tl;dr
Amazon sometimes applies the wrong VAT rate to products — for example the wrong rate for a specific country or product category
If left uncorrected, this causes Klar to calculate net revenue and contribution margins incorrectly
The Amazon Tax Correction Sheet lets you define the correct tax rate per ASIN, per country, and per date range — Klar then uses these values instead of Amazon's
You can apply a correction to a single product or to all products at once using
ALLin the ASIN field
Why this is needed
Amazon reports revenue and tax data per order, but it sometimes applies the wrong VAT rate — for example because of a product category mismatch, a VAT rate change that wasn't applied retroactively, or a country-specific exception. Since Klar uses Amazon's reported data to calculate net revenue and margins, an incorrect tax rate flows through into all your downstream metrics: CM1, CM2, ROAS, and CAC.
The Amazon Tax Correction Sheet lets you tell Klar the correct tax rate for a specific product in a specific country over a specific period. Klar then applies your override when processing the data.
Getting the template
In Klar, go to Store Configurator → Data Sources → Add Data Source
Select Amazon Tax Sheet
Just name it Amazon Tax and Klar will generate a new Google Sheet for you — open it from the datasource settings
The sheet has one tab: CustomCostsSheet. Your data starts at Row 4 (Row 2 contains field descriptions, Row 3 contains column headers).
Field reference
All five fields are required.
Date Start (col A — format: dd/mm/yyyy) The first date the tax rate correction applies. For a correction that applies to a single day, enter the same date in both Date Start and Date End.
Date End (col B — format: dd/mm/yyyy) The last date the tax rate correction applies. For ongoing corrections with no fixed end, use a date far in the future (e.g. 31/12/2099).
ASIN (col C) The Amazon product identifier the correction applies to. To apply the correction to all products, enter ALL.
Two Letter Country Code (col D) The country the tax rate applies to, using the ISO two-letter code. Examples: DE for Germany, FR for France, GB for the United Kingdom, IT for Italy.
Tax Rate (col E) The correct VAT rate. You can enter it either as a percentage (19%) or as a decimal (0.19) — both formats are accepted.
Examples
Date Start | Date End | ASIN | Country | Tax Rate | What it does |
01/01/2023 | 31/12/2099 | A81781ACD2 | DE | 19% | Applies 19% VAT to a specific product in Germany from Jan 2023 onwards |
01/07/2021 | 30/06/2022 | ALL | FR | 5.5% | Applies a reduced rate to all products in France for a specific period |
15/03/2024 | 15/03/2024 | B00XYZ123 | AT | 10% | Corrects a single day for one product in Austria |
How to apply multiple corrections
Each row is a separate rule. You can add as many rows as needed — for example:
One correction per country if the same product has different VAT issues across markets
A historical correction (with a past end date) plus an ongoing correction (with a future end date) for the same product
A catch-all
ALLcorrection for a country-wide VAT change, plus a product-specific override for an exception
Rules are matched by ASIN + country + date, so a more specific ASIN rule takes precedence over an ALL rule if both apply.
Syncing your data
Once filled in, sync the datasource so Klar picks up your corrections:
Go to Store Configurator → Data Sources and open the Amazon Tax Correction datasource
Click Sync Data
Check the Status column (col F) in the sheet — Klar writes the import result here for every row after each sync:
✅
Success @ [timestamp]— the row was imported successfully❌
[error description]— the row was rejected. Fix the issue and sync again.
Go to Store Settings → Update Store Data to rebuild your reports with the corrected tax rates