How to Calculate Amazon FBA Fees: Complete Guide (2026)

Accurate fee calculation is the difference between profitable products and money-losing mistakes. A product that looks profitable at a glance can actually lose money once you account for Amazon's fee structure.

This guide walks through the exact process to calculate FBA fees, with real examples and the formulas you need.

Why Accurate Calculation Matters

Consider this product:

• Your cost: $12.00
• Amazon selling price: $29.99
• Apparent profit: $17.99

Looks great, right? Let's see what happens with actual fee calculation:

Still profitable—but 60% less than the apparent profit. And we haven't accounted for returns, advertising, or price fluctuations.

The Complete FBA Fee Formula

Net Profit = Selling Price - Product Cost - Referral Fee - FBA Fee
             - Prep Cost - Inbound Shipping - Storage Fee - Other Costs

Let's calculate each component.

Step 1: Determine Product Size Tier

FBA fees are based on product size tier. You need accurate dimensions and weight.

Measuring Your Product

Measure the packaged product (how it will be shipped to customers):

• Length: Longest side
• Width: Second longest side
• Height: Shortest side
• Weight: Actual shipping weight

Size Tier Thresholds (2026)

Important: If ANY dimension exceeds the tier limits, the product moves to the next tier up. A 16" item is Large Standard even if it weighs 8 oz.

Dimensional Weight

For large standard and above, Amazon may use dimensional weight instead of actual weight:

Dimensional Weight (lb) = (Length x Width x Height) / 139

Amazon charges based on the greater of actual weight or dimensional weight.

Example:

• Product: 16" x 12" x 6" box, actual weight 2 lb
• Dimensional weight: (16 x 12 x 6) / 139 = 8.3 lb
• FBA fee based on: 8.3 lb (dimensional is higher)

Step 2: Look Up the FBA Fulfillment Fee

Once you know the size tier and shipping weight, find the corresponding fee.

Small Standard Size Fees (2026)

Large Standard Size Fees (2026)

Large Bulky Fees

Base fee: $9.61

Additional: $0.38 per pound above 1 lb

Example: 15 lb large bulky item

• Fee: $9.61 + ($0.38 x 14) = $9.61 + $5.32 = $14.93

Extra-Large Fees

Step 3: Calculate Referral Fee

The referral fee is Amazon's commission on every sale.

Formula

Referral Fee = Selling Price x Category Rate

Common Category Rates

Minimum Referral Fee

Most categories have a $0.30 minimum. For very low-priced items:

Example: $1.99 item in 15% category

• Calculated fee: $1.99 x 0.15 = $0.30
• Since $0.30 = minimum, fee is $0.30

For a $1.50 item:

• Calculated fee: $1.50 x 0.15 = $0.23
• Since $0.23 < $0.30 minimum, fee is $0.30

Step 4: Estimate Storage Fees

Storage fees apply to all inventory sitting in Amazon's warehouses.

Monthly Storage Rates

Storage Fee Formula

Monthly Storage = Volume (cu ft) x Rate x Average Units Stored

Calculating Cubic Feet

Cubic Feet = (Length x Width x Height in inches) / 1728

Example:

• Product: 10" x 8" x 4"
• Cubic feet: (10 x 8 x 4) / 1728 = 0.185 cu ft
• 50 units stored in March: 0.185 x $0.78 x 50 = $7.22/month

Per-Unit Storage Allocation

To factor storage into per-unit profitability:

Storage per Unit = (Cubic feet x Monthly rate) / Monthly turnover

Example: If you sell 50 units/month and store 50 units:

• Storage per unit: $7.22 / 50 = $0.14/unit

Fast-turning inventory has minimal storage cost impact. Slow-moving inventory kills profits.

Aged Inventory Surcharges

Don't forget surcharges for inventory over 180 days:

Step 5: Add Prep and Inbound Costs

Prep Costs

If you prep yourself:

• FNSKU labels: ~$0.05-0.10/unit
• Poly bags: ~$0.05-0.15/unit
• Bubble wrap: ~$0.15-0.30/unit
• Boxes/packaging: ~$0.10-0.50/unit

If using a prep center:

• Basic labeling: $0.15-0.30/unit
• Full FBA prep: $0.75-2.00/unit

See our FBA Prep Center Database for pricing details.

Inbound Shipping

Cost to ship inventory to Amazon:

For calculation purposes, estimate $0.50-1.00/unit for most standard-size products.

