What does checkout drop-off cost you?
Three numbers from your analytics turn a drop-off rate into a pound figure, with the usual places checkouts lose people beside it.
Out of every 100 started
CompletedLeft at checkout
Started, not finished, a month
£58,500
900 orders that got as far as paying.
Over a year
£702,000
Each point of completion is worth £1,300 a month at these numbers.
Where checkouts usually lose people
- Delivery cost or date shown late, at the last step
- An account required before paying
- A payment method missing, or failing on one browser
- Too many fields, or the form clearing on an error
- A slow checkout page on a phone
- No trust signals near the pay button
Not every unfinished checkout is recoverable: some people are comparing prices. The figure is the size of the gap, not a promise.
Calculated in your browser. Nothing is sent anywhere.
Source: Baymard Institute, US shoppers who abandoned, September 2025
Why people leave at checkout
- Extra costs too high: delivery, tax and fees
- 40%
- Delivery was too slow
- 20%
- Didn’t trust the site with their card details
- 19%
- The site wanted them to create an account
- 18%
- Checkout too long or complicated
- 17%
- The site had errors or crashed
- 17%
- Couldn’t see the total cost up front
- 12%
- Not enough ways to pay
- 9%
How the figure is worked out
Three numbers you already have
Checkouts started and orders placed both come from your analytics: in GA4 they’re the begin_checkout and purchase events, and Shopify shows sessions that reached checkout in its conversion funnel. Divide orders by checkouts started for the completion rate. The calculator multiplies the checkouts that didn’t finish by your average order value. Some of those people were never going to buy that day, so read it as the ceiling and then look at where they stop.
COULLWORKS
Worked example, the calculator’s defaults
Checkout gap
- Checkouts started a month2,000
- Not completed45%
- Orders left at checkout900
- Average order value£65
A month£58,500
The size of the gap, not a promise
Have the checkout looked at →
Where to look first
Baymard’s checkout research found the average US checkout shows 23.48 form elements, where 12 to 14 are enough
They put the conversion gain from better checkout design at 35.26% for a large site. That’s their benchmark across the stores they test, not a forecast for yours. It does say where to start: the fields nobody needs, costs that appear at the last step, and the account people are made to create before they can pay.
Most of those fixes are small. Finding which ones apply to your checkout is the work.
Can every lost checkout be won back?
No.
Some people are comparing prices or checking a delivery date with no plan to buy that day. The big figure is the ceiling. The slider shows what a realistic few points would be worth.
Where do I find checkouts started?
In GA4, count the begin_checkout event over a month, and the purchase event for orders. In Shopify, the conversion funnel on the Analytics page shows sessions that reached checkout and sessions that converted. Use the same month for both numbers.
What’s a normal completion rate?
It depends on what you sell and who buys it. Baymard’s 70.22% is cart abandonment, from basket to order, averaged across 50 studies, so it isn’t the same measure as this. The comparison that tells you most is your own: phone against desktop, and this year against last.
Is anything I type sent anywhere?
No. The sums run in your browser, and nothing is stored or sent.
What would fixing it involve?
Usually a handful of small changes: delivery costs shown before the last step, guest checkout, the payment methods your customers expect, fewer fields, and a checkout that loads quickly on a phone. A health check on the checkout finds which of them apply to you, and in what order.
The health check
When you want the cause
Find where they stop, and why
The calculator sizes the gap. The audits find it: the health check reads one path such as the checkout, the visual audit every template, and the backend audit the analytics and code behind the numbers.
Fixed prices, excluding VAT. The complete audit is quoted.