Making Tax Digital (MTD) for Income Tax requires a quarterly update to HMRC for each income source — four times a year. This article covers how to prepare and submit those updates in Dext Solo, whether you're an accountant or bookkeeper managing a client's account, or a Solo client submitting your own updates.
Before you start
Before submitting, a few things need to be in place.
If you're an accountant or bookkeeper, your practice must be connected to HMRC, and the client's income sources must be linked to their HMRC records. For instructions, go to How to connect Dext to HMRC for MTD for Income Tax.
If you're a Solo client submitting your own updates, your accountant or bookkeeper must enable this from your account settings first. Go to How to enable client submissions in Dext Solo for instructions. Once enabled, you'll need to complete your own HMRC connection — your accountant or bookkeeper can guide you through this, or go to the article above for the steps.
You should also have worked through the quarter's records before submitting. This means you've either:
Added and coded documents in the Costs or Sales workspace, and/or
Matched or cash-coded transactions in the Bank workspace
The goal is a set of digital records that accurately reflects the income and expenses for that quarter. You should also have reviewed the Items to review report to confirm everything that needs categorising has been actioned — uncategorised items can affect the accuracy of the figures you submit.
Who can access the HMRC submissions page
Access to the HMRC submissions page depends on your user role.
If you're part of a practice, the page is available to Practice Admins and Client Admins. Standard users don't currently have access to this page, though this may change in a future update.
If you're a Solo client, you need to be a Business Admin or User Admin on the account. Your accountant or bookkeeper must also have enabled HMRC submissions access for you — go to How to enable client submissions in Dext Solo for instructions on that.
Understanding the HMRC submissions page
The HMRC submissions page gives you a view of all quarterly update obligations for the selected tax year.
Go to HMRC submissions in the left navigation of a Dext Solo account to open it.
Each block on the page represents one quarter. Within each block, there's a row for each income source — for example, a self-employed business and a UK property income source. Each income source requires a separate submission.
Each row shows the income source name and its current status: Due, Submitted, or Overdue.
Use the tax year drop-down in the top right to switch between tax years. Select Refresh obligations to pull the latest obligations from HMRC if the page doesn't reflect what you expect.
Submission windows
Submissions can only be made during the submission window for each quarter. The window opens 10 days before the period end date and closes on the deadline. Outside this window, the obligation is listed, but the Submit option isn't available.
Most accounts use standard quarters. Some may have opted into calendar quarters, which use calendar month-end dates instead.
Standard quarters
Quarter | Period | Window opens | Deadline |
Q1 | 6 Apr – 5 Jul | 25 Jun | 7 Aug |
Q2 | 6 Jul – 5 Oct | 25 Sep | 7 Nov |
Q3 | 6 Oct – 5 Jan | 26 Dec | 7 Feb |
Q4 | 6 Jan – 5 Apr | 26 Mar | 7 May |
Calendar quarters
Quarter | Period | Window opens | Deadline |
Q1 (year 1 only) | 6 Apr – 30 Jun | 20 Jun | 7 Aug |
Q1 (subsequent years) | 1 Apr – 30 Jun | 20 Jun | 7 Aug |
Q2 | 1 Jul – 30 Sep | 20 Sep | 7 Nov |
Q3 | 1 Oct – 31 Dec | 21 Dec | 7 Feb |
Q4 | 1 Jan – 31 Mar | 21 Mar | 7 May |
Note: Calendar quarters must be set up before the first quarterly submission of the tax year and can't be changed mid-year. Go to How to change the quarterly period type for a Solo client for instructions.
Tax estimate so far
The right-hand panel shows a running tax estimate based on what's been submitted to HMRC. It shows estimated tax due and estimated NIC due, along with any NIC notices that apply to the account (for example, Class 2 or Class 4 exemptions).
If the final year declaration hasn't been submitted yet, a warning will appear in the panel. You can submit the final year declaration directly from the panel using the Submit final year declaration in HMRC link.
Select Refresh to pull the latest calculation from HMRC. The estimate is for guidance only and may not reflect the final tax owed.
Preparing a quarterly update
To prepare a quarterly update, open the HMRC submissions page and select Prepare on the income source row you want to submit. The Prepare button is only available when the submission window is open, and the income source shows a Due status.
The preparation screen shows:
The income source name and the period being reported
A profit/loss figure and an income/expenses bar for the period
A breakdown of business income and business expenses by tax box number
These figures are drawn directly from the transactions coded in Dext for that income source and period.
Checking the figures
To check what sits behind any of the totals, select the View SA103E report link on the left for self-employed income sources, or the View SA105 report link for rental property income sources. This opens the tax report filtered to the relevant income source and period, allowing you to drill down to subcategories and individual items.
Warnings to look out for
2 types of warning may appear on the preparation screen:
A yellow banner at the top means some entries for the period aren't correctly categorised. Select the Items to review link in the banner to review them before submitting.
A yellow panel on the left means differences have been detected between this submission and the current report — for example, if transactions have been added or changed since you last submitted. Affected tax box figures show the previous and current amounts side by side. Review the figures and submit an amendment if needed.
Jointly let properties
If the income source is a jointly let rental property, 2 widgets appear at the bottom of the preparation screen:
Beneficial interest export — if you're the primary owner, use this to preview or export each co-owner's share of income and expenses as a CSV for their own HMRC reporting.
Beneficial interest import — if you're a co-owner, use this to import a beneficial interest statement exported from the primary owner's account, so your share of the jointly let property income and expenses is included in your submission.
For full details on how jointly let properties work, go to How jointly let properties work in Dext Solo.
Submitting the update
To submit the quarterly update to HMRC once you're satisfied the figures are accurate:
Tick the confirmation checkbox at the top of the screen: "I confirm that, to the best of my knowledge, these numbers are correct."
Select Submit.
If this is your first submission for the tax year, a Confirm quarterly period type panel appears. It confirms which quarterly period type — standard (fiscal) or calendar — will apply for the rest of the year. Once you submit, the period type can't be changed until the next financial year. If you need to change it first, select Income Sources in the panel, update the period type, then return to submit. Otherwise, select Confirm to proceed.
The update is sent to HMRC directly. The income source row on the submissions page will show a Submitted status and the date it was filed.
Note: If you're outside the submission window, the Submit button won't be available. Go to the submission windows tables above for exact dates.
Viewing submission history
To review past submission activity, go to the bottom of the HMRC submissions page.
The history log shows recent submissions, including who filed each update and whether it was submitted by the practice or the Solo client.
For a full record of past submissions, select Submission history in the left navigation.