How to register for Corporation Tax

Incorporation and tax registration are separate steps. Companies House creates the company; HMRC needs to know when it actually starts doing business, because that starts your first accounting period for Corporation Tax. You have 3 months from the date business activity begins to register. Many companies formed through Companies House’ online service are enrolled for Corporation Tax at the same time — check your paperwork before assuming either way.

1. Wait for the UTR letter — HMRC posts the company’s 10-digit Unique Taxpayer Reference to the registered office within about 14 days of incorporation
2. Create or sign in to the company’s Government Gateway account (the company’s, not your personal one)
3. Register for Corporation Tax online — you’ll give the date business started, your accounting reference date and what the company does
4. Note the dates HMRC confirms — your first accounting period and when your first payment and return will be due

An accountant can handle registration as your agent — we do it as standard within company formation support and for companies coming out of dormancy.

Formation and registrations, done for you →

Once registered, the clock runs on your first accounting period: Corporation Tax payment 9 months and 1 day after the period ends, and the CT600 return 12 months after. Because a first period usually runs slightly over 12 months, expect two returns for year one. None of this generates bills through the post at the right moment — the dates are yours to know.

The first-year timeline in full →

Send us your incorporation certificate and UTR letter and we’ll register the company, confirm every date, and set up the bookkeeping that makes the first return painless. Call 0114 327 1480.

Our Corporation Tax service →