Turns out the calculation is correct, I just was unclear on how it works. It’s explained pretty well here:
https://help.shopify.com/en/manual/taxes/location#include-taxes-in-product-prices
Tax = (Tax Rate X Price) / (1 + Tax Rate)
Topic summary
Issue: Checkout tax amounts in a Finland-registered store appeared too low versus set rates (e.g., from 50€ total, tax shown was 6.14€ at 14% and 9.68€ at 24%).
Key context: EU settings with a 14% product tax override; default rate 24%. Concern that percentages didn’t match 14%/24% of the total.
Suggestion offered: Review Shopify tax rounding settings (Settings → Taxes → Tax rounding) and try “Nearest.”
Resolution: Calculations are correct because prices are tax-inclusive. Shopify extracts the tax portion from the displayed price using the formula: Tax = (Tax rate × Price) / (1 + Tax rate). Example: 50 × 0.14 / 1.14 = 6.14; 50 × 0.24 / 1.24 ≈ 9.68.
Outcome: Misunderstanding clarified; no platform bug. Rounding settings may affect cent-level rounding but weren’t the root cause.
Notes: Understanding the difference between tax-inclusive pricing (common in EU) and tax-exclusive pricing is essential. A linked Shopify help article (Include taxes in product prices) is central to the explanation.