What is dimensional weight and when does it apply?

Dimensional weight = (L × W × H) ÷ 139. Amazon charges the greater of actual weight or dimensional weight for Large Standard and all Oversize tiers. Small Standard products are only charged actual weight. For example: a box 12×10×8 inches weighing 1 lb has a dimensional weight of 6.9 lbs — you'd pay for 6.9 lbs.

How do FBA fees change during peak season?

Amazon charges a peak fulfillment surcharge from October 15 to January 14 each year. The surcharge adds approximately $0.20 for Small Standard items and up to $1.50 for Oversize items. Q4 also brings higher storage fees: $2.40/cubic foot vs. $0.75 off-peak. Factor this into your Q4 margin planning.

Are FBA fees the same for all product categories?

FBA fulfillment fees (the fee for picking, packing, and shipping your product) are the same across all standard categories and based purely on size and weight. Referral fees (Amazon's commission) vary by category. This calculator covers fulfillment fees only — see the Amazon FBA Calculator for a combined profit view including referral fees.

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Amazon FBA Fee Calculator

Enter your product dimensions and weight — estimate your FBA fulfillment fee and size tier

The Amazon FBA Fee Calculator estimates your fulfillment fee based on your product's dimensions and weight and the configured rates in this tool. Amazon charges different fees for each size tier — from Small Standard to Special Oversize — and the difference can dramatically impact your margins. Use this tool before ordering inventory to check whether your product lands in a cost-effective size tier, then verify final fees in Seller Central.

FBA Fee CalculatorLarge Standard (1–2 lb)

Length (inches)Width (inches)Height (inches)Weight (lbs)

Size tierLarge Standard (1–2 lb)

Dimensional weight1.01 lbs

Billable weight1.01 lbs

FBA Fulfillment Fee$5.06

Estimates based on standard FBA rates. Verify exact fees in Seller Central.

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Amazon's FBA fee structure is based on size tiers, which are determined by your product's dimensions and weight. Here's how to get a practical fee estimate based on configured rates.

Step 1 — Measure the packaged product

Measure the length, width, and height of your product as it will be packaged for FBA — including any inserts, poly bag, or box. Amazon measures the longest side, median side, and shortest side. The dimensions of the packaged (not unboxed) product determine your size tier.

Step 2 — Weigh the packaged product

Weigh the complete package including packaging materials. Use actual weight. Amazon will also calculate dimensional weight (L×W×H÷139) and charge whichever is greater for large packages. For products under 1 lb that are large in size, dimensional weight often applies.

Step 3 — Read your size tier

The calculator automatically assigns your size tier: Small Standard (longest side ≤15", weight ≤0.25 lb), Large Standard (longest side ≤18", weight ≤20 lb), Small Oversize (longest side ≤60"), Medium Oversize (longest side ≤108"), Large Oversize, or Special Oversize. Each tier has a different base fulfillment fee.

Step 4 — Check if you can optimize

If you're near a size tier boundary, consider whether packaging adjustments could move you to a lower-cost tier. For example, reducing box height by 0.5 inches to stay under 18" can save $1–3 per unit in fulfillment fees. At 500 units per month, that's $500–1,500 in monthly savings.

💡 Pro tips

•Always measure the packaged product, not the bare item
•For products near size tier boundaries, Amazon may re-measure and charge the higher tier
•Dimensional weight often applies for lightweight but bulky products — always check both
•Q4 peak fulfillment fees (Oct 15–Jan 14) add $0.20–$0.40 per unit across most tiers

Frequently Asked Questions

Amazon's FBA size tiers are: Small Standard (≤15"×12"×0.75", ≤16 oz), Large Standard (≤18"×14"×8", ≤20 lb), Small Oversize (≤60"×30", ≤70 lb), Medium Oversize (≤108", ≤150 lb), Large Oversize (≤108", ≤150 lb with girth), Special Oversize (anything larger). Base fees range from $3.06 for Small Standard to $200+ for Special Oversize.