What does my new company actually have to file?
The same two yearly jobs every limited company has, sent to two different places:
- Accounts to Companies House (the public record of your company's figures).
- A Company Tax Return to HMRC, once HMRC sends you a letter asking for one. This usually arrives soon after your company starts trading.
So far, so normal. The thing that makes the first year different is the dates, and the fact that your first stretch of time is usually longer than a normal year.
Why is the first year longer than 12 months?
When you set your company up, Companies House gives it a yearly date to count from, called your accounting reference date. It's the last day of the month you set the company up in, one year on. Set your company up on 14 June 2025, and your date is 30 June 2026.
Your first accounts run from the day you set the company up to that date. From 14 June 2025 to 30 June 2026 is more than 12 months. That's normal for a first year, and it's where the confusion starts.
So why might I file two tax returns?
A tax return can only ever cover up to 12 months. Your first accounts cover more than that. So HMRC splits your first stretch into two periods, and you file one tax return for each:
- One return for the first 12 months.
- A second return for the leftover days at the end.
Companies House is different. It still gets one set of accounts covering the whole first stretch. So you end up with one lot of accounts but two tax returns. That mismatch is the single thing first-timers find most confusing, and it's the bit we handle for you.
This only happens because the first period is long. From your second year on, your year is a normal 12 months, and you're back to one set of accounts and one tax return.
A real example, with real dates
Say you set your company up on 14 June 2025. Companies House sets your yearly date as 30 June 2026, so your first accounts cover 14 June 2025 to 30 June 2026, a bit over 12 months.
That one set of accounts splits into two tax periods for Corporation Tax. Both tax returns share the same send-by date, 12 months after the end of your whole first stretch. The dates to pay the tax come earlier, and they are different for each period:
| Period it covers | Pay the tax by | Send the tax return by | |
|---|---|---|---|
| First tax return | 14 Jun 2025 to 13 Jun 2026 | 14 March 2027 | 30 June 2027 |
| Second tax return | 14 Jun 2026 to 30 Jun 2026 | 1 April 2027 | 30 June 2027 |
And the accounts themselves go to Companies House on their own clock:
| What it covers | Send it by | |
|---|---|---|
| First accounts (Companies House) | 14 Jun 2025 to 30 Jun 2026 | 14 March 2027 |
Your first accounts get a long runway: they're due 21 months after the day you set the company up, not the usual 9 months. After this first year, that drops back to the normal 9 months after your year ends.
Does the longer first year change the tax I pay?
It can, in a way that catches people out. The £50,000 and £250,000 profit figures that decide your tax rate are scaled down for any period shorter than a full 12 months. Your second tax period (the leftover days) is very short, so its figures shrink a lot. A small profit in that short stretch can land you in a higher rate than you'd expect.
You don't work any of this out. We read your period's start and end dates and scale the figures for you, then apply the right rate.
What if my company barely traded, or made a loss, in its first year?
You still file. Once HMRC has sent you that letter asking for a return, you send one even if your company made a loss or earned nothing in its first year. A company that did nothing at all files a lighter "dormant" version instead, and we help you work out which one you are.
How SimpleReturns handles your first year
Tell us the day you set your company up, and we work out your accounting reference date, whether your first accounts run past 12 months, and every deadline that follows. If your first period needs two tax returns, we build both and split the figures across them correctly, then send one set of accounts to Companies House and your return (or returns) to HMRC. You never have to work out which period is which, or which date is which.