The #1 cause of peak season shipping disputes isn’t weight
4.3% of peak season shipments trigger surcharges you don’t see until it’s too late.
See what’s really behind rising costs, and how to get ahead of them in 2026.
This isn’t a forecast. It’s a repeat.
Peak season 2025 already showed where shipping costs surge. The same triggers are back for 2026, and in several cases, the bill is already confirmed to be higher.
This report breaks down what happened last peak season, carrier by carrier, and what it means for 2026.
What’s inside the report
- The surcharges most likely to catch retailers off guard during peak, since address and zone errors generate over 6x more support tickets than weight
- Peak season surcharge schedules for FedEx, UPS, DHL, Royal Mail, Parcelforce, DPD, and Evri heading into 2026
- Why cost per shipment forms a completely different curve in the US than in the UK, and what that means for retailers shipping in both markets
- The real gap between domestic and international shipping costs, with FedEx’s nearly 11x and Royal Mail’s nearly 21x
- Five concrete moves to reduce exposure before the season starts
Peak shipping costs rarely match the sticker price
Linnworks and Shippo data from 2025 shows address and zone errors were the leading cause of peak season shipping support tickets, generating more than six times as many tickets as weight misclassification. Cost per shipment didn’t rise in a straight line with weight either. In the UK, parcels over 20kg cost nearly 17 times more than the mid-weight rate, while the US followed a completely different pattern. Heading into 2026, several of the surcharges behind these costs, including UPS’s Mail Innovations fuel surcharge and Royal Mail’s fuel and international surcharges, have already gone up.
This report was built in partnership with Shippo, using aggregated peak season 2025 shipping data from both Linnworks and Shippo.