Step 1
Save at least two workspace calculations
Each record must belong to the signed-in user and workspace. Public-by-link records cannot be pulled into a private comparison merely because someone knows the link.
After the first saved result, Start second calculation can use that historical record as a safe starting point. Only HTS code and origin carry forward; current shipment facts start blank.
Step 2
Choose calculation A and calculation B
Open Compare from the workspace and select two different records. The comparison verifies the stored snapshot hashes before presenting differences.
Step 3
Read input and component changes separately
Input differences show changes such as value, origin, date or fee assumptions. Component differences show stored base duty, supported additional duties and fees. A changed total may have several simultaneous causes.
- Review data-version differences before attributing a change to a tariff update.
- Review warning differences before treating either result as complete.
- Open each source/evidence page for the original calculation context.
Step 4
Use comparison as evidence, not a binding conclusion
The report helps identify what changed between TariffCalc records. It does not determine legal causation, validate a customs entry or replace a broker or binding ruling.