How to Contact HMRC about Simple Assessment?
- MAZ
- Feb 18
- 13 min read
Understanding Simple Assessment
Simple Assessment is one of those things that can catch UK taxpayers off guard. If you've received a letter from HM Revenue & Customs (HMRC) about this, you’re probably wondering: What exactly is it? Why am I being assessed this way? And most importantly, how do I contact HMRC about it?
Audio Summary of the Most Important Points of the Article:
What is Simple Assessment?
Simple Assessment is a system used by HMRC to calculate tax liabilities for certain taxpayers without requiring them to submit a Self Assessment tax return. Instead, HMRC does the math for you and sends you a tax calculation letter.
Who Receives a Simple Assessment Notice?
You may receive a Simple Assessment letter if you:
✔ Owe Income Tax that cannot be automatically deducted through PAYE (e.g., if you have multiple income sources).
✔ Owe HMRC £3,000 or more at the end of the tax year.
✔ Receive State Pension that exceeds your Personal Allowance, meaning tax cannot be deducted at source.
✔ Have other untaxed income, like rental earnings or freelance income, but are not required to file a full Self Assessment tax return.
The key difference between Self Assessment and Simple Assessment is that you do not need to submit a tax return—HMRC calculates everything for you.
Why You Might Need to Contact HMRC About Simple Assessment
While the system is designed to make tax payments easier, errors can happen. If you get a Simple Assessment letter, you may need to contact HMRC in the following situations:
1. You Think the Calculation is Incorrect
If you believe HMRC has miscalculated your tax liability, you have 60 days from the date of the letter to dispute it. Common errors include:
Income being overstated or understated.
Incorrect application of tax-free allowances.
HMRC failing to include deductible expenses.
2. You Haven’t Received a Simple Assessment But Think You Should Have
If you expected to receive a Simple Assessment but haven’t, you might need to contact HMRC to clarify your tax situation. This could be due to:
A delay in HMRC processing your details.
Your income sources changing, making you eligible for Simple Assessment.
3. You Need to Change Your Personal Details
If your address, name, or bank details have changed, you must inform HMRC to ensure you receive accurate tax calculations and avoid missed payments.
4. You Can’t Pay the Tax Bill on Time
If you cannot pay your Simple Assessment bill in full, contact HMRC before the due date to discuss a payment plan. HMRC may allow you to pay in instalments if you can prove financial hardship.
How to Contact HMRC About Simple Assessment?
Now that we’ve covered why you might need to reach out, let's go over the ways you can contact HMRC.
Contact Method | Best For | How to Access |
Phone Call | Urgent issues, tax disputes, or setting up a payment plan. | Call 0300 200 3300 (UK) or +44 135 535 9022 (outside the UK). Open Mon-Fri: 8am-6pm. |
Online Services | Checking your tax bill, disputing a calculation, or updating details. | Sign in to your Personal Tax Account here. |
Webchat | General queries and non-urgent support. | Available on HMRC’s website. |
Post | Sending formal disputes or providing supporting documents. | Write to: HMRC, BX9 1AS, United Kingdom. |
Note: HMRC does not provide a direct email address for Simple Assessment inquiries.
Calling HMRC: What You’ll Need
When calling HMRC, be prepared to provide:
✔ Your National Insurance number
✔ Your Simple Assessment reference number (found on the letter)
✔ Details of your income and any errors in the calculation\
Using HMRC’s Online Services
For many people, using their Personal Tax Account is the easiest way to manage their tax affairs. Here’s how:
Go to HMRC’s Personal Tax Account
Log in using your Government Gateway ID
Click on “Simple Assessment” to view details or raise a dispute
Deadlines for Payment & Disputes
It’s crucial to keep track of the deadlines.
Action | Deadline |
Disputing a Simple Assessment calculation | Within 60 days of receiving the letter |
Paying the tax bill (if received before 31 Oct 2024) | 31 Jan 2025 |
Paying the tax bill (if received after 31 Oct 2024) | Within 3 months of letter date |
What Happens After You Contact HMRC About Simple Assessment?
Once you reach out to HMRC, the process varies depending on the reason for your inquiry. Here’s what to expect based on your situation:
1. If You Dispute the Simple Assessment Calculation
If you believe HMRC has miscalculated your tax, you must challenge it within 60 days of receiving the letter.
Step 1: Contact HMRC by phone or online.
Step 2: Provide your Simple Assessment reference number (found on the letter).
Step 3: Explain the mistake and provide any supporting documents (such as P60s, P45s, or pension statements).
Step 4: HMRC will review the case, which can take several weeks.
Step 5: If HMRC agrees with you, they’ll issue a new calculation or cancel the assessment.
💡 Example: Suppose you received a Simple Assessment letter stating that you owe £4,500, but your personal records show that your income was lower than what HMRC calculated. You call HMRC, provide your P60 (which shows your total income), and they verify the mistake. If correct, HMRC will send you a revised bill with the correct amount.
2. If You Need to Set Up a Payment Plan
If you can’t afford to pay the tax in full, HMRC may offer a Time to Pay (TTP) arrangement.
Step 1: Call 0300 200 3822 (HMRC’s Payment Support Service).
Step 2: Provide your National Insurance number and details of your finances.
Step 3: HMRC may ask for your monthly income, expenses, and savings.
Step 4: If approved, you’ll set up a direct debit payment plan to pay in instalments.
📌 Key Fact: HMRC expects you to use any savings you have to reduce the debt before they agree to a payment plan.
3. If HMRC Rejects Your Dispute
If HMRC disagrees with your dispute, they will:
Send you a written explanation of why they believe their calculation is correct.
Give you an option to appeal further through an independent review or tribunal.
At this stage, you can:
✔ Request a Statutory Review (an independent HMRC officer will re-evaluate your case).
✔ Take your case to a tax tribunal if you still disagree with HMRC’s decision.
🚨 Warning: Taking a case to a tax tribunal can be time-consuming and may involve legal fees, so it’s best to resolve disputes directly with HMRC whenever possible.
Most Common Mistakes Taxpayers Make with Simple Assessment
Many UK taxpayers unknowingly make mistakes when dealing with HMRC’s Simple Assessment. Here are the most common errors and how to avoid them:
1. Missing the 60-Day Dispute Deadline
Problem: Many taxpayers realise too late that they had an error in their Simple Assessment.
Solution: Always check your tax letter immediately and set a reminder for the 60-day deadline.
2. Not Checking HMRC’s Calculation Properly
Problem: Assuming that HMRC’s figures are always correct.
Solution: Always compare HMRC’s tax bill with your:
✔ P60/P45 (if you’re employed)
✔ Pension statements (if you receive State Pension)
✔ Bank statements (if you have untaxed income)
3. Ignoring the Payment Deadline
Problem: Some taxpayers forget about their tax bill until it's too late, leading to penalties.
Solution: Mark your calendar with key deadlines:
If you received your Simple Assessment letter... | You must pay by... |
Before 31 October 2024 (for tax year 2023-24) | 31 January 2025 |
On or after 31 October 2024 | Within 3 months |
❗ Late payment penalties:
5% of unpaid tax if you miss the deadline by 30 days.
An additional 5% after 6 months.
Interest charged daily on outstanding tax.
4. Failing to Inform HMRC of Address Changes
Problem: If you move house and forget to update your address, you might miss important HMRC letters.
Solution: Update your address through your Personal Tax Account here or by calling 0300 200 3300.
5. Assuming HMRC Will Contact You If You Owe Tax
Problem: Some taxpayers don’t realise they owe tax until they receive a penalty letter.
Solution: Always check your Personal Tax Account regularly to see if HMRC has issued a tax bill.
How to Efficiently Resolve Simple Assessment Disputes
If you’ve received a wrong tax bill and need to correct it, follow these steps to speed up the resolution process:
Step 1: Gather All Necessary Documents
Before contacting HMRC, make sure you have:
✔ Your Simple Assessment letter
✔ Proof of income (P60, P45, pension statements, self-employment records)
✔ Bank statements showing tax payments (if applicable)
✔ Any previous HMRC correspondence
Step 2: Choose the Right Contact Method
For urgent issues, call HMRC directly. For non-urgent queries, use webchat or the online portal.
Method | Best For | Contact Details |
Phone Call | Urgent disputes, payment plans, and tax queries | 0300 200 3300 (Mon-Fri, 8am-6pm) |
Webchat | Non-urgent tax disputes, general tax questions | |
Personal Tax Account | Checking Simple Assessment details | Sign in here |
Post | Sending formal disputes and documents | HMRC, BX9 1AS, UK |
Step 3: Follow Up with HMRC
If HMRC doesn’t respond within 6 weeks, call them for an update.
✅ Pro Tip: If calling HMRC, do it early in the morning (8am-9am) or late afternoon (4pm-6pm) to avoid long wait times.
How to Avoid Getting a Simple Assessment in the Future
While Simple Assessment is meant to simplify tax payments, it can catch people off guard. Here’s how to avoid receiving one in the future:
1. Ensure Tax Is Deducted at Source Where Possible
If you're employed or receive a private pension, your tax is deducted via PAYE (Pay As You Earn).
If you have other income (e.g., rental or self-employment income), adjust your PAYE tax code to cover it.
✅ How to do this: Update your tax code through your Personal Tax Account here.
2. Check if You Should Register for Self Assessment Instead
Some people receive a Simple Assessment when they should actually file a Self Assessment tax return.
If you regularly earn income outside of PAYE, registering for Self Assessment may prevent unexpected tax bills.
Register before 5 October 2025 if you expect to owe tax for the 2024-25 tax year.
📌 Who should file a Self Assessment instead of relying on Simple Assessment?✔ Self-employed individuals earning over £1,000 per year✔ Landlords earning over £2,500 from rental income✔ Those with significant dividends or foreign income
3. Pay Any Owed Tax Before HMRC Issues a Simple Assessment
If you know you have extra tax to pay (e.g., from freelance work, rental income, or a pension shortfall), you can make a voluntary payment before HMRC issues a Simple Assessment.
This prevents HMRC from issuing an automatic tax bill.
✅ How to do this: Pay directly through HMRC’s online payment portal here.
When Can HMRC Take Enforcement Action for Unpaid Simple Assessment Tax?
If you ignore a Simple Assessment tax bill, HMRC has several ways to recover the money.
Time Since Missed Payment | Penalty / Action |
1 day late | Interest begins accruing (currently 7.75% per year as of Jan 2025). |
30 days late | 5% penalty on the unpaid amount. |
6 months late | Another 5% penalty added. |
12 months late | A further 5% penalty, plus potential debt collection. |
Over 12 months | HMRC can take legal action, use bailiffs, or deduct tax from your wages. |
❌ Warning: If HMRC believes you're deliberately avoiding tax, they can issue fines up to 100% of the unpaid tax.
Final Steps to Stay Tax-Compliant
1. Keep Your Personal Tax Account Updated
Your Personal Tax Account allows you to check tax bills, update information, and dispute assessments.
Sign in regularly to check if HMRC has issued any unexpected tax bills.
🔗 Sign in to your account here: HMRC Personal Tax Account
2. Double-Check Tax Codes and Allowances
Your tax code determines how much tax is deducted. If it's wrong, you might owe extra tax at the end of the year.
If your circumstances change (e.g., you retire, get a pay rise, or receive rental income), update HMRC immediately.
3. Set Payment Reminders
HMRC won’t always send reminders before penalties start accruing.
Set calendar alerts for key tax deadlines.
Key Deadline | What It’s For |
31 January 2025 | Payment deadline for most Simple Assessments for 2023-24. |
5 October 2025 | Deadline to register for Self Assessment if needed. |
4. Always Check Letters from HMRC
HMRC often sends letters instead of emails, so always open and read anything from them.
If you don’t receive expected letters, check your online tax account.
Simple Assessment can be confusing, but with proactive tax management, you can avoid surprises and unnecessary penalties. If you ever receive a tax bill you don’t understand, don’t ignore it—contact HMRC as soon as possible to resolve it.
Summary of All the Most Important Points Mentioned In the Above Article
Simple Assessment is an HMRC system that calculates tax liability for certain taxpayers without requiring them to file a Self Assessment tax return.
You may receive a Simple Assessment if you owe over £3,000 in tax, have untaxed income, or receive a State Pension exceeding the Personal Allowance.
If you believe your Simple Assessment tax calculation is incorrect, you must contact HMRC within 60 days to dispute it.
HMRC can be contacted about Simple Assessment via phone (0300 200 3300), online through the Personal Tax Account, webchat, or by post.
If you cannot pay your Simple Assessment tax bill in full, you can request a Time to Pay arrangement to spread the cost.
Ignoring a Simple Assessment bill can lead to penalties, interest charges, and HMRC enforcement actions, including legal proceedings or wage deductions.
Common taxpayer mistakes include missing dispute deadlines, assuming HMRC’s calculations are always correct, and failing to update personal details with HMRC.
To avoid receiving a Simple Assessment in the future, ensure tax is deducted at source or register for Self Assessment if necessary.
Late payment penalties include a 5% charge after 30 days, an additional 5% after six months, and further interest charges.
Regularly checking your Personal Tax Account and keeping tax records updated can help you avoid unexpected tax bills and compliance issues.
FAQs
Q1: Can you request a copy of your Simple Assessment letter if you lost the original?
A: Yes, you can request a duplicate Simple Assessment letter by calling HMRC at 0300 200 3300. You may need to provide your National Insurance number and other personal details for verification.
Q2: Can you check your Simple Assessment tax bill online?
A: No, as of September 2024, HMRC does not provide a direct online view of your Simple Assessment bill. You must refer to the physical letter sent by HMRC or contact them for details.
Q3: What happens if you ignore a Simple Assessment letter?
A: Ignoring a Simple Assessment letter can result in penalties, interest charges, and enforcement action. HMRC may take legal action or use debt collection agencies to recover unpaid tax.
Q4: Can you dispute a Simple Assessment tax bill after the 60-day deadline?
A: Yes, but only in exceptional circumstances. You must provide a valid reason for the delay, such as illness or missing correspondence. HMRC will decide whether to allow a late dispute.
Q5: Can you pay your Simple Assessment tax bill in cash?
A: No, HMRC does not accept cash payments for Simple Assessment tax bills. You can pay via bank transfer, cheque, or online payment methods.
Q6: What should you do if you receive a Simple Assessment letter for someone who has died?
A: If the taxpayer has passed away, their executor or administrator must contact HMRC’s bereavement helpline at 0300 200 3300 to update the records and settle any outstanding tax.
Q7: Can HMRC change your Simple Assessment tax bill after it has been issued?
A: Yes, HMRC can recalculate your tax if they discover an error or if you provide additional income details. They will issue a revised Simple Assessment letter if necessary.
Q8: How long does it take for HMRC to process a dispute on a Simple Assessment?
A: It typically takes 6-8 weeks for HMRC to review and respond to disputes, but complex cases may take longer. If you haven’t heard back, follow up with HMRC.
Q9: Can you cancel a Simple Assessment if you believe it was issued in error?
A: Yes, if you believe you should not have received a Simple Assessment, you can contact HMRC and provide supporting evidence. They may cancel the assessment if justified.
Q10: Can you request an extension on the payment deadline for a Simple Assessment tax bill?
A: HMRC generally does not grant extensions, but you can apply for a Time to Pay arrangement to spread the cost over multiple months if you’re struggling financially.
Q11: Do pensioners need to pay Simple Assessment tax bills manually?
A: Yes, pensioners who receive a Simple Assessment must pay their tax manually unless they have arranged tax deductions through PAYE.
Q12: Can you transfer your Simple Assessment tax liability to another person?
A: No, your tax liability is personal and cannot be transferred. However, if HMRC made an error in assigning the tax to you instead of another taxpayer, contact them immediately.
Q13: Does receiving a Simple Assessment mean you