FBA Profit Calc

Our Methodology

Transparency is core to our mission. This page documents every formula, data source, and assumption used in our calculators so you can verify our math independently.

Data Sources

All fee data in our calculators is sourced directly from Amazon Seller Central's official documentation. We do not use third-party estimates or scraped data.

Calculation Formulas

Referral Fee

Referral Fee = MAX(Selling Price × Category Rate, Minimum Fee)

Category rates range from 8% to 45%. The minimum fee is $0.30 for most categories. Amazon charges whichever is greater.

FBA Fulfillment Fee

Fulfillment Fee = Lookup(Size Tier, Shipping Weight)

Size tier is determined by product dimensions and weight. The fulfillment fee is a fixed amount per unit based on the tier and weight bracket.

Size Tier Classification

Small Standard: ≤16 oz, ≤15" × 12" × 0.75"

Large Standard: ≤20 lbs, ≤18" × 14" × 8"

Small Oversize: ≤70 lbs, ≤60" × 30", L+G ≤130"

Medium Oversize: ≤150 lbs, ≤108", L+G ≤130"

Large Oversize: ≤150 lbs, ≤108", L+G ≤165"

Special Oversize: Exceeds all above

Dimensions are sorted longest → median → shortest. Girth = 2 × (median + shortest). L+G = longest + girth.

Monthly Storage Fee

Storage Fee = (L × W × H ÷ 1728) × Rate per cubic foot

Standard-size: $0.87/cu ft (Jan–Sep), $2.40/cu ft (Oct–Dec). Oversize: $0.56/cu ft (Jan–Sep), $1.40/cu ft (Oct–Dec).

Fuel & Logistics Surcharge

Fuel Surcharge = Fulfillment Fee × 3.5%

Applied to all FBA fulfillment fees as of April 2026.

Net Profit

Net Profit = Revenue − COGS − All Amazon Fees − Shipping − Ads − Returns − Prep − Misc

Profit margin = Net Profit ÷ Revenue × 100. ROI = Net Profit ÷ COGS × 100.

Update Process

Amazon typically updates its fee schedules in January and mid-year. When changes are announced, we follow this process:

  1. Monitor Amazon Seller Central announcements and fee change notifications.
  2. Cross-reference new fee schedules against multiple official Amazon help pages.
  3. Update all calculator data within 48 hours of confirmed changes.
  4. Run automated tests to verify calculations against known examples.
  5. Document all changes in our changelog.

Limitations & Disclaimers

Our calculators provide estimates based on publicly available Amazon fee schedules. Actual fees may differ due to: individual seller agreements, promotional pricing, Amazon policy changes not yet reflected in our data, or product-specific attributes. We recommend using our tools for planning and product research, and cross-referencing with Amazon's Revenue Calculator before making final sourcing decisions. This tool is not affiliated with Amazon.