Where to place upsells: cart bump or post-purchase.
Inputs
Comparison
Combined monthly contribution—
Cart bump revenue
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Post-purchase revenue
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AOV lift (combined)
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Per-strategy breakdown
Strategy
Attach %
Avg value
Monthly revenue
Monthly contribution
About this calculator
The cart bump vs post-purchase upsell decision isn\'t really a decision — both should run. Cart bumps catch customers who need a small nudge before checkout commitment. Post-purchase catches customers who\'ve already converted and have low resistance to one-click add-ons. The combined effect typically produces 20-35% AOV lift on a meaningful portion of orders.
This calculator compares both strategies side-by-side using your specific attach rates and average values. The math: orders × attach rate × upsell value × margin = monthly contribution per strategy. Most operators discover post-purchase produces 1.5-2× the contribution of cart bumps because of higher attach rate and typically higher upsell value, but cart bumps still contribute meaningful revenue at near-zero implementation cost.
The execution priority: implement post-purchase first (Shopify\'s native checkout extensions or OneClickUpsell / ReConvert apps). Higher impact per implementation hour. Add cart bump second — most cart pages support a simple checkbox bump natively or via app. Test 2-3 different upsell products in each placement; rotate winners quarterly. Don\'t over-stack (one bump + one post-purchase, not three each — accept rate falls when buyers feel pressured).
Pair with the AOV Uplift calculator (broader AOV strategies), Bundle Margin calculator (bundle vs upsell tradeoffs), Subscription Add-On Revenue calculator (the subscription analog), and Cart Abandonment Revenue calculator (downstream conversion). Most successful upsell programs treat the cart and post-purchase pages as testable surfaces — A/B test offers monthly, refresh creative, validate margin holds with discount mix.
Frequently asked questions
What's a cart bump?
A small upsell offer on the cart page before checkout. Usually a complementary product at modest discount ($10 off, free shipping bundle, sample add-on). Customer toggles to add. Conversion: 8-15% of cart sessions add a bump. AOV lift: 10-20%.
What's post-purchase upsell?
Offer presented after checkout completes but before the thank-you page (Shopify's native post-purchase, OneClickUpsell, ReConvert). Customer accepts with one click — no re-entering payment. Conversion: 15-30% accept. AOV lift: 15-30%.
Why does post-purchase convert better?
Frictionless. Cart bump requires re-evaluation during checkout (cognitive load, second-thoughts on price). Post-purchase already converted — buyer is in commitment mode, one-click adds without payment friction. The psychological state is different.
Can I run both?
Yes — and most successful brands do. Cart bump catches customers who would have abandoned without the offer. Post-purchase catches customers who already converted. Combined attach rate: 25-40% on customers seeing both. Don't over-stack — one bump + one post-purchase upsell, not three of each.
Best products to upsell post-purchase?
Higher-ticket complements (you bought $40 product → "Want the $80 deluxe version for +$25?"), warranty/protection plans, bulk add-on of consumables (you bought 1 → "Add 2 more at 20% off"), or related accessories. Don't upsell completely unrelated products — accept rate plummets.