Yes, buy now, pay later (BNPL) usually helps conversion, but by less than Klarna and Afterpay marketing suggests.
The best independent evidence, a randomized trial at a German online furniture retailer, found that offering BNPL raised sales by 20%, mostly by winning buyers who would not have bought at all.
In our database, the gains from BNPL messaging range from +1.36% checkout completion to +25.2% revenue per session, and where you put the message matters as much as whether you offer it.
This page pulls together the BNPL tests in LiftArchive, separates provider claims from controlled evidence, and shows how to test Klarna, Afterpay, Shop Pay Installments or PayPal Pay Later on your own store.
For the wider topic of payment buttons, see our payment icons and express checkout hub.
What the evidence says about BNPL conversion rates
There is no single "Klarna conversion rate." What you can measure is how much your store's conversion rate, order value and revenue per visitor change when you add BNPL or make it more visible.
Three kinds of evidence answer that, and they are not equally strong.
Controlled research
The cleanest study is Berg, Burg, Keil and Puri, published in the Journal of Financial Economics in 2025.
The authors used a randomized control trial in which a German e-commerce furniture company made BNPL available to randomly selected customers.
The product was a single deferred payment, similar to a "pay in 30 days" scheme (the bill was due 14 days after delivery), not pay-in-four.
Their findings, from the NBER working paper:
- Making BNPL available increased sales by 20%.
- 60-70% of that effect came from extra buyers (the extensive margin). The rest came from people spending more per order.
- Purchases by low-creditworthiness customers were two to three times as responsive as purchases by high-creditworthiness customers.
- The benefits to the merchant clearly outweighed the costs of the subsidized loan.
A second paper, Di Maggio, Williams and Katz (NBER, 2022), used US transaction data and found that BNPL access increases total spending and the share of spending that goes to retail.
That supports the idea that BNPL creates new spending rather than only moving it from cards.
Provider claims
Provider numbers are much bigger. The US Consumer Financial Protection Bureau's 2022 BNPL market report quoted lender marketing to merchants such as "30% increase in conversion," "41% increase in average order value" and "85% higher merchant AOV compared to other payment methods."
Treat these as the top of the range.
They usually compare BNPL users with non-users, who are different people, and they come from companies selling the service.
They are not A/B tests of your store with and without BNPL.
A/B tests from our database
Our tests sit between the two: real stores, real traffic, but often bundled changes and missing sample sizes.
The table below lists every BNPL-related test we have.
| Test | Change | Result | Ran by |
|---|---|---|---|
| Enabled Shop Pay | Turned on Shop Pay with pay-later on a store that had never offered it | Conversion rate moved from below 1% to above 1% | Dave Diederen |
| Luxy Hair installments messaging | Shop Pay Installments plus earlier installment messaging, bundled with duties tests | +16.5% transactions, +25.2% revenue per session, +13.3% add-to-cart rate | Prismfly |
| Shiseido / NARS Klarna copy | Grouped price, Klarna copy and Add to Cart | Desktop +159% Add to Cart clicks; mobile +129% | Shiseido |
| BLACKROLL PayPal Pay in 30 days | "Pay in 30 days" near the PDP price plus PayPal Express | +2.2% revenue per user, +€35.0K during the test | DRIP Agency |
| schuh Klarna eligibility | Said at delivery choice whether Klarna works with each method | +1.36% checkout completion | schuh |
| Gym King Klarna vs Trustpilot | Klarna messaging instead of a 4.5-star Trustpilot rating | Klarna messaging won (no figure given) | Gym King |
| Checkout image with financing | Checkout image covering social proof, returns and financing | +$55,000/month | Milos |
Prismfly
DRIP Agency
@DaveDiederenEvery test in the table won, but read that with care.
Stores publish wins more often than losses, and several of these results bundle BNPL with other changes.
The honest summary: adding or surfacing BNPL is one of the more reliable payment tests, with realistic revenue effects in the low single digits to the mid-20s percent.
Where BNPL conversion gains come from
BNPL lifts conversion through two routes, and knowing which one applies to your store tells you how big a lift to expect.
New buyers who could not or would not pay in full
The Berg study found that most of the sales gain came from people who would not otherwise have bought, and that lower-credit customers responded most.
The authors describe BNPL as a subsidized loan bundled with the product, which works like a lower price for customers who are short on cash.
So expect bigger effects where the order value is high relative to your customers' budgets and where your buyers skew younger or more credit-constrained.
Dave Diederen's Shop Pay test is a good example: the store had been stuck below 1% conversion after a full redesign, and turning on pay-later moved it above 1% because, as Dave Diederen put it, the audience wanted BNPL and had never been offered it.
A smaller-looking price
Showing "4 payments of $25" next to a $100 price changes how the price is perceived, which is a framing effect.
It can also shift which number becomes the anchor.
