Made a mistake after filing? Don’t worry — it happens to everyone! Whether you forgot to add an expense, entered the wrong rent amount, or categorized something incorrectly, the good news is that HMRC's MTD system is designed to handle corrections. Plus, RentalBux makes the whole process easy.
First — don't panic
An error in a quarterly update is different from a mistake on your final tax return. Quarterly updates are just estimates, so HMRC expects them to be refined over time. As long as you make corrections within the allowed time, they won’t automatically result in an investigation or penalty.
Amending a quarterly update
Document | What it is | Can you amend it? | How long do you have? |
|---|---|---|---|
Quarterly Update | Estimate of income and expenses for a 3-month period | Yes — unlimited amendments until the final tax declaration | Until the final tax declaration is submitted |
Final Declaration | Your overall tax position for the year | Yes — via amendment | Up to one year after 31 January following the tax year |
Quick Tip: You don't need to refile the entire quarter — RentalBux only sends the difference to HMRC. The amendment process is quick, usually under five minutes once you've made the underlying correction.
Common mistakes and how to fix them
Mistake | How to fix it |
|---|---|
Forgot to record an expense | Add the expense in Bills, assign it to the correct period, then resubmit the quarter |
Wrong income amount on a rent invoice | Edit the invoice amount, then resubmit the quarter |
Expense in the wrong category | Re-categorise the transaction, then resubmit |
Submitted the wrong tax year period | Contact HMRC directly — RentalBux can help you prepare the documentation |
Duplicate entry (same expense twice) | Delete the duplicate entry in Bills, then resubmit |
What to do if HMRC queries a submission
If HMRC contacts you about a figure in your quarterly update, don’t guess! Log in to RentalBux, go to the relevant quarter, and export a full transaction breakdown. This will show every invoice and expense that went into the summary — your complete audit trail.
Tip: Regular reconciliation (ideally monthly) is the best way to catch mistakes early, before they turn into bigger issues. The Bank Reconciliation feature in RentalBux makes it easy to stay on top of your numbers.