A landed cost calculator that pulls in customs duties does the math automatically once you feed it the HTS code and country of origin for each SKU — it applies the correct duty rate to your product cost and rolls the result into landed cost per unit. The catch: duty is one line item among several. Section 301 tariffs, the Merchandise Processing Fee, and the Harbor Maintenance Fee stack on top for a huge share of imports, and a calculator that only tracks a single "duty %" field will quietly undercount your true cost.
- A landed cost calculator factors in customs duties by applying the HTS-based duty rate to product cost per SKU.
- Section 301 tariffs add 7.5% to 25% on top of standard duty for many China-origin goods in 2026.
- The Merchandise Processing Fee runs 0.3464% of shipment value, with a per-entry floor and ceiling set by CBP.
- Spreadsheets can track duty rates, but they don't auto-update HTS classifications or catch missed Section 301 entries.
- SupplyAutomate pulls duty, freight, and fees from your invoices and POs into one landed cost calculator, no manual entry.
Why this matters
Most sellers who ask whether a landed cost calculator handles customs duties already got burned once — a duty rate changed, a broker invoice showed a fee nobody budgeted for, or a "landed cost" spreadsheet turned out to only include freight. Customs duties aren't optional to model in 2026: with Section 301 tariffs still active on large categories of Chinese-origin goods, the gap between "unit cost" and "true landed cost" can be the difference between a 30% margin product and a break-even one.
The question isn't just whether a calculator can hold a duty percentage. It's whether it keeps that percentage current, applies it per HTS code instead of per shipment, and layers in the CBP fees that ride along with every formal entry.
Can a landed cost calculator factor in customs duties?
Yes, and here's what the calculation actually looks like when it's done right. A landed cost calculator that handles duty properly builds the figure from the entry documentation — your commercial invoice, packing list, and customs entry summary — rather than a single manual field.
| Cost component | Where it comes from | Included in most basic tools? |
|---|---|---|
| Product cost (FOB) | Supplier invoice | Yes |
| Ocean/air freight | Freight forwarder invoice | Yes |
| Customs duty (HTS-based %) | Customs entry summary (CBP Form 7501) | Sometimes — often manual |
| Section 301 tariff | Customs entry summary | Rarely automated |
| Merchandise Processing Fee (0.3464% of value) | Customs entry summary | Rarely automated |
| Harbor Maintenance Fee (0.125% of value) | Customs entry summary | Rarely automated |
| Insurance | Freight forwarder or broker invoice | Sometimes |
| Broker fees | Customs broker invoice | Rarely |
The complete landed cost breakdown guide walks through each line with worked examples, but the short version: if your calculator stops at "product + freight," you're not calculating landed cost, you're calculating half of it.
Standard customs duty: 0% to 37.5%+ depending on HTS code
Duty rates aren't a flat percentage across your catalog. They're set per HTS classification, and the range is wide — plenty of goods clear at 0% duty, while footwear, apparel, and certain textiles can run north of 30%. A landed cost calculator that stores one duty rate per supplier instead of per SKU will misprice every product that doesn't share the same classification.
Section 301 tariffs: an added 7.5% to 25% on many China-origin goods
Section 301 tariffs sit on top of standard duty for products on the affected lists, and they're specific to country of origin — not country of shipment. A calculator has to know the actual manufacturing origin, not just where the pallet left from, or it will miss this line entirely. For sellers importing from China, this is usually the single largest gap between estimated and actual landed cost.
Merchandise Processing Fee: 0.3464% of shipment value
MPF is an ad valorem fee CBP charges on formal entries, with a minimum and maximum per entry set by regulation. It's small on a per-unit basis but adds up across a year of shipments, and almost no spreadsheet template accounts for it by default.
