How are softwood lumber duties calculated, and what data do you need?

As a deposit first and a final assessment later. At entry, the importer pays a cash deposit: the entered value times the antidumping and countervailing deposit rates in force for that producer, or the rate for non-selected companies. The entries are held unliquidated. An annual administrative review later sets final rates for that period, producer by producer, and the entries are liquidated at those rates. The difference is refunded or billed, with interest either way. To reconcile, a business needs, for each entry, its date, entered value, producer and exporter, deposit rates and amounts, review period and liquidation status.

What the usual answer says

Most explanations give duties as a combined percentage of entered value, from antidumping and countervailing rates, with company-specific or all-others rates. That describes the deposit. It leaves out the true-up, which is where the money moves, and which can go either way.

Deposits now, assessment later

The preliminary countervailing results for the latest review, published on 14 April 2026, cover entries made "January 1, 2024, through December 31, 2024". The notice explains that "normally, upon completion of an administrative review, the suspended entries are liquidated at the CVD assessment rate for the review period". Assessment instructions go to the customs agency "no earlier than 41 days" after final results. The review set a rate for "215 non-selected companies" and found that 56 producers or exporters "had no reviewable shipments, sales, or entries". The antidumping preliminary results of the same day set 10.66% for non-examined companies, and the countervailing notice 14.17%: 24.83% combined.

A builders' association, NAHB, which opposes the duties, reported this as "bringing the combined rate down from 35.16% to 24.83%". The 35% is the rate set by the previous review's final results: 20.56% antidumping (29 July 2025) and 14.63% countervailing (12 August 2025) for non-selected companies. Those add to 35.19%, not the 35.16% NAHB gives. It applies to entries made after those dates. It is not what 2024 entries paid.

What 2024 entries actually paid

From 19 August 2024, deposits were set by the final results for the 2022 period. Non-selected companies faced 7.80% antidumping as first published, later amended, and 6.74% countervailing: about 14.5% combined. Entries earlier in 2024 paid rates from the review before that, not given here.

So for a non-selected producer's lumber entered in, say, October 2024 at an entered value of 100,000, the deposit was about 14,540. If final rates match the preliminary 24.83%, the assessed duty is 24,830, and the importer owes about 10,290 more. The figures are illustrative; the rates are from the notices. The statute adds that "Interest shall be payable on overpayments and underpayments of amounts deposited", which on a two-year gap is not small.

The headline fall from 35% to 25% therefore compares two periods' rates. For 2024 entries, the preliminary results point to a bill. For 2025 entries, deposited at around 35%, a later review could point the other way. NAHB expected final results for the 2024 period within 120 days of April. Check for the final notice before booking anything.

The data to keep

For each entry, keep the entry number and date, entered value, and volume with its count basis, nominal or net. Add the producer and exporter as declared, the tariff code, the deposit rate and amount for each order, and the review period. For each review, the preliminary and final rates by producer and the publication dates. For each entry after final results, the liquidation date, the assessed amount, the difference and the interest. Volume basis matters beyond duties. The Softwood Lumber Board's assessment rule of 22 September 2026 notes that lumber counted by net size has to be converted, with the nominal rate "multiplied by 1.503" for a net count.

The sector tariff on softwood lumber, a "10 percent additional ad valorem rate of duty" under customs guidance of October 2025, is a separate layer with no review-based true-up. Keep it apart from the deposits.

Accrue when the preliminaries publish

Most importers of record already receive liquidation notices, and their counsel follows the reviews. The finance question is timing. When preliminary results publish, a business can estimate the bill or refund on every open entry, with interest, and accrue it, rather than waiting two years for liquidation. That changes the cost of lumber already sold and the price of lumber still to be sold.

When it doesn't apply

Businesses that buy duty-paid lumber from a domestic distributor carry no deposit themselves, though their supplier's true-ups may reach their prices.

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