Putting It All Together: Complete Examples

Example 1: Small Standard Item

Product: Phone case

• Dimensions: 6" x 4" x 0.5"
• Weight: 3 oz
• Your cost: $3.00
• Selling price: $12.99
• Category: Cell phone accessories (15%)

Calculation:

Example 2: Large Standard Item

Product: Bluetooth speaker

• Dimensions: 8" x 6" x 4"
• Weight: 1.8 lb
• Your cost: $18.00
• Selling price: $44.99
• Category: Electronics (8%)

Calculation:

Example 3: Large Bulky Item

Product: Outdoor furniture cushion set

• Dimensions: 24" x 20" x 12"
• Weight: 8 lb
• Your cost: $35.00
• Selling price: $89.99
• Category: Patio & Garden (15%)

Calculation:

Note: Large bulky items can still be profitable, but storage costs and FBA fees eat more margin.

Why Manual Calculation Doesn't Scale

The examples above take 5-10 minutes each to calculate properly. Now imagine:

• A supplier sends you a price list with 3,000 products
• You need to identify the profitable ones
• Each requires dimension lookup, fee calculation, profit analysis

At 5 minutes per product: 250 hours of work for one supplier list.

This is why Amazon wholesale sellers use bulk analysis tools.

Tools for Fee Calculation

Amazon Revenue Calculator (Free)

Amazon's official tool for single-product calculations.

How to use:

1. Go to Seller Central → Revenue Calculator
2. Enter ASIN or product details
3. Input your cost
4. View fee breakdown and profit

Limitations:

• One product at a time
• Requires manual input
• No bulk capability

Best for: Spot-checking individual products

RocketSource (Bulk Analysis)

Built for wholesale sellers processing supplier price lists.

How it works:

1. Upload CSV with product identifiers (UPC, ASIN) and costs
2. System automatically:
   • Converts UPCs to ASINs
   • Looks up current Amazon prices
   • Calculates all fees
   • Computes profit/ROI
3. Download results with profitability for every product

Best for: Analyzing supplier lists with hundreds or thousands of products

Free tier: 50,000 UPC conversions per week

When to Use Which

Common Calculation Mistakes

1. Forgetting Dimensional Weight

A light but bulky product may have higher fees than expected because dimensional weight exceeds actual weight.

2. Wrong Category Rate

Double-check your product's category. A product you think is "Electronics" (8%) might actually be classified as "Everything Else" (15%).

3. Ignoring Prep and Inbound

These "small" costs add up:

• 100 units x $1.00 prep = $100
• 100 units x $0.50 inbound = $50
• $150 that needs to come from profit

4. Underestimating Storage

Fast sellers: minimal impact

Slow sellers: storage can exceed product cost over time

5. Not Accounting for Returns

Budget 3-8% of sales for returns depending on category. Returned units may be unsellable.

6. Using Old Fee Data

Amazon updates fees annually (sometimes more). Use current year rates.

Profitability Thresholds

Minimum Targets

When to Pass on a Product

• Net margin < 10%: Too little room for error
• ROI < 20%: Capital better deployed elsewhere
• Profit < $2/unit: Not worth the handling

Building in Margin for Error

Real-world factors that erode calculated profit:

• Price drops from competition
• Returns
• Storage fees if slower than expected
• Advertising costs

Build 5-10% buffer into your minimum targets.

Frequently Asked Questions

How often do FBA fees change?

Amazon typically updates FBA fees annually in February. Storage fee adjustments and other changes may happen throughout the year. Always verify against current fee schedules.

Do fees differ for new vs. established sellers?

No. Amazon's fee structure is the same for all sellers. Established sellers may have negotiated better rates with prep centers or shipping carriers, but Amazon fees are identical.

How do I handle products with variable dimensions?

For products sold in different configurations (multipacks, bundles), calculate fees for each variation separately. The smallest profitable configuration may not scale to larger bundles.

Should I include advertising in my calculations?

Yes, if you plan to advertise. Many products require PPC to maintain visibility. Budget 10-20% of revenue for advertising costs in competitive categories.

What about FBA fee discounts?

Amazon occasionally offers fee reductions for new products, specific categories, or promotional periods. Don't count on these for baseline profitability—treat them as bonus margin.

Quick Reference Formulas

Referral Fee = Selling Price x Category Rate

FBA Fee = Look up by Size Tier + Weight

Storage Fee = Cubic Feet x Monthly Rate x Units

Dimensional Weight = (L x W x H) / 139

Cubic Feet = (L x W x H) / 1728

Net Profit = Price - Cost - Referral - FBA - Prep - Inbound - Storage

ROI = Net Profit / Total Cost x 100

Margin = Net Profit / Selling Price x 100

Next Steps

• Amazon Seller Fees Breakdown — Complete fee reference
• Amazon Wholesale Guide — Build profitable wholesale business
• Free UPC Converter — Start analyzing products
• FBA Prep Database — Find prep services and pricing

Want to calculate fees automatically for thousands of products?

Start Free with RocketSource →

Upload supplier price lists, get instant profitability analysis with all fees calculated automatically—50,000 free conversions per week, no credit card required.