Landed Cost & Duty Estimator: Know the True Per-Unit Cost Before the Broker Bill Lands
Turn PO lines, an HS-to-duty-rate table, freight, insurance, and fees into a true landed cost per unit — duty applied by HS code and country, freight allocated your way — with the import manager reviewing and approving the estimate before it ever feeds pricing or PO approval.
A logged-in tool where you enter PO lines and values, apply the right duty rate by HS code and country of origin, allocate freight and insurance across the lines by your chosen method, see landed cost per unit, have the import manager review and approve, and export a fully costed PO.
Before you start
- A Supabase account (free)
- A Vercel account (free)
- A Resend account (free)
- Your PO lines with values (CSV or Google Sheet)
- An HS-code-to-duty-rate table you can export (CSV)
- Your typical freight, insurance, and brokerage fee figures
- Claude Code or any AI coding agent
The problem this kills
The price on the supplier's invoice is never what the goods actually cost you. By the time the container clears, you've paid duty at a rate that depends on the HS code and where the goods were made, ocean or air freight, insurance, brokerage, and a handful of fees nobody warned you about. The buyer who locked in a margin on the invoice price discovers it three weeks later — when the broker's bill arrives and the "good deal" has quietly turned thin.
Most teams estimate landed cost in a spreadsheet that one person built and only one person understands. The duty rates are typed in from memory or a stale lookup. Freight gets smeared across lines "about evenly" instead of by weight or value. The HS codes don't match what the broker actually used. And there's no record of who approved the number that pricing then trusted. When the real bill comes in different, nobody can reconstruct why.
Landed cost is the number your pricing and your PO approvals quietly depend on. It deserves to be a real, governed tool — not a workbook held together by one person's memory of last year's duty rates.
What you'll build
A simple internal web app for purchasing, import, and pricing. You enter (or import) your PO lines — SKU, description, quantity, unit value, HS code, and country of origin. The tool looks each line up against your maintained duty-rate table (keyed by HS code and country, because the same product can be duty-free from one country and dutiable from another), applies the duty, then allocates freight and insurance across the lines by the method you pick — by value, by weight, by volume, or by units. It adds your brokerage and handling fees, and lands on a true cost per unit for every line.
The import manager reviews the estimate — the HS-to-rate matches, the freight split, any line that looks off — and approves it before that number is allowed to feed pricing or a PO approval. Nothing downstream trusts a landed cost until a person has signed off. You export a clean, fully costed PO in the exact columns your ERP or pricing sheet expects.
What's inside the Implementation Plan
The downloadable plan is a step-by-step file you paste into an AI coding agent. It opens by interviewing you about your business — how you import today, what your PO lines actually look like and what you call each field, how your HS codes and duty rates are structured, which freight allocation method matches how you really think about cost, your fee types, and the messy exceptions (mixed-origin POs, free-trade-agreement preference rates, anti-dumping duties, partial shipments). It reflects a short tailored spec back to you and waits for your thumbs-up before it builds anything — so the tool fits how you import, not a generic template.
From there it walks the agent through the data model, the duty-rate table, the PO-line import, the duty lookup, the freight/insurance allocation engine, the per-unit landed cost calculation, the import-manager approval gate, and the costed-PO export. Every step ends with a ready-to-copy prompt. There's a full "No API yet?" path that uses Google Sheet / CSV imports and produces a clean CSV export — so you can build and run the whole thing this weekend with no connection to your ERP or broker's system.
The governance it includes (this is the point)
Landed cost feeds money decisions, so the controls aren't optional. The plan builds in login so only your team can use it, row-level security so you only ever see your own organization's POs and rates, a complete audit trail of who changed a duty rate, who edited an allocation, and who approved which estimate, a hard human-approval gate so no landed-cost number reaches pricing or PO approval until the import manager signs off, and duplicate guards keyed on the PO line so the same line can't be costed and counted twice on re-import.
Who it's for
Purchasing and procurement, import and customs managers, and pricing or margin analysts — anyone who has ever been surprised by a broker bill or set a price off an invoice cost that turned out to be wrong. If you can explain how your POs are shaped and where your duty rates come from, you can build this.
You've got this — start with the plan, paste the first prompt, and answer the interview. You'll have a true cost per unit on screen before the weekend's out.