One is the rate a government publishes ahead of time. The other is what one specific box owes once that rate meets it.
What each word means, as the carriers define it
UPS keeps both terms in the same alphabetical glossary, one entry after the other, and reading them back to back explains most of the confusion on its own:
“Duty: A government tax imposed on imported goods.”
“Tariff: A government imposed tax on goods entering or exiting the country.”UPS, Glossary of Terms, ups.com, read 2026-08-28
Read literally, those two lines describe almost the same thing: a government, a tax, goods crossing a border. That is not a drafting accident. Inside one trade transaction the tariff and the duty are the same money, seen at two different moments. The rate is the tariff. What lands on a customs clearance sheet once that rate has met a real, valued, classified shipment is the duty.
How a duty amount actually gets built
DHL's explainer on the subject draws the line a little sharper than a glossary entry can. It defines import duty as “a tax collected by customs authorities on all goods sold across borders,” then names tariffs as one of several mechanisms that produce that tax, alongside excise duties and other border charges — not as another word for the same single thing.
The same page names what actually decides the number on one specific shipment: the value of the goods including insurance and shipping, the goods' own description, the country of origin, the destination country's tariff rate, and the goods' HS code. Four of those five belong to the shipment itself. Only one of them, the tariff rate, is looked up rather than measured — and it is the one word both glossaries above use for duty and tariff in the same breath.
| Question | Tariff | Duty |
|---|---|---|
| Who sets the number | The importing country's government | The same government, applied to one shipment |
| When it's fixed | Published on a schedule, revised occasionally | Worked out at the time of entry, shipment by shipment |
| What it looks like | A rate against one HS code line | A currency amount owed on one declaration |
| Where a shipper meets it | Looked up ahead of time, to estimate landed cost | Billed once customs reviews the actual shipment |
The other job the word “tariff” does
UPS's glossary entry for tariff does not stop at customs. It adds a second sense in the same line: the word can also describe the transportation rates a carrier files for its own service, with no government and no border involved anywhere in it.
The freight guides on this site use exactly that second sense — a rules tariff or a rate tariff published by a trucking line, the kind quoted with an item number on our LTL transit-time guide and elsewhere in the freight section. A “tariff item” on a bill of lading and a “tariff rate” on a customs declaration share a name and nothing underneath it. Reading one as the other is the easiest way to misread either document.
Where these definitions come from
- UPS, Glossary of Terms — the Duty and Tariff entries quoted above, including tariff's second, non-customs sense. No revision date shown on the page. Read 2026-08-28.
- DHL, What Is Import Duty? Import Taxes & Shipping Duty Explained — the definition of import duty and the five factors that set its amount. Published June 5, 2025, read 2026-08-28.
Both are glossary and explainer pages published by carriers, not a government tariff schedule. A specific product's actual rate is set by the importing country and looked up against that country's own published schedule, not against either page cited here.
Common questions
What is the difference between import duty and a tariff?
A tariff is the rate a government sets on a category of goods. A duty is the dollar amount one specific shipment owes once that rate is applied to its declared value. UPS's own glossary defines the two almost identically, duty as a government tax on imported goods and tariff as a government tax on goods entering or exiting the country, which is exactly why the words get used as synonyms even though only one of them is ever a number on an invoice.
Is a tariff the same thing as a customs duty?
Not quite. DHL's explainer treats duty as the umbrella tax collected by customs authorities on goods sold across borders, and names tariffs as one of the mechanisms that produce it, alongside excise duties and other border charges. A tariff without a shipment attached to it is a rate on a published schedule. A duty is that rate turned into a charge on one real shipment.
How does a tariff rate turn into a duty amount?
By being applied to a shipment's declared value once that shipment is classified. DHL names the inputs directly: the value of the goods including insurance and shipping, the goods' description, the country of origin, the destination country's tariff rate, and the goods' HS code. Two shipments under the same tariff rate can still owe different duty, because the rate is fixed and the value underneath it is not.
Does the word tariff ever mean something other than an import tax?
Yes. The UPS glossary entry for tariff adds a second sense on the same line: the transportation rates a carrier files for its own service, with no government and no border involved. A tariff item on a freight bill of lading and a tariff rate on a customs declaration share a name and nothing else.
Who actually sets a tariff rate?
The importing country's government, not a carrier. Each country publishes and revises its tariff schedule on its own timeline, and a shipment's HS code is what tells customs which line of that schedule applies. Carriers collect and remit the duty that results; none of them sets the rate it is based on.