Total Cost of Ownership research shows buyers systematically price at the invoice and overlook hidden costs — how to compute true landed cost to your Thai warehouse: CIF, duty, the VAT that compounds on top of duty, Thai-side charges, and allocating shipment costs per unit so the satang add up exactly.
This article is internal cost-planning guidance, not customs, tax, or legal advice — the amounts actually payable always follow the import declaration and official receipts.
How a "cheap" import quietly loses money
Order an item from China at 85 yuan, rate roughly 5 baht, so cost 425 baht — price it at 600 and the margin looks fine. That is how most small importers think, and it is how plenty of "cheap" goods end up sold below true cost without the owner ever knowing.
Because by the time that item reaches your warehouse it has been collecting costs all the way: sea freight, insurance, duty at your tariff line, VAT computed on a base that already includes the duty, D/O fees, port handling, customs clearance, trucking — and all of it has to be allocated back down to a per-unit figure before a price is set.
This is not a beginners-only problem. Lisa Ellram's foundational Total Cost of Ownership research (1993, 1995) found that even professional purchasing organisations systematically buy on the invoice price and overlook the hidden costs — the invoice is easy to see, while the rest is scattered across many small bills, currencies, and points in time.
The standard customs arithmetic: costs stack in layers
Import costs do not add up flat — they compound in layers:
| Layer | Formula | Where people slip |
|---|---|---|
| CIF | goods (FOB) + freight + insurance | converting at a stale rate, not the day you transfer |
| Import duty | tariff rate × CIF (THB) | the rate depends on each product's HS code |
| Import VAT | VAT rate × (CIF + duty + excise) | computing off CIF alone — wrong; the base includes duty |
| Thai-side | D/O + port + clearance + trucking | scattered across bills, never totalled |
The layer missed most often is VAT compounding on duty: the legal base for import VAT is CIF plus import duty plus excise (if any) — a shipment with 10% duty carries proportionally more VAT per unit. Anyone multiplying 7% off the goods value alone always under-costs.
The other switch worth a full 7% is your VAT registration status: a registered business credits import VAT back as input tax — cash at clearance, but not a true cost. A non-registered business bears it entirely. A calculator that never asks is wrong for someone.
Allocating shipment costs: the satang must come out exact
Freight, duty and Thai-side charges are shipment-level costs — but pricing needs per-unit costs, so allocation is the heart of landed costing:
- By value — the accounting standard; expensive goods absorb more; right for general cargo
- By weight/volume — right when transport dominates and items differ wildly (a box of bolts and one machine should not split evenly)
- By piece count — simplest, fine when the bill is homogeneous
Where amateur spreadsheets break is rounding: round each line and the total no longer equals the pool — 37 satang vanish with no explanation. The correct rule is that one designated line absorbs the remainder, so every allocation sums back to the shipment pool to the satang — auditable, nothing leaks.
The exchange rate is a risk most SMEs carry without choosing to
Between ordering and actually transferring, the rate can move several percent — and surveyed SME behaviour (EFIGE data, cited in Duke 2022) suggests only about one small firm in ten hedges currency risk with real financial instruments. The rest simply carry the exposure.
For a small importer the practical answer is not hedging but knowing in advance what a unit will cost if the rate runs: the FX-linked part of the cost (CIF, duty, and VAT on CIF) moves with the rate, while Thai-side charges are fixed baht. A pre-computed "per unit at ±5% / ±10%" table lets you price against the risky side on quotation day — not discover it on payment day.
The lowest price that still meets your margin
Landed cost ends in one number: the lowest price that still hits target margin — true landed cost per unit ÷ (1 − target GM), where GM is a share of the selling price, not a markup on cost (cost 75 at GM 25% → sell 100, not 93.75), rounded UP to your pricing step. Up only — rounding down is choosing to miss your own target.
The tool that does all of this in one file
Landed Cost Per Unit — Import Costing (Thailand Edition) is an Excel file built from everything in this article: enter one shipment header plus its SKU lines and get CIF → duty → cascaded VAT → Thai-side charges → per-unit allocation (sums back to the pool exactly, under every method) → the minimum price at your target GM → a rate-stress table at ±5%/±10%, with a VAT-registration switch, an FTA (Form D/E) switch, and a 30-check live self-test sheet you can open and watch compute. One purchase includes both the Thai edition and the English (Thailand) edition.
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Frequently Asked Questions
1What is landed cost and how is it different from the purchase price?
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2What is the base for Thai import VAT?
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3Does VAT registration change my import cost?
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4How should shipment-level costs like freight and broker fees be allocated across SKUs?
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