Amazon Seller Taxes and Repricing: Are You Setting Your Price Floor Wrong?

Last updated: September 2026

Most Amazon sellers calculate their repricing floor from three inputs: sourcing cost, FBA fees, and referral fee. They set a target margin and produce a minimum price. The floor looks accurate. In practice, it protects gross margin, not net profitability after tax.

Income tax on business profits is a real cost of each sale. If the effective income tax rate is 25% and the floor is set for a 10% margin, the actual after-tax return on each floor-price sale is 7.5%. A seller who wants to protect a 10% after-tax return needs to configure a higher floor, specifically, one that targets a 13.3% pre-tax margin at 25% tax rate.

US sales tax, by contrast, does not require a floor adjustment for most Amazon sellers. Marketplace Facilitator laws mean Amazon collects and remits sales tax on behalf of US third-party sellers in all 50 states and Washington D.C., the seller's payout from Amazon is calculated on the selling price before tax. Sales tax does not come from seller margin.

This article covers what to include in the floor (income tax, VAT for UK/EU sellers) and what does not require floor adjustment (US sales tax under Marketplace Facilitator).

Consult a qualified tax professional before adjusting your floor calculation for tax obligations.

TL;DR: US sales tax is handled by Amazon under Marketplace Facilitator laws and does not affect the repricing floor. Income tax on business profits is a real cost that most sellers leave out of the floor formula. To protect a target after-tax margin, divide the desired after-tax margin by (1 minus the effective tax rate) to get the pre-tax margin target, then use this in the floor formula. For UK and EU VAT-registered sellers, the floor should be calculated on the ex-VAT price, not the VAT-inclusive listing price. Confirm all tax rates with a qualified professional before adjusting the configuration.

Amazon's Marketplace Facilitator rules: what Amazon handles for you

Under Marketplace Facilitator laws, Amazon collects and remits sales tax on behalf of third-party sellers in all 50 US states and Washington D.C. Amazon calculates the applicable tax, adds it to the buyer's order total, collects it from the buyer, and remits it directly to the relevant state tax authority. The seller's payout from Amazon does not include this tax.

This is a significant operational simplification for Amazon sellers. Before Marketplace Facilitator laws, third-party sellers were responsible for collecting and remitting sales tax in every state where they had nexus. The administrative overhead was substantial.

Under current Marketplace Facilitator rules:

• Amazon adds the applicable sales tax to the buyer's checkout total

• The buyer pays the selling price plus sales tax

• Amazon's payout to the seller is based on the selling price, not the selling price plus tax

• Amazon remits the collected tax to the relevant state authority

• The seller's 1099-K and settlement reports reflect revenues net of sales tax

What Marketplace Facilitator does not cover:

Amazon's Marketplace Facilitator responsibilities apply to sales through the Amazon marketplace. Sellers who also operate their own website, sell on eBay, or use other marketplaces that are not Marketplace Facilitators retain sales tax obligations on those channels.

Additionally, sellers with FBA inventory stored in a state warehouse have physical nexus in that state. This is relevant for state income tax filing requirements, not sales tax, since Amazon's Marketplace Facilitator coverage handles the sales tax collection in that state regardless of nexus type.

The Marketplace Facilitator conclusion for the floor formula:

Because Amazon collects sales tax from buyers and the seller's payout is based on the pre-tax selling price, US sales tax does not reduce the seller's margin and does not need to be included in the repricing floor calculation.

Income tax obligations sellers often miss in their floor calculation

Income tax on business profits is a cost that most repricing floor formulas do not include. The standard floor formula targets a gross margin percentage, it does not account for the income tax the seller will pay on that gross margin. As a result, the floor protects a gross return that is higher than the seller's actual after-tax return.

The gap:

A seller with a 15% gross margin target sets a floor that produces 15% on every unit sold at the floor price. If the effective income tax rate on business profits is 25%, the actual after-tax return per unit at the floor price is:

15% × (1 minus 0.25) = 11.25%

If the seller wanted to protect a 10% after-tax return, the floor is set too low: 11.25% after-tax exceeds the target, but the floor is higher than needed. If the seller wanted to protect a 15% after-tax return, the floor is set too low: the actual after-tax return at the current floor is only 11.25%.

