What is a tenth of a percent worth to you?
Your conversion rate is a number; what it is worth is a decision. This works out the rate, the revenue per session, and what one tenth of a percentage point would add in a month — which is roughly what one broken step in the buying path is costing you.
Your rate
$25,500.00 a monthIt runs in your browser: nothing you type is sent anywhere, and the arithmetic is the file this page loads — the same one our tests check against figures worked by hand.
The formula, in full
conversion % = orders ÷ sessions × 100
revenue = orders × average order value
per session = revenue ÷ sessions
one tenth more = sessions × (rate + 0.1)% × average order value − revenue
The last line is the one worth having. “Improve conversion” is not a decision; “a tenth of a percent is worth $1,700 a month” is. Use sessions rather than users, and keep both figures ex-tax, or the revenue will not match your accounts.
Two of them, computed rather than typed.
Both are produced by the same file the calculator above uses, so an example here cannot disagree with the tool beside it. Every figure is checked against hand-worked arithmetic in our test suite.
20,000 sessions, 300 orders, $85 average
sessions 20000 · orders 300 · aov 85 · targetRate 2
A tenth of a percent is 20 more orders a month here. That is what fixing one broken step is worth.
4,000 sessions, 28 orders, $240 average
sessions 4000 · orders 28 · aov 240 · targetRate 1.2
A high-value, low-traffic store: the same tenth of a percent is only 4 orders, but they are worth more each.
Straight answers.
What counts as a good conversion rate?
For most ecommerce stores, somewhere between 1% and 3%, and the number is nearly useless on its own: a $2,000 product converting at 0.4% can be a better business than a $20 one at 4%. What this page gives you instead is what a change is worth, which is the figure a decision needs.
Sessions or users?
Sessions. A user who visits three times and buys once converted on one of three sessions, and the session figure is what every analytics tool reports as its default. Mixing the two is the most common reason a conversion rate looks mysteriously high.
Why does a tenth of a percent matter?
Because it is usually achievable and nobody prices it. At 20,000 sessions and an $85 order, a tenth of a point is 20 orders and $1,700 a month — roughly what one broken step in the buying path costs you, and roughly what fixing it is worth.
My rate dropped and nothing changed.
Something changed. In our own nightly data the usual culprits are a theme update that broke add-to-cart on one device, a popup that covers the button on a phone, a payment method that stopped appearing, or a discount code the checkout started rejecting. All four leave the homepage working perfectly, which is why they go unnoticed for weeks.
Sessions are steady but my conversion rate fell: bad traffic or a broken checkout?
Short answer (25 October 2026): steady sessions with a falling rate points at the store, not the traffic. Bad traffic drops the rate slowly and shows up as a changed country, device or landing-page mix in analytics; a broken step drops it overnight and shows a cliff on one device or one page. Place a real order on a phone in a private window, discount code included, then check that add-to-cart reached your pixel. When Bilby visited 1,483 public Shopify stores on 1–2 September 2026, 37.7% had a broken or degraded buying path on the night (Bilby data report, read 25 October 2026). The 15-minute diagnostic walks the four checks in order.
Does this store my numbers?
No. The arithmetic runs in your browser and nothing you type is sent anywhere — there is no request to make. Only an anonymous count that the tool was used.
A tenth of a percent is usually a broken step.
The free scan walks your buying path in a real browser, on desktop and a phone, and shows you the step that fails with the screenshot. No account, three a day.
Where to go from here
- The free store scan — it walks home → product → cart → checkout in a real browser and shows you which step fails
- Profit margin — what each of those extra orders is actually worth after costs
- Why sales drop suddenly — the 15-minute diagnostic, in the order worth checking