The urencriterium (hours criterion) of 1,225 hours a year
The urencriterium (hours criterion) decides whether you get the zelfstandigenaftrek (self-employed deduction) and the startersaftrek (starter's deduction). You spend at least 1,225 hours on your business in the calendar year. (Belastingdienst: conditions of the hours criterion)
Also if you start halfway
Do you start or stop during the year? You still have to reach the full 1,225 hours. The number is not reduced pro rata.
Which hours count?
Not only the hours that you invoice to clients count. Hours for your business itself also count, such as:
- your records and your VAT return;
- finding clients, quotes and networking;
- your website and marketing;
- travel time for your work.
Proof
The Belastingdienst can ask you to show that you worked the hours. So keep a record of what you did, per day or per week. A diary or hours overview is good proof.
What if you do not reach it?
If you do not reach the 1,225 hours, you get no zelfstandigenaftrek and no startersaftrek. You do still get the MKB-winstvrijstelling (SME profit exemption).
In ZZPboek
In Hours and kilometres, you record your hours, including non-billable hours. The app adds them up per year and shows how many hours you still need to reach 1,225.

Sources
This article is general information, not tax advice. If you are unsure about your situation, ask the Belastingdienst or an adviser.