Why income tax is commonly omitted:

Income tax is calculated on the annual tax return, not per transaction. Sellers who think about margin on a per-unit basis often do not convert their income tax obligation into a per-unit cost. The floor formula treats the gross margin as the endpoint, when for tax-liable businesses it is a waypoint before the tax liability is calculated.

Income tax inputs vary:

The effective income tax rate depends on business structure (sole proprietor, S-corporation, C-corporation, LLC), total income from all sources (for pass-through entities, additional income raises the marginal rate), and jurisdiction (US federal rate plus applicable state rate). Self-employed sellers also pay self-employment tax (15.3% on net self-employment income up to the Social Security wage base as of current US rates, reducing above it).

These figures are for illustrative purposes. Confirm your effective rate with a qualified tax professional.

The correct minimum price formula including tax obligations

The tax-adjusted floor formula adds the effective income tax rate as an input to produce a minimum price that protects the desired after-tax margin.

The standard floor formula (without income tax):

Floor = (COGS + prep cost + FBA fee) ÷ (1 minus referral fee rate minus target pre-tax margin rate)

The income-tax-adjusted formula:

Step 1: Calculate the required pre-tax margin from the desired after-tax margin. Required pre-tax margin = desired after-tax margin ÷ (1 minus effective income tax rate)

Step 2: Use the required pre-tax margin in the standard floor formula. Floor = (COGS + prep cost + FBA fee) ÷ (1 minus referral fee rate minus required pre-tax margin rate)

Worked example:

Inputs:

• COGS: $9.50

• Prep cost: $0.50

• FBA fee: $3.18

• Referral fee: 8%

• Desired after-tax margin: 10%

• Effective income tax rate: 25% (illustrative, confirm with a tax professional)

Step 1: Required pre-tax margin = 10% ÷ (1 minus 0.25) = 10% ÷ 0.75 = 13.33%

Step 2: Floor = ($9.50 + $0.50 + $3.18) ÷ (1 minus 0.08 minus 0.133) = $13.18 ÷ 0.787 = $16.75

Comparison, standard floor for 10% pre-tax margin (ignoring income tax): = $13.18 ÷ (1 minus 0.08 minus 0.10) = $13.18 ÷ 0.82 = $16.07

The tax-adjusted floor is $0.68 higher per unit. At 150 units per month, this represents $102 per month in after-tax margin that a seller would otherwise leave unprotected.

The ACoS integration:

For sellers running Sponsored Products, advertising costs also belong in the floor formula. The ACoS and repricing guide covers how to add the ACoS rate to the floor denominator. Income tax is calculated on the net margin after advertising costs, so the tax adjustment should apply to the after-advertising, after-cost target margin.

Book a Demo, configure a tax-adjusted repricing floor in Repricer.com with Net Margin Repricing that accounts for all costs including your income tax obligation.

US sales tax: how Marketplace Facilitator affects your liability

Amazon's Marketplace Facilitator status does not eliminate all US tax obligations for third-party sellers. It handles sales tax collection and remittance, it does not handle income tax, and it does not remove sellers' obligation to understand their nexus positions.

What sellers still need to manage:

FBA nexus: When Amazon stores FBA inventory in a state warehouse, the seller has physical nexus in that state. Amazon handles the sales tax collection as Marketplace Facilitator regardless of nexus type, so physical nexus from FBA inventory does not create additional sales tax obligations. It is relevant for state income tax filing requirements, sellers with FBA inventory across multiple states are likely required to file state income tax returns in those states. Confirm this with a tax professional.

Economic nexus: The 2018 South Dakota v. Wayfair Supreme Court decision established that states are permitted to require sales tax collection based on economic activity rather than physical presence. The most common threshold is $100,000 in annual sales to buyers in a state. Since Amazon handles sales tax collection in all US states as Marketplace Facilitator, economic nexus thresholds do not directly affect a seller's obligation to collect sales tax on Amazon sales. They remain relevant for sales on non-Marketplace-Facilitator channels.

Multi-platform sellers: Sellers who operate outside Amazon (own website, eBay where they ship from their own location, other platforms that are not Marketplace Facilitators) retain sales tax obligations on those channels based on nexus rules. The $100,000 threshold applies to total sales to a state across all channels, including non-Amazon ones.

Amazon tax reports: Amazon provides a Marketplace Tax Collection report in Seller Central showing taxes Amazon collected and remitted on the seller's behalf. This does not represent the seller's own tax liability, it is Amazon's remittance record. The seller's income tax obligations are calculated on net profit from the 1099-K and related reports.

