Customs duty estimate from declared value and category rate

It returns the matched rate and estimated duty, making the calculation easy to inspect and reproduce. The tool does not guess classifications, retrieve government tariffs, add taxes, or decide whether a shipment qualifies for an exemption. Use the rate and declared value applicable to your shipment, then treat the result as a planning estimate rather than a customs assessment.

Prepare the declared value and category table

Start with the declared value that should be used as the duty basis for your planning scenario. Enter it as a nonnegative number, without a currency symbol or thousands separator. Then provide a rate table in which every row has a unique category name and a nonnegative rate_percent value. The category submitted for the shipment must match one table row exactly, including capitalization and spacing. Exact matching prevents the calculator from silently selecting a similar but legally different classification. Rates belong in percentage form: a rate_percent of 7.5 means seven and a half percent, not the decimal 0.075. Keep every monetary amount in the same currency. The calculator does not convert currencies because no exchange-rate source is consulted. Before calculating, verify that the declared value, category classification, and rate table come from sources appropriate to the destination country and shipment date. Tariff schedules, valuation rules, origin preferences, and exemptions can change the applicable basis or percentage, so the quality of the estimate depends on the inputs you supply.

Understand the calculation and result

The estimator searches the supplied table for the exact category, takes that row's duty rate percentage, and multiplies the declared value by the rate divided by one hundred. For example, the underlying relationship is estimated duty equals declared value times rate_percent divided by one hundred. The result includes the original declared_value, the matched category, duty_rate_percent, and estimated_duty so that another person can audit the inputs without reconstructing the lookup. No rounding is imposed by the algorithm. This preserves the deterministic arithmetic result and avoids pretending that every customs authority uses the same minor-unit or rounding convention. Your invoicing or compliance process can round afterward under the applicable rules. A zero rate produces zero estimated duty, while a zero declared value also produces zero. If the requested category is missing, the operation returns an invalid-input error instead of assuming a default rate. Duplicate category rows are rejected as ambiguous, even when their percentages happen to agree, because a table should provide one authoritative rate per category.

Use the estimate within a landed-cost workflow

Use this result as one component of a landed-cost model, not as a final amount payable to customs. Actual import charges may also include import VAT or sales tax, excise duty, anti-dumping measures, brokerage, handling, disbursement fees, minimum charges, and destination-specific assessments. Some authorities calculate duty on a customs value that includes freight, insurance, assists, royalties, or other adjustments rather than the invoice value alone. Preferential origin rules or de minimis thresholds may reduce the charge, but eligibility requires facts this calculator does not collect. For procurement planning, store the supplied rate table beside the estimate so reviewers know which assumption was used. For catalog operations, run one estimate per item or classification and aggregate only after confirming whether customs treats the shipment at line or consignment level. Recalculate whenever the product classification, declared value, origin, destination, currency basis, or effective tariff schedule changes. The browser calculation is convenient for manual checks, while the API costs $0.002 per request when you automate scenarios in checkout, sourcing, or reporting systems.