Final-Week Q1 Reconciliation: Mixed Income Check Before August

Six Weeks Out: Why This Moment Matters

The 7 August deadline for your first MTD quarterly update is six weeks away. If you have both self-employment income and rental income, this is the week to stop adding records and start checking them. Not filing is not an option - late updates carry penalties. But filing inaccurate figures is nearly as bad. This post is a practical reconciliation checklist for the final stretch, covering how to cross-check your profit and loss, sort any uncategorised expenses, confirm which allowances apply to which income stream, and do the spot-checks that catch errors before they become problems.

Step 1: Pull Together Your Q1 Figures in One Place

Before you can reconcile anything, you need to see all your Q1 figures side by side. That means your self-employment income and expenses in one column, and your rental income and expenses in another. These are separate income streams for MTD purposes, and HMRC expects them reported separately.

If you have been using spreadsheets, open them now and check you have not accidentally mixed expenses across the two streams. It is a common mistake - a broadband bill claimed under rental expenses when it was actually a business cost, or a landlord insurance premium sitting in the wrong category.

If you are using bridging software like AffordableMTD, check that your imported data has landed in the correct income type. You should be able to see your self-employment figures and property income figures as two distinct sets before you submit anything.

Not sure your setup is correct? The post on mixed income and MTD for landlords with self-employment covers how the two income streams should be structured in your software from the start.

Step 2: Reconcile Your Self-Employment Profit and Loss

Income side

Go through every payment you received between 6 April and 5 July 2026 from your business or freelance work. Check your bank statements line by line against your recorded income. Ask yourself:

• Is every invoice payment in your records?
• Are there any payments you received but have not logged?
• Have you included any rental receipts in your business income by mistake?
• Are there any refunds or credit notes that need to reduce your gross income figure?

For common mistakes on the income side, the post on sole trader Q1 MTD income mistakes is worth a quick read before you finalise anything.

Expenses side

Check each expense you have recorded for your self-employment. Every item should have a category. If you still have uncategorised transactions sitting in your records, now is the time to deal with them - not after you have filed.

Allowable expenses for sole traders typically include:

• Office supplies and stationery
• Business phone and broadband (the business-use proportion)
• Software subscriptions used for work
• Professional fees
• Marketing costs
• Vehicle costs - either actual costs or mileage using simplified rates
• Training directly related to your trade

If you are using mileage rates rather than actual vehicle costs, check your mileage log covers the whole quarter. The first 10,000 miles in a tax year can be claimed at 45p per mile for cars. More detail is in the post on mileage allowances and simplified rates for Q1.

For a broader guide on what counts as allowable, see allowable expenses for MTD sole traders and landlords.

Step 3: Reconcile Your Rental Income and Expenses

Income side

List every rental payment received between 6 April and 5 July. Cross-reference against your bank statements. Things to watch out for:

• Rent paid late from March - does it belong in Q1 or Q4 of the previous period?
• Deposits held in trust - these are not income
• Any service charges or utility recharges passed through to tenants
• Payments from multiple properties - each one should be in your records

If you have not filed an MTD quarterly update for rental income before, the post on first MTD Q1 filing for landlords explains what property income must include.

Expenses side

Rental expenses are different from business expenses. The allowable costs for a landlord include:

• Letting agent fees
• Landlord insurance
• Repairs and maintenance (not improvements)
• Ground rent and service charges
• Utility bills you pay as landlord
• Accountancy fees for the rental business
• Mortgage interest - subject to the rules on finance cost restriction

Note that you cannot claim capital improvements as an expense. Replacing a broken boiler is a repair. Adding a boiler where there was not one before is an improvement. The distinction matters.

Step 4: Keep the Two Income Streams Separate

This is worth its own section because mixed-income filers get this wrong more often than any other group. Your self-employment and your rental income are two separate businesses in HMRC's eyes. They are reported in separate sections of your quarterly update. Expenses from one cannot be claimed against the other.

Common cross-contamination errors to check for:

• Home office costs split proportionally but allocated entirely to one income type
• Accountancy fees charged once but covering both streams - split them
• A single phone bill used partly for the rental business and partly for self-employment - the split should reflect actual use
• Vehicle costs for visiting both tenants and clients - you need separate mileage logs for each

There is more detail on how to handle multiple income sources correctly in the post on multiple income sources and MTD for the self-employed and landlords.

