: "For every item sold, you'll pay a percentage of the total price or a minimum amount, whichever is greater." It varies by category; for example "Everything Else" is 15% with a $0.30 minimum, and "Footwear" is 15%. Amazon notes that an item's total price "includes its list price, as well as shipping costs and any gift-wrapping charges." Fulfillment by Amazon (FBA) costs extra and isn't included here.

A Stripe payment link or checkout. Stripe lists "2.9% + 30¢ per successful transaction for domestic cards", with no monthly fee on standard pricing.

One $40 sale, three channels

Example (made-up round numbers). One item sells for $40.00 to a US customer. The seller pays $5.00 shipping, spent $3.00 on ads for this sale, and the item cost $10.00 to make. Those three costs total $18.00 on every channel.

Own site (Shopify Basic, Shopify Payments)

• Processing: 2.9% × $40.00 = $1.16 + $0.30 = $1.46
• After fees: $40.00 − $1.46 = $38.54
• Kept: $38.54 − $18.00 = $20.54 (51.4% of the price)

Amazon (Professional plan, "Everything Else" category, seller ships it)

• Referral fee: 15% × $40.00 = $6.00 (above the $0.30 minimum)
• After fees: $40.00 − $6.00 = $34.00
• Kept: $34.00 − $18.00 = $16.00 (40.0%)
• On the Individual plan, add $0.99: kept $15.01

To keep the example simple, we've assumed the customer paid $40.00 in total. If the buyer also pays a shipping charge on Amazon, the referral percentage applies to that too.

Payment link (Stripe, standard US pricing)

• Processing: 2.9% × $40.00 = $1.16 + $0.30 = $1.46
• Kept: $40.00 − $1.46 − $18.00 = $20.54 (51.4%)

Same product, same price, a difference of $4.54 per sale between the best and worst channel in this example. That isn't a reason to leave a channel. Marketplaces bring buyers you might never reach on your own, and your own site has its own costs, like the monthly plan and the ads you run to send people there. It's a reason to know the number.

Monthly costs belong in their own line

Shopify's plan price and Amazon's Professional fee are monthly, not per sale. Track them separately and look at them next to each channel's total kept for the month. A channel with a $39.99 monthly fee and three sales is a different picture from one with three hundred.

What a sales tracker for small business should show

Whatever you use, a notebook, a spreadsheet or a system, a useful sales and expense tracker answers four questions each week:

• How much did each channel sell?
• How much did each channel take in fees?
• What did each sale keep after shipping, ads and costs?
• Which channel kept the most per sale, and which kept the most in total?

The last two can have different answers. Often the busiest channel isn't the one that keeps the most per sale.

Check one sale per channel

The free calculator at lunithlabs.com/calculator lets you type in one sale and see what's left after fees, ad spend and costs, on any channel you sell through. Enter the channel fee and payment processing as a percent and/or a flat amount, plus shipping, ad spend and your item cost. It shows the dollars kept, the share of the price, and each deduction. It runs in your browser and the page says nothing you type is stored. Run the same sale once per channel, with each channel's rates from your own statement, and you have your comparison.

Keeping it going every week

Once you've done this for a few sales, the next problem is doing it every week without rebuilding the math. Lunith Commerce OS is a business operating system that runs in Notion. It keeps each channel's fees on file, so every sale you log shows what it kept, by channel, in one place. It's $59.99, one time. See what's inside.

Or start right now with one sale in the free calculator.