# HMRC SA103 Accounting Date: 'Date Your Books or Accounts Are Made Up To' & Basis Period Reform Guide (2026/27)

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- **Jurisdiction / Region:** UK
- **Last Verified:** Mon Nov 02
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- **Summary:** What to enter for 'date your books or accounts are made up to' on HMRC SA103 (2025/26 & 2026/27): 5 April vs 31 March rule, basis period reform & Box 68–73.

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# HMRC SA103 Accounting Date: 'Date Your Books or Accounts Are Made Up To' & Basis Period Reform Guide (2026/27)

**Short answer: When HMRC Self Assessment asks for the date your books or accounts are made up to (Box 8 on SA103S or Box 9 on SA103F), enter 05/04/2026 (or 31/03/2026 if you close your books at the end of March) for the 2025/26 tax return, or 05/04/2027 (31/03/2027) for 2026/27. Under HMRC Basis Period Reform (ITTOIA 2005 section 7A), all UK sole traders are taxed on the tax year basis (6 April to 5 April), and HMRC treats any accounting date from 31 March to 4 April as equivalent to 5 April.**

> **⚡ Instant UK HMRC `SA103S / SA103F`, `45p/25p` Mileage & Sole Trader Invoice Toolkit (`£GBP`):** Estimate your 2026/27 Income Tax, Class 4 National Insurance, and Payments on Account in our **[Free UK Self-Employed Tax Calculator](/keel/self-employment-tax-calculator/)** below (or click **🔗 Embed / CSV Template**), save up to **5 Free Saves in your [iCloud Web Workspace](/keel/workspace/)**, read our **[HMRC Form SA103S & SA103F Box-by-Box Guide](/keel/uk-sa103s-and-sa103f-self-employed-form-guide/)**, compare the **[UK Self Assessment SA103 App Store Edition](/keel/cpp/uk-self-assessment-sa103/)**, or **[Download Keel Free on the App Store (`£0/mo` UK Sole Trader Edition)](https://apps.apple.com/gb/app/keel-invoice-maker-receipts/id6786659713?ppid=72e63a40-1434-4f95-a3dc-62eceeb19abd)** (`uk-self-assessment`).

One of the most searched questions every January as sole traders fill out their online **HMRC Self Assessment** return is: *what do I put for the "date your books or accounts are made up to" on the Self-Employment pages (`SA103S` / `SA103F`)?*

Before April 2024, a sole trader could pick any year-end date (such as `30 April` or `31 December`) and be taxed on that accounting year (`the current year basis`). Following HMRC's **[Basis Period Reform](https://www.gov.uk/guidance/basis-period-reform)** (`Finance Act 2022` Schedule 1), every unincorporated sole trader and partnership in the UK is now taxed strictly on the **Tax Year Basis (`6 April to 5 April`)**—which also aligns directly with **[Making Tax Digital for Income Tax (`MTD for IT`)](/keel/uk-making-tax-digital-sole-traders/)** starting **6 April 2026**.

Below is the exact box-by-box guide for entering your accounting date on **`SA103S` (`Box 8`)** and **`SA103F` (`Boxes 8–9` & `Boxes 73.1–73.4`)**, how the **31 March to 5 April equivalence rule** works, and how to report **5-year spread transitional profits (`2023/24` to `2027/28`)**. For companion UK guides, see [Self Assessment for the self-employed](/keel/uk-self-assessment-self-employed/) and [cash basis vs accrual accounting on SA103](/keel/uk-cash-basis-vs-accrual-accounting-sole-trader-sa103-guide/).