Why duty totals vary from shipment to shipment
- HTS classification accuracy — the wrong 10-digit code can shift duty by double digits on the same physical product
- Country of origin — determines whether Section 301 or other origin-specific tariffs apply, independent of where goods ship from
- Trade agreement eligibility — USMCA and other preference programs can zero out duty on qualifying goods
- Declared value — duty and MPF are both calculated as a percentage of the value declared on the entry
- De minimis eligibility — shipments have historically qualified for duty-free treatment under Section 321 at low declared values, though current thresholds and enforcement should be confirmed against active CBP guidance before relying on them for 2026 planning
- Freight terms — FOB vs. CIF pricing changes what value duty is calculated against
This is also where spreadsheets, Cin7, and Inventory Planner diverge in what they actually do. A spreadsheet can hold a duty rate column, but someone has to update it by hand every time a classification or tariff list changes — fine for a five-SKU catalog, painful past fifty. Cin7 and Inventory Planner both handle inventory forecasting well, but neither was built to ingest a customs entry summary and reconcile it against a purchase order automatically; duty usually still gets entered manually or estimated at a flat rate. Tools built specifically as a landed cost calculator close that gap, and the difference matters most for sellers running more than a handful of SKUs across multiple HTS codes.
SupplyAutomate reads the invoice and PO documents you already have — supplier invoice, freight bill, customs entry summary — and calculates landed cost per unit without manual data entry, pulling duty and fees straight from the paperwork instead of a static assumption. That's a different approach from tools that ask you to key in a duty percentage once and forget it.
Does landed cost include customs duties and freight?
Yes, landed cost includes customs duties and freight by definition — it's the total cost to get a unit onto your shelf, not just the price you paid the supplier. Leaving either one out means every margin calculation downstream of it is wrong, sometimes by 20 points or more once Section 301 tariffs are in play.
What's the difference between a customs duty and a tariff?
A customs duty is the standard tax applied under a product's HTS classification, while a tariff (like Section 301) is an additional, often trade-policy-driven charge layered on top for specific origins or categories. Both hit the same customs entry summary, but they're calculated and applied under separate legal authorities — a calculator needs to track them as distinct line items, not one blended rate.
Can I calculate landed cost without knowing the HTS code?
No, not accurately — the HTS code is what determines the duty rate, so skipping it means guessing at the single largest variable cost component after freight. Sellers who don't have HTS codes handy usually get them from their customs broker's entry paperwork or their supplier's commercial invoice, both of which a landed cost calculator can pull data from directly.
FAQ
Does a landed cost calculator include customs duties automatically?
A landed cost calculator includes customs duties automatically when it's fed the HTS code and country of origin per SKU; without that data it defaults to a flat estimate that misses per-product variation.
What percentage is a typical customs duty rate in 2026?
Customs duty rates in 2026 run from 0% to 37.5% or higher depending on the HTS classification, with no single average that applies across product categories.
How much do Section 301 tariffs add to landed cost?
Section 301 tariffs add 7.5% to 25% on top of standard duty for many China-origin goods, applied based on country of origin rather than shipping origin.
Is the Merchandise Processing Fee included in landed cost?
The Merchandise Processing Fee, calculated at 0.3464% of shipment value, should be included in landed cost since it's charged on nearly every formal customs entry.
Can Excel calculate landed cost with customs duties?
Excel can calculate landed cost with customs duties if someone manually updates duty rates, HTS codes, and fee percentages every time they change, which becomes unmanageable past a small SKU count.
Do Cin7 and Inventory Planner calculate customs duties?
Cin7 and Inventory Planner focus on inventory forecasting and don't natively pull customs entry data, so duty is usually entered manually or estimated at a flat rate in both platforms.
Do I still need a customs broker if my software calculates duties?
Yes, a customs broker still files the actual entry with CBP; a landed cost calculator estimates and tracks the cost impact but doesn't replace the broker's compliance role.
What documents does a landed cost calculator need to factor in duties?
A landed cost calculator needs the commercial invoice, freight bill, and customs entry summary (CBP Form 7501) to factor in duties, Section 301 tariffs, and CBP fees accurately.
One last thing
The fee sellers miss most often isn't duty — it's the Harbor Maintenance Fee, a separate 0.125% ad valorem charge on ocean freight entries that almost never shows up in a spreadsheet template. It's small per shipment, but across a year of container imports it's real margin leaking out of a number that most sellers assume is "just duty and freight." Pull your last customs entry summary and check whether your current landed cost figure actually accounts for it.
See your true landed cost per SKU
Upload the invoices and POs you already have — no manual duty entry.