The VAT return is ready, but box 1a shows an amount you do not recognise at all. The invoices look fine, so where does that figure come from? The answer almost always lies in the tax grids: the link between your general ledger and the boxes on the return form. Checking them before the deadline saves you from filing supplementary returns afterwards.
What is a tax grid, exactly?
Every VAT code in Odoo refers to one or more boxes of the Dutch return: 1a for supplies at the high rate, 2a for reverse-charged VAT, 4b for acquisitions from the EU, and so on. When you post an invoice, Odoo automatically adds the amount to the right box. If that link is wrong, the invoice is correct but the return is not — and you only see that when you drill down.
How to check the boxes
- Open Accounting → Reporting → Tax Report and select the return period.
- Click a box, for example 1a. Odoo immediately shows all entries that led to that amount.
- See a strange line? Drill down to the journal item and check which tax grid was applied.
- Correct the entry or adjust the VAT code on the original invoice; the report updates immediately.
Where it usually goes wrong
- Split invoices with both high-rate VAT and reverse-charged VAT: during an import, the tax grids easily end up linked incorrectly.
- Self-created VAT codes without a box, so amounts simply do not appear anywhere on the return.
- Manual journal entries on VAT accounts that bypass the boxes.
Example: a wholesaler in Zwolle imported open invoices from the old package and suddenly saw box 2a double. Cause: the reverse-charge VAT code was on the same grid on both the debit and the credit side. One tick box, problem solved.
Finally
Practical tip: schedule the check a week before the deadline, not the evening before — that leaves time to make corrections calmly. Not sure whether your VAT codes are set up correctly? Contact DAADit Group, we are happy to go through them with you.
The VAT return is ready, but box 1a shows an amount you do not recognise. The invoices look fine, so where does that number come from? The answer is almost always in the tax grids: the link between your general ledger and the boxes on the return form. Check them before the deadline and you avoid corrections afterwards.
What is a tax grid, exactly?
Every VAT code in Odoo points to one or more boxes of the Dutch return: 1a for standard-rate supplies, 2a for reverse-charged VAT, 4b for EU acquisitions, and so on. When you post an invoice, Odoo automatically adds the amount to the right box. If that link is wrong, the invoice is correct but the return is not — and you only see it when you drill down.
How to check the boxes
- Open Accounting → Reporting → Tax Report and select the filing period.
- Click on a box, for example 1a. Odoo immediately lists every entry behind that amount.
- Spot an odd line? Drill down to the journal item and check which tax grid was applied.
- Correct the entry or change the VAT code on the original invoice; the report updates instantly.
Where it usually goes wrong
- Split invoices with both standard-rate and reverse-charged VAT: during an import, the tax grids are easily linked to the wrong side.
- Custom VAT codes created without a grid, so amounts simply never appear on the return.
- Manual journal entries posted straight to VAT accounts, bypassing the grids altogether.
Example: a wholesaler in Zwolle imported open invoices from their old system and suddenly saw box 2a double. Cause: the reverse-charge VAT code pointed to the same grid on both the debit and the credit side. One checkbox, problem solved.
One last thing
Practical tip: schedule this check a week before the deadline, not the evening before — that leaves time to correct things calmly. Not sure your VAT codes are set up correctly? Get in touch with DAADit Group and we will gladly walk through them with you.