Fee data / controlled inputs
Platform rates need an audit trail.
MarginTally versions every built-in platform rate by market and verification date. A production release stops if the official source cannot be reopened or has changed.
Current fee registry
Etsy US fee version: 2026-09-01-v1. It includes a $0.20 listing fee, 6.5% transaction fee, US Etsy Payments rate of 3% + $0.25, and selectable 12% or 15% Offsite Ads with a $100 order cap.
The Amazon Ads calculator uses official definitions for ACoS and ROAS. It does not contain built-in Amazon referral or FBA fee tables.
Official sources
- Amazon Ads: ACoS guide — verified September 1, 2026.
- Etsy: fees and taxes for selling — verified September 1, 2026.
- Etsy: payment processing fees — verified September 1, 2026.
Maintenance rule
- Open each official source before a production release.
- Compare every modeled rate, base, cap, market, and rounding rule.
- Record a new version when any value changes.
- Mark the calculator review-required and stop release if verification is incomplete.
This is a production-candidate snapshot, not evidence that rates remain current after the displayed verification date.