## What should you enter for `date your books or accounts are made up to` on `SA103S` / `SA103F`?

Use the table below to enter the exact date in **`Box 8` of Form `SA103S` (Short)** or **`Box 9` of Form `SA103F` (Full)**:

| Your Sole Trader Situation | **2025/26 Tax Return** *(Online deadline: 31 Jan 2027)* | **2026/27 Tax Return** *(Online deadline: 31 Jan 2028)* | Why HMRC Accepts This Date |
|---|---|---|---|
| **Standard Tax Year Bookkeeping *(Most UK sole traders & CIS subcontractors)*** | **`05/04/2026`** *(Accounting period: `06/04/2025` to `05/04/2026`)* | **`05/04/2027`** *(Accounting period: `06/04/2026` to `05/04/2027`)* | Matches the official UK tax year end (`5 April`) to the day |
| **Calendar-Month Bookkeeping *(Closing books at the end of March)*** | **`31/03/2026`** *(Accounting period: `01/04/2025` to `31/03/2026`)* | **`31/03/2027`** *(Accounting period: `01/04/2026` to `31/03/2027`)* | Under **`ITTOIA 2005 s 7A`**, HMRC treats any accounting date from **31 March to 4 April** as ending on **5 April** (no time-apportionment required) |
| **Started Self-Employment Mid-Year** *(e.g. started trading on `12 September 2025`)* | **Start date (`Box 6`):** `12/09/2025` · **Books made up to (`Box 8`):** **`05/04/2026`** (or `31/03/2026`) | **Books made up to (`Box 8`):** **`05/04/2027`** (or `31/03/2027`) | In your first tax year, you report from your actual start date up to `5 April` (or `31 March`) |
| **Stopped Trading / Closed Sole Trader Business Mid-Year** *(e.g. ceased on `30 November 2025`)* | **Cessation date (`Box 7`):** `30/11/2025` · **Books made up to (`Box 8`):** **`30/11/2025`** | No `SA103` required if you did not trade in `2026/27` | When you permanently cease trading, your final accounts are made up to your cessation date |

## Why does HMRC treat `31 March` and `5 April` as the same date (`ITTOIA 2005 s 7A`)?

Many sole traders and accountants prefer to run monthly bookkeeping from **`1 April` to `31 March`** rather than cutting a month in half on **`5 April`**. Under **Section 7A of the Income Tax (Trading and Other Income) Act 2005 (`ITTOIA 2005`)**:

- If your accounts are drawn up to **`31 March`**, **`1 April`**, **`2 April`**, **`3 April`**, or **`4 April`**, the profits or losses of those 5 days (`1 April – 5 April`) are automatically treated as falling into the **following** tax year's accounts.
- You do **not** have to manually split out invoices or expenses dated `1 April – 5 April` if your chosen accounting date is `31 March`—provided you stay consistent from year to year (`1 April 2025 – 31 March 2026`, then `1 April 2026 – 31 March 2027`).
- Under **[Making Tax Digital for Income Tax (`MTD for IT`)](/keel/uk-making-tax-digital-sole-traders/)** (mandatory from **6 April 2026** if your qualifying turnover exceeds **£50,000**), HMRC explicitly allows you to elect **calendar quarters (`1 April – 30 June`, `1 July – 30 September`, `1 October – 31 December`, `1 January – 31 March`)** so your MTD quarterly updates match a `31 March` accounting date without changing a single filing deadline (`7 August`, `7 November`, `7 February`, `7 May`).

## What if you keep a non-tax-year accounting date (e.g. `31 December`) or have Transitional Profits (`Boxes 73.1–73.4`)?

While 95%+ of UK sole traders use `5 April` or `31 March`, two special rules apply on **`SA103F` (Full Self-Employment pages)** if you had a different accounting year-end before 2023/24:

1. **Continuing with a non-tax-year date (e.g., `31 December`):**
   - Under the Tax Year Basis, you must use **Form `SA103F` (Full)** (you cannot use `SA103S` Short) and **time-apportion** two sets of accounts by days (`9 months / 275 days` of the first set + `3 months / 90 days` of the second set) to arrive at your `6 April – 5 April` taxable profit. Because the second set of accounts may not be finalised by 31 January, you may have to submit provisional figures and amend your return later—which is why HMRC strongly recommends changing your accounting date to **`31 March` or `5 April`**.
2. **Spreading Transitional Profits from `2023/24` (`SA103F Boxes 73.1 to 73.4`):**
   - If you had a non-March/April year-end in `2023/24` and deducted your accumulated **Overlap Relief** during the transition year, any remaining **transition profit** is automatically spread in equal **20% (`1/5th`) instalments across 5 tax years (`2023/24`, `2024/25`, `2025/26`, `2026/27`, and `2027/28`)**.
   - On your **2025/26** and **2026/27** `SA103F` returns, enter the 20% annual instalment brought forward (or elect to accelerate more of it) in **Boxes `73.1` to `73.4`**. If you cease trading before `2027/28`, any remaining unspread transition profit becomes taxable in your final year of trading.