Step 5: Confirm Which Allowances Apply

Trading allowance (self-employment)

If your gross self-employment income for the year is likely to be £1,000 or less, you may be able to use the trading allowance instead of claiming individual expenses. You cannot use the trading allowance and also claim expenses - it is one or the other. If your income is higher than £1,000, you almost certainly benefit more from claiming actual expenses.

Property allowance (rental)

Similarly, if your gross rental income is £1,000 or less for the year, you can use the £1,000 property allowance rather than claiming individual expenses. Again, it is either the allowance or actual expenses - you cannot mix them. Most landlords with any meaningful costs will do better claiming actual expenses.

Capital allowances (self-employment)

If you bought equipment or tools for your business during Q1, you may be able to claim capital allowances. The Annual Investment Allowance lets most sole traders write off the full cost of qualifying equipment in the year of purchase. This is not something you normally include in a quarterly update - it typically forms part of your annual tax return - but keep the receipts and note the purchase now.

For more on what to claim in the August update specifically, see the post on Q1 allowances and adjustments for August 2026.

Step 6: Deal With Any Remaining Uncategorised Expenses

Most people have a few transactions sitting in their records with no category attached. Six weeks out is late enough that this pile should be small. Work through it now.

For each uncategorised item, ask:

1. Was it genuinely for the business or rental property?
2. If yes, which income stream does it belong to?
3. What is the correct expense category?
4. Do you have a receipt or evidence for it?

If you cannot answer yes to question 1, do not include it. Personal costs are not allowable, regardless of how the payment was made. If you paid for something personal from your business account, that is fine - just do not claim it.

If you have a larger problem with disorganised records, the post on fixing messy expense records before August covers a practical triage approach for getting things in order quickly.

You can also import a CSV of expenses into AffordableMTD and use the AI categorisation feature to help sort transactions faster. More on how that works in the post on importing Q1 expenses with CSV and AI categorisation.

Step 7: Run Your Final Spot-Checks

Before you finalise your figures, run through this checklist. These are the checks that catch errors before they become amendments.

Bank reconciliation

• Does your total recorded income match the money received in your bank between 6 April and 5 July?
• Have you checked all accounts - including PayPal, Stripe, or other payment processors?
• Have you accounted for payments made in cash?

Expense totals

• Do your total expenses look reasonable against your income?
• Is any single category unusually high compared to previous periods?
• Have you accidentally doubled up any transactions - particularly direct debits that show twice?

Documentation

• Do you have receipts or invoices for all claimed expenses?
• Are bank statements saved for the quarter?
• If you are claiming home office costs, do you have a calculation you can show?

HMRC does not require you to submit receipts with your quarterly update, but they can ask for them later. The post on preparing records for HMRC enquiries after Q1 explains what you should keep and for how long. For the record-keeping standards that apply specifically under MTD, see HMRC record-keeping standards for MTD compliance.

Step 8: Check the Difference Between a Quarterly Update and Your Tax Return

A quarterly update is not your tax return. It is a summary of income and expenses for the period. HMRC uses it to build a picture of your tax year, but you will not owe or receive tax based on your quarterly update alone. The final calculation happens at the end-of-year declaration.

This matters for reconciliation because it means you do not need to include everything at this stage. Adjustments like capital allowances, personal allowance, or pension contributions are handled at the year-end stage, not in the quarterly update.

The post on MTD quarterly updates versus a full tax return explains this clearly if you want more background before you file.

If Something Is Wrong: You Can Still Amend

If you spot an error in a figure you have already entered, you can correct it before you submit. If you have already submitted your Q1 quarterly update and then find an error, amendments are possible. The post on amending your Q1 MTD update before 7 August walks through how to do that step by step.

Do not ignore errors because amending feels complicated. A small correction now is far better than a discrepancy that flags your records for an HMRC enquiry later.

After You File: What Comes Next

Once you have submitted your Q1 quarterly update, Q2 begins immediately. The period from 6 July to 5 October 2026 is already under way, and good habits now will make that deadline easier. The post on Q2 MTD preparation is worth reading as soon as your Q1 update is done. You might also want to look at what to do after your Q1 filing to understand the full picture going forward.

Pulling It Together

With six weeks to go, the work you do this week is the most important of the whole quarter. Reconciling your profit and loss, separating your income streams, clearing uncategorised expenses, and confirming your allowances are the steps that turn messy records into a clean, accurate quarterly update. There is still time to get this right. The checklist above is your roadmap. Work through it section by section, and by the time you go to file, there should be no surprises.