Required facts
Source-backed US fee tool
Harbor Maintenance Fee calculator
Estimate HMF only after confirming covered commercial-vessel cargo at a subject US port. The tool does not infer vessel, port, exemption or special-rule facts.
Educational estimate
Confirm the facts to see an amount.
The same date-effective fee table powers this tool and the main duty calculator.
Formula
How the HMF estimate works
For explicitly confirmed covered cargo, the bundled rule multiplies the entered value by 0.125 percent and rounds the amount to cents.
Boundary
Applicability is not determined from “ocean” alone
Covered port use, commercial-vessel cargo, exemptions and special movements matter. If applicability is uncertain, the main calculator excludes the amount and marks the fee assumptions for review.