It’s free to SORN a car. You can do it online at the government’s website, by phone or by post. To declare a SORN online, you need either: The 16-digit reference number on your tax renewal letter (this is the V11). If you don’t have this, you can find it by logging into your personal account on the DVLA website. Once you’ve declared a SORN, it lasts for 12 months and starts from the date you make the declaration. You can renew it after 12 months, as long as your car is still off the road. If you want to put your car back on the road during that time, you’ll need to pay for vehicle tax and insurance first. If you have any questions about SORN or how to declare it, you can contact the DVLA for more information.