This is why the placement of the message matters, and why many BNPL tests are really copy and layout tests.
Gym King's test shows how strong this can be for its audience: Klarna messaging beat a 4.5-star Trustpilot rating in the same slot, and the case study notes that BNPL later reached 45% of purchases.
No lift figure was published, so treat it as a direction, not a size.
Does Afterpay or Klarna increase conversion more?
We have no head-to-head A/B test of Klarna against Afterpay, and we have not found a published one we trust.
Provider-to-provider comparisons you see online come from the providers or their partners.
What the tests do show is that the provider brand matters less than three things you control:
- Which brand your customers already use. Gym King, schuh and Shiseido all tested messaging for a provider they already offered. Check your own checkout data, or ask customers, before picking a provider.
- The product type. Pay-in-four suits orders roughly in the $50-$1,000 range the CFPB describes as typical. A single "pay in 30 days" deferral, like the PayPal option BLACKROLL tested and similar to the product in the Berg study, suits buyers who want to try before paying.
- Visibility before checkout. Most of our winning tests moved BNPL messaging earlier, onto the product page or delivery step, rather than just enabling it at payment.
If you are choosing between providers, test the one your customers recognize first.
Adding a second BNPL brand to the same page rarely adds much and adds clutter, so test that separately.
Where to show BNPL messaging
Placement is the most testable part of BNPL.
Klarna's own on-site messaging docs advise putting the placement "close to the product price or cart total," and our data backs that up.
- Next to the price on the product page. Shiseido grouped the price, Klarna copy and Add to Cart button together and saw +159% Add to Cart clicks on desktop and +129% on mobile, plus +72% and +24% payment option clicks. These are click metrics with no sample size, so they overstate the revenue effect, but the direction is clear.
- Early in the journey, not only at payment. In Prismfly's Luxy Hair work, BNPL options had only been visible at checkout. Showing installment value earlier was part of a workstream that produced +25.2% revenue per session, though that figure covers the whole workstream, including duties tests.
- At the step where eligibility gets confusing. schuh added a short note at delivery selection saying whether Klarna worked with each delivery method. That small fix lifted checkout completion by 1.36%.
- In a checkout reassurance block. Milos added an image to a car parts store's checkout covering social proof, return policy and financing, reported at +$55,000/month. Financing was one of three messages, so the BNPL share is unknown.
Shopify merchants can show Shop Pay Installments banners on product and cart pages.
Shopify's help center lists eligible orders of $35 to $30,000 USD in the United States and £50 to £30,000 in the UK, so hide the message on items below the minimum.
For more on the surrounding layout, see our tests on product page payment messaging and checkout payment options.
Costs and risks that offset the lift
A conversion lift is not the same as more profit.
BNPL has three costs that a conversion-rate test will not show.
- Merchant fees. The CFPB report found that merchant discount fees averaged 2.49% of gross merchandise volume in 2021 across the five lenders it surveyed, down from 2.91% in 2020. Compare that with your card processing rate: a shopper who would have paid by card anyway may now cost you more. Check your own provider's current rates.
- Cannibalization. If most BNPL orders come from people who would have bought anyway, revenue per visitor barely moves while fees rise. The Berg study measured this substitution and still found BNPL profitable, but that was one merchant.
- Returns. The CFPB found that 13.7% of BNPL loans in 2021 had at least part of the order returned. Compare return rates by payment method before declaring a win.
Rules are also changing. In the UK, BNPL lending comes under FCA regulation from 15 July 2026, as Linklaters summarizes.
If you sell in the UK, check your BNPL messaging wording with your provider before you test new copy.
How to test BNPL on your own store
Most stores cannot run a clean "BNPL on vs off" test at the payment step, because payment methods are set at the account level.
You can, however, test the messaging, which is where most of the lift in our database comes from.
- Pick revenue per visitor as the main metric. Conversion rate alone misses fee costs and order value changes. Use revenue per visitor, then check margin after fees.
- Test placement first. Control: BNPL shown only at checkout or as a small logo. Variant: installment amount next to the product price. This mirrors the Shiseido and Luxy Hair tests.
- Segment by order value. Expect larger effects on higher-priced products. Report results above and below your BNPL minimum separately.
- Watch mobile separately. Payment UI can backfire on small screens. In one Blend Commerce test, swapping payment icons for express checkout on a travel brand's PDP cut mobile conversion by 14%, and Clean Commit's payment options in the mini cart test was inconclusive at +1.7%.
- Size the test properly. A realistic BNPL messaging effect is a few percent. Check you have enough traffic to detect an effect that small before you start.
- Check returns and fees after the test. Pull BNPL order share, return rates by payment method, and provider fees for both arms.
If you want a second opinion on a BNPL test plan, the practitioner below runs payment and checkout tests for ecommerce stores.
For more ideas beyond payment options, browse all tests or start from our CRO guide.