[PSA / Math] Q4 Holiday Peak fees start Oct 15: How much phantom profit is your sourcing sheet calculating right now?

Posted by u/ratecard_w

Hey everyone,

With Q4 sourcing in full swing, I was doing a reconciliation on my projected margins versus actual FBA settlement reports and noticed a recurring gap in profit projections across free calculators and older spreadsheets.

If you're sourcing inventory right now that will sell between Oct 15 and Jan 14, Amazon adds the Holiday Peak fulfillment fee (typically +$0.32 to +$0.40+ on standard sizes), on top of the 3.5% fuel/inflation surcharge and inbound placement fees.

Here is a real breakdown on a standard 1.2 lb item selling at $26.99 (Buy Cost: $11.50):

- Baseline Free Extension Estimate (Older rate card):

FBA Fulfillment: $4.15

Referral Fee: $4.05

Net Profit: $7.29 | ROI: 63.4%

- Actual 2026 Q4 Rates (Effective Oct 15):

FBA Base: $4.15

+ Peak Surcharge: +$0.38

+ 3.5% Fuel Surcharge: +$0.16

+ Inbound Placement (Minimal Split avg): +$0.27

Referral Fee: $4.05

True Net Profit: $6.48 | ROI: 56.3%

That's an $0.81 profit variance per single unit. On a 40-unit test buy, that’s $32.40 of "phantom profit" that never actually hits your bank account.

I got tired of crunching these adjustments manually, so I built a lightweight Chrome tool for myself (SheetSniper) that live-calculates with the official 2026 fee formulas right on the Amazon product page and pushes the whole row (ASIN,dims, weight, fees, net ROI) directly to Google Sheets in 1 click so I don't have to copy-paste.

The calculator itself is 100% free with no account or email needed. If anyone wants to test the math on their own ASINs or wants the Chrome Web Store link, let me know in the comments and I'm　happy to share!

What sellers replied

u/ratecard_w

Quick follow-up for anyone checking their sourcing numbers this weekend: If you're sourcing Small Standard items under 1 lb, the peak fee bump is slightly lower (~$0.25-$0.30), but the 3.5% fuel still applies across the board. Curious what categories everyone is seeing the biggest fee creep in right now?