
FBA vs FBM Calculator: The Break-Even Formula, Worked Step by Step (2026)
An FBA vs FBM calculator only has to answer one question: is your all-in cost to ship one unit yourself lower than Amazon’s all-in cost to ship it for you? The break-even point is the FBM postage label at which the two sides tie — break-even postage = FBA fulfillment fee + FBA storage per unit + inbound placement and prep per unit − your own packing, labor, and storage per unit. If your real label costs less than that number, FBM keeps more margin on that SKU; if it costs more, FBA does. Then one second check decides whether the Prime badge on FBA sells enough extra units to overturn a small FBM saving. ...










