Technical Logistics Tool

Universal Checksum Validator

Verify if a tracking number is mathematically valid according to international standards for FedEx, DHL, Post/EMS, and more.

How Checksum Validation works

Logistics companies use mathematical algorithms to generate the final digit of a tracking number. This helps detect typos or data entry errors before a parcel is processed. If the checksum is invalid, your tracking number is likely incorrect.

Detailed UPS 1Z Validator

For specialized UPS 1Z tracking numbers, use our high-precision validator below.

Walidator sumy kontrolnej UPS

Wprowadź pełny numer śledzenia 1Z. Walidator sprawdza, czy ostatnia cyfra odpowiada obliczonej sumie kontrolnej.

How Checksums Work

Logistics companies use mathematical algorithms to generate the final digit of a tracking number. This helps detect typos or data entry errors before a parcel is processed. A valid checksum means the number is mathematically correct, though it doesn't guarantee the parcel has been shipped yet.

UPU S10 (Postal Standard)

Standard international postal numbers (e.g., RR123456785KR) use a Modulo 11 weighting system (8, 6, 4, 2, 3, 5, 9, 7) to calculate the 9th digit.

FedEx 12-Digit

Most FedEx Ground and Express numbers use a weighted Mod 11 algorithm across 11 digits to produce the final check digit.

Related

For more about UPS tracking number formats, service codes, and troubleshooting, see our complete guide to UPS tracking numbers.