E-commerce is a numbers game. A 1% improvement in conversion rate can mean millions in additional revenue. This guide covers the 25 highest-impact A/B tests for online stores, organized by funnel stage with expected impact and implementation difficulty.
E-commerce Conversion Reality Check
2.5%
Average conversion rate
70%
Cart abandonment rate
$260B
Lost to cart abandonment/yr
5%+
Top performers achieve
The gap between average (2.5%) and excellent (5%+) represents a 100% revenue increase from the same traffic. A/B testing is how you close that gap.
Product Page Tests (5 Tests)
1 Product image size and zoom
High ImpactLarger images with zoom can increase conversions 20-40%
2 Review placement above fold
High ImpactMoving star ratings near price increases trust signals
3 Add to cart button color/size
Medium ImpactHigh-contrast, larger buttons improve click rates
4 Urgency elements (stock count)
High Impact"Only 3 left" creates FOMO and speeds decisions
5 Social proof badges
Medium Impact"Bestseller" or "10,000+ sold" builds confidence
Deep Dive: Product Image Optimization
Product images are the #1 factor in e-commerce conversion. Here's what to test:
Image Size
Test 500px vs 800px vs full-width. Larger images increase conversion but may slow load time.
Number of Images
Test 3 vs 5 vs 8+ images. More angles reduce returns but may overwhelm.
Video Integration
Product videos can increase conversion 80%+. Test autoplay vs click-to-play.
Lifestyle vs Product
Test pure product shots vs lifestyle context. Fashion often benefits from lifestyle.
Pro tip: Always test image changes with mobile specifically. What looks great on desktop may be too small on mobile.
Checkout Optimization (5 Tests)
6 Guest checkout option
Very High ImpactRequired account creation kills 35% of checkouts
7 Progress indicator
Medium ImpactShows customers how close they are to completion
8 Trust badges placement
High ImpactSecurity badges near payment fields reduce anxiety
9 Form field reduction
High ImpactEvery unnecessary field costs 3-5% conversion
10 Express payment options
Very High ImpactApple Pay/Google Pay can lift mobile conversion 10-20%
Cart & Abandonment (5 Tests)
11 Free shipping threshold
Very High Impact"$15 away from free shipping" increases AOV 15-25%
12 Cross-sell recommendations
High Impact"Frequently bought together" adds 10-30% to AOV
13 Cart abandonment timing
High ImpactTest 1hr vs 4hr vs 24hr for recovery emails
14 Exit intent offers
Medium Impact10% off popup on exit can recover 5-10% of abandoners
15 Persistent cart
Medium ImpactSaved carts across sessions improve return conversion
The Free Shipping Threshold Test
This is often the highest-ROI test for e-commerce. Here's how to find your optimal threshold:
Let's say it's $45
Test $55, $60, $65 thresholds
"You're $12 away from FREE shipping!" with progress bar
Typical Results
15-25% increase in AOV, with 5-10% of customers adding items specifically to reach the threshold. The shipping cost is usually offset by the margin on additional items.
10 More High-Impact Tests
Your E-commerce Testing Roadmap
Start with the highest-impact, lowest-effort tests: guest checkout, free shipping threshold, and product image optimization. These alone can lift conversion 20-30% for most stores.
Remember: in e-commerce, small percentages mean big money. A store doing $1M/year that improves conversion from 2% to 3% just added $500K in revenue. Start testing today.