What If I Made a Mistake on My Tax Return?

Don't Panic, Mistakes Happen

Discovered an error on your submitted tax return? You're not alone. HMRC receives thousands of corrections every year, and they have clear processes for fixing mistakes.

Types of Tax Return Mistakes

Minor Errors (Under £10,000 difference)

• Forgotten bank interest
• Small expense miscalculations
• Incorrect dates

Major Errors (Over £10,000 or significant omissions)

• Unreported rental income
• Missing employment income
• Substantial expense errors

How to Correct Your Tax Return

Option 1: Online Amendment (Simplest)

• Log in to your Government Gateway account
• Select "View and amend return"
• Make corrections and resubmit
• Available until 12 months after the original deadline

Option 2: Contact HMRC Directly

• Call the Self-Assessment helpline: 0300 200 3310
• Explain the error clearly
• Provide supporting documentation
• Get a reference number for your records

Option 3: Professional Help
For complex errors or if you're unsure about the correction process, professional accountants can:

• Review your entire return for other potential issues
• Handle all HMRC communication
• Ensure corrections are made properly
• Provide peace of mind

Will I Face Penalties?

HMRC distinguishes between:

• Innocent Mistakes: Usually no penalty if you correct them promptly and honestly.
• Careless Errors: Penalties of 0-30% of additional tax owed.
• Deliberate Errors: Penalties of 20-70% of additional tax owed.

Timeline for Corrections

• Immediately: Best time to correct - shows good faith
• Within 12 months: Can amend online easily
• After 12 months: Must contact HMRC directly
• After 4 years: HMRC may not accept corrections unless exceptional circumstances

Prevention is Better Than Correction
At Nunns Accounting, we prevent mistakes through:

• Thorough initial reviews
• Client questionnaires covering all income sources
• Regular check-ins throughout the tax year
• Professional software that flags potential errors

Enquire Here