## How to keep your `6 April – 5 April` SA103 ledger clean all year

With **[Keel (`£0/mo` Core on iPhone & iCloud Web Workspace)](/keel/cpp/uk-self-assessment-sa103/)**, your UK tax year is pre-configured to **`6 April – 5 April`** out of the box—automatically grouping your sole trader invoices, `SA103S` Box 11–19 allowable expense receipts, `45p/25p` mileage logs, and `20% CIS` subcontractor statements into a 5-year HMRC audit pack with **no Open Banking connection required**.

## Step-by-step checklist before submitting Box 8 (`SA103S`) or Box 9 (`SA103F`)

1. Confirm whether your bookkeeping runs to **`05/04/2026`** (exact tax year) or **`31/03/2026`** (calendar-month end under `ITTOIA 2005 s 7A`).
2. Check **`Box 10` (`SA103S`)** if you use the default **Cash Basis** (leave it unticked; only tick `Box 10` if you elected traditional accrual accounting).
3. Verify that all invoices and expenses fall within your 12-month period and save your 5-year record pack.

## Frequently asked questions

**What do I put for "date your books or accounts are made up to" on my HMRC Self Assessment return?**

For the **2025/26 UK tax year** (`6 April 2025 to 5 April 2026`), enter **`05/04/2026`** in `Box 8` of `SA103S` (or `Box 9` of `SA103F`) if you run your books on the standard tax year, or **`31/03/2026`** if you close your books at the end of March. For the **2026/27 tax year**, enter **`05/04/2027`** (or **`31/03/2027`**).

**What if I started being self-employed halfway through the tax year?**

Enter the exact date you started trading in **`Box 6` (`If your business started after 5 April...`)**, and still enter **`05/04/2026`** (or **`31/03/2026`**) as the **date your books or accounts are made up to** in `Box 8`. Your turnover and expenses on that first return cover the period from your start date to `5 April` (or `31 March`).

**Does it matter whether I choose `31 March` or `5 April` as my accounting date?**

For HMRC tax purposes, both dates are treated identically. Under *section 7A of ITTOIA 2005*, HMRC treats any accounting date between **31 March and 4 April** as ending on **5 April**, so you never have to apportion the 5 days between `1 April` and `5 April` so long as you use the same date consistently each year.

**Can I still have a `30 April` or `31 December` year-end as a UK sole trader?**

Technically you can still draw up internal accounts to another date, but under HMRC's **Basis Period Reform**, you are taxed strictly on the profits arising in the **tax year (`6 April to 5 April`)**. Using any date outside `31 March – 5 April` forces you to file the full `SA103F` pages and time-apportion two accounting periods every single year.

**What happened to Overlap Relief on Form SA103?**

Under Basis Period Reform, all existing **Overlap Relief** had to be claimed in the `2023/24` transitional tax year (or via an amendment to the `2023/24` return). From `2024/25` through `2027/28`, sole traders who generated net transitional profits in `2023/24` simply report their annual **20% (`1/5th`) spread transition profit** in **Boxes `73.1–73.4` of `SA103F`**.

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*This guide is general information based on HMRC Self Assessment (`SA103S Notes` / `SA103F Notes`) and the Income Tax (Trading and Other Income) Act 2005 (`s 7A`) for the 2025/26 and 2026/27 tax years, and is not personal tax advice. Check gov.uk or speak to a qualified UK accountant.*