DIČ (daňové identifikační číslo) — this is a tax identification number given by the finanční úřad (tax office).
DIČ ≠ IČO
- IČO — your number as a business owner, from the trade register.
- DIČ — your number with the tax office.
These are different numbers from different registers, and you should not mix them up on documents.
Where DIČ is required
On a daňový doklad (tax document) from a plátce DPH (VAT payer) (§ 29 of the VAT Act), the DIČ is shown for both the supplier and the buyer, if the buyer is also a VAT payer.
What to use instead for a non-payer
A non-payer issues an účetní doklad (accounting document) (§ 435 of the Civil Code) with the IČO, company name, address, and registration details — no VAT details. The recommended note is: «Nejsem plátce DPH» (I am not a VAT payer).