VAT for UK and EU Amazon sellers: how to include it in your repricing floor

For Amazon sellers registered for VAT in the UK or EU, the listing price is the VAT-inclusive price. The seller's actual revenue is the ex-VAT amount, because the VAT portion is remitted to HMRC or the relevant national tax authority. The repricing floor must be calculated on the ex-VAT selling price, not the VAT-inclusive listing price.

This section applies to sellers who are VAT-registered in the UK or EU. Non-registered sellers and the application of these rules to specific countries vary significantly. Confirm VAT obligations with a qualified tax adviser for your jurisdiction.

The VAT mechanics on Amazon UK:

When a VAT-registered seller lists a product at £24.99 on Amazon UK and the standard VAT rate is 20%:

• The buyer pays £24.99 (VAT-inclusive)

• The VAT portion: £24.99 ÷ 1.20 × 0.20 = £4.17

• The seller's ex-VAT revenue: £24.99 ÷ 1.20 = £20.83

• The seller remits £4.17 to HMRC

The floor calculation for a VAT-registered seller should produce a VAT-inclusive listing price, not an ex-VAT floor price. The steps:

Step 1: Calculate the ex-VAT floor from cost inputs (using net-of-VAT COGS for VAT-registered businesses, since input VAT is reclaimed)

Step 2: Multiply by (1 plus VAT rate) to convert to the VAT-inclusive floor: VAT-inclusive floor = ex-VAT floor × (1 + VAT rate) = ex-VAT floor × 1.20 (at 20% UK standard rate)

Set the minimum price in Repricer.com at the VAT-inclusive floor. This is the floor buyers see and the price Amazon pays to the seller (before Amazon's deductions).

Amazon's VAT Services:

Amazon offers VAT calculation and filing services for sellers in EU and UK markets. These services handle VAT compliance obligations but do not change the fundamental mechanic that the seller remits a portion of the listed price as VAT. The floor adjustment for VAT is required regardless of whether the seller uses Amazon's VAT services or manages VAT independently.

Step-by-step: recalculating your minimum prices with accurate tax figures

The recalculation process applies to sellers who have never included income tax in their floor (most sellers) and VAT-registered UK/EU sellers who have set floors on VAT-inclusive prices without accounting for the VAT element.

Confirm your applicable tax rates with a qualified professional before implementing these adjustments.

Step 1: Establish your effective income tax rate

Work with a tax professional to determine the effective combined rate (federal plus state income tax, plus self-employment tax where applicable) on net business profit at the expected income level. Do not use the marginal rate, use the effective rate on the expected net profit.

Step 2: Calculate the required pre-tax margin for each target after-tax margin

Required pre-tax margin = target after-tax margin ÷ (1 minus effective income tax rate)

Example at 25% effective tax rate:

• Target 10% after-tax margin → required pre-tax margin = 10% ÷ 0.75 = 13.3%

• Target 15% after-tax margin → required pre-tax margin = 15% ÷ 0.75 = 20.0%

Step 3: Recalculate the floor for active repricing ASINs

For each ASIN, apply the formula: Floor = (COGS + prep cost + FBA fee) ÷ (1 minus referral fee rate minus required pre-tax margin rate)

Pull FBA fees from the current fee schedule in the Amazon seller fees guide.

Step 4: For UK/EU VAT-registered sellers, convert to VAT-inclusive floor

VAT-inclusive floor = ex-VAT floor × (1 plus applicable VAT rate)

Step 5: Compare to current minimum prices in Repricer.com

In Repricer.com, check the current minimum price for each active ASIN. If the current minimum is below the tax-adjusted floor, update it. If using Net Margin Repricing, update the target margin input to the required pre-tax margin.

Step 6: Review quarterly

Tax obligations shift as business income changes (shifting the effective rate), as business structure changes, and as tax laws update. Review the floor calculation for tax inputs at least quarterly.

Key Takeaways

• US sales tax does not require a floor adjustment for most Amazon sellers. Marketplace Facilitator laws mean Amazon collects and remits sales tax in all 50 US states and Washington D.C. The seller's payout is based on the pre-tax selling price.

• Income tax on business profits does require a floor adjustment. The standard floor formula targets a gross margin. Income tax is paid on that gross margin. To protect a target after-tax return, the pre-tax target margin in the floor formula must be grossed up: required pre-tax margin = target after-tax margin ÷ (1 minus effective income tax rate).

• UK and EU VAT-registered sellers must calculate floors on ex-VAT prices and convert to VAT-inclusive minimums for the repricing tool. The VAT portion of the listing price is remitted to the tax authority and is not seller revenue.

• FBA inventory across multiple states creates physical nexus that is relevant for state income tax filing, not additional sales tax obligations (covered by Marketplace Facilitator for Amazon sales).

• Confirm all tax rates with a qualified professional before adjusting floor calculations. Effective rates vary by business structure, total income, and jurisdiction.

Action Plan

1. Identify your effective income tax rate with a tax professional. Include self-employment tax if applicable. Use the effective rate on expected net business income, not the marginal rate.

2. Calculate the required pre-tax margin for your target after-tax return: target after-tax margin ÷ (1 minus effective tax rate).

3. Recalculate the floor for your top 10 revenue ASINs using the tax-adjusted pre-tax margin in the formula: (COGS + prep + FBA fee) ÷ (1 minus referral fee rate minus required pre-tax margin rate).

4. If VAT-registered in the UK or EU, confirm that floors are set on VAT-inclusive prices. The ex-VAT floor × (1 plus VAT rate) gives the correct VAT-inclusive minimum.

5. Update minimum prices in Repricer.com for any ASIN where the tax-adjusted floor exceeds the current minimum. In Net Margin Repricing, update the target margin input to the required pre-tax margin.

6. Run the 10-point repricing configuration audit to confirm the complete floor configuration is accurate before the next peak selling period.

7. Schedule a quarterly review of the floor calculation for tax inputs, in parallel with annual tax return preparation.

Frequently Asked Questions

1. How do Amazon seller taxes affect my repricing minimum price?

US sales tax does not affect the repricing floor for most Amazon sellers because Amazon collects and remits sales tax under Marketplace Facilitator laws, it comes from buyers, not from seller margin. Income tax on business profits does affect the correct floor: the standard floor formula targets a gross margin without accounting for the income tax the seller will pay on that profit. To protect a specific after-tax return, divide the target after-tax margin by (1 minus the effective income tax rate) to get the required pre-tax margin, and use this adjusted margin in the floor formula. Consult a tax professional to confirm the applicable effective rate.

2. Does Amazon collect sales tax on my behalf?

Yes, for Amazon sales in the US. Under Marketplace Facilitator laws, Amazon calculates, collects, and remits sales tax to state tax authorities in all 50 US states and Washington D.C. The seller's payout from Amazon is calculated on the selling price before tax. Sellers do not need to collect or remit sales tax for their US Amazon sales, though they should retain Marketplace Tax Collection reports for their records. Multi-platform sellers and sellers with nexus in states where their non-Amazon sales trigger separate obligations should confirm their full tax position with a professional.

3. How do I include income tax in my repricing floor calculation?

Calculate the required pre-tax margin from your target after-tax margin: required pre-tax margin = target after-tax margin ÷ (1 minus effective income tax rate). Then use this required pre-tax margin in the floor formula: (COGS + prep cost + FBA fee) ÷ (1 minus referral fee rate minus required pre-tax margin rate). For example, to protect 10% after-tax at a 25% effective tax rate, the required pre-tax margin is 13.3%, and the floor formula uses 13.3% as the target margin rather than 10%. Verify the effective income tax rate for your business structure and income level with a tax professional before applying this adjustment.

4. What is the correct formula for a repricing minimum price that accounts for taxes?

For US sellers: use a two-step approach. Step 1, calculate required pre-tax margin: (desired after-tax margin) ÷ (1 minus effective income tax rate). Step 2, apply to the standard floor formula: (COGS + prep cost + FBA fee) ÷ (1 minus referral fee rate minus required pre-tax margin rate). For UK/EU VAT-registered sellers, an additional step converts the ex-VAT floor to a VAT-inclusive minimum: ex-VAT floor × (1 plus VAT rate). In all cases, confirm the applicable rates with a qualified tax professional before implementing the adjustment.

Book a Demo, configure a tax-aware repricing floor using Net Margin Repricing in Repricer.com. See the features page for the full cost stack inputs available.

This article is for educational purposes only and does not constitute tax advice. Always consult with a qualified tax professional for guidance specific to your business structure and jurisdiction.