What changed, what it costs, and what to do about it. Every post carries the date it was written and the date it was last checked, because on this subject those are different things.
On 12 July 2026 USPS moved from a 166 divisor to 139 and started rounding fractional inches up. Here is what it does to a real parcel, and how to check whether a tool has caught up.
Read it →The US suspended duty-free de minimis for all countries in August 2025 and made it permanent in 2026. Worked examples of what that does to a $12 landed cost, and what to change.
Read it →Three price bands in January, a 3.5% surcharge in April, a Digital Services Fee expansion in March. Worked per-unit numbers, and why most FBA calculators are understating your fees.
Read it →Break-even ACOS comes from your fee stack, not your campaign report. How to work it out, turn it into a bid ceiling, and why chasing a low ACOS can cost you money.
Read it →Dividing pallet volume by carton volume overstates what fits, often by twenty percent. How real two-block packing works, and what it changes about your freight quote.
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