How is a duty drawback refund calculated?

The steps:

1. Duty per unit. The duty paid on the import line divided by its quantity, for each program on that line: ordinary duty and any Chapter 99 duty, such as Section 301.
2. Matched quantity. The units exported or destroyed that match that line.
3. 99%. Multiply duty per unit by the matched quantity, then by 99%.
4. Fees. Add the line's share of the merchandise processing fee, apportioned by relative value, and harbor maintenance tax where it applies.

5. Caps. For substitution, use the lesser of the import duty and the duty the exported article would bear if imported.

   For exports to Canada or Mexico, apply the USMCA lesser-of cap, unless the goods were exported in the same condition as imported.

Drawback is computed on final liquidated duties, and IEEPA lines wait for the sequencing check.

A claim computed above 99% isn't paid until it's corrected.

The agent's arithmetic is ordinary code, not AI, and it re-foots each claim to the CBP 7501 totals to the cent.

Your broker reviews every line. See the sample CSV built from the demonstration file (synthetic data).