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FBA Size Tier & Dimensional Weight Calculator

Find out which Amazon size tier your product falls into, what you are billed on, and whether a smaller box would cut your FBA fee.

Updated October 2026 · US marketplace

Your size tier

Enter the packaged size and weight.

Size tier—

FBA fee (with 3.5% surcharge)—

Sides (longest first)—
Length + girth—
Unit weight—
Dimensional weight—
Billable weight—
Base FBA fee (non-peak)—

Next: see your full profit with this fee →

2026 size tiers

Limits for each tier

Tier	Longest × median × shortest	Max weight	Charged on
Small standard	15 × 12 × 0.75 in	16 oz	Unit weight
Large standard	18 × 14 × 8 in	20 lb	Greater of unit or dimensional weight
Small bulky	37 × 28 × 20 in, length + girth ≤ 130 in	50 lb	Greater of unit or dimensional weight
Large bulky	59 × 33 × 33 in, length + girth ≤ 130 in	50 lb	Greater of unit or dimensional weight
Extra-large	Above large bulky	—	Greater of unit or dimensional weight

Fees use Amazon's US rate card effective 15 January 2026 (non-peak, non-apparel). Holiday peak fees apply 15 October to 14 January. Confirm your tier in Seller Central's Fee Preview. More in our size tiers guide.

Frequently asked questions

What are the Amazon FBA size tiers in 2026?

Small standard (up to 15 × 12 × 0.75 in and 16 oz), large standard (up to 18 × 14 × 8 in and 20 lb), small bulky, large bulky and extra-large. The tier sets which fulfillment fee table applies.

How is dimensional weight calculated?

Length × width × height in inches, divided by 139, gives dimensional weight in pounds. For bulky items, width and height are counted as at least 2 inches.

What is billable weight?

Small standard items are charged on unit weight. Large standard and bigger items are charged on the greater of unit weight and dimensional weight, so a light but large box can cost more than its real weight suggests.

How can I lower my FBA fee?

Shrink the packaging. Dropping from large standard to small standard, or from bulky to large standard, often saves more than any other change. Even a smaller box within the same tier can lower billable weight.