Guides and methodology
How Cartroute compares prices, what shipping does to the ranking, and how far to trust a coupon code, measured across the whole catalog.
Updated September 15, 2026
How does Cartroute decide which retailer is cheapest?
The effective-price method: listed price plus shipping minus the best coupon anyone can use, restricted to fresh, in-stock offers.
By Grace Oduya, Head of Data
Updated September 18, 2026
How often does shipping change which retailer is cheapest?
Measured across the full Cartroute catalog: how often the lowest sticker price is not the lowest landed price.
By Maya Lindqvist, Co-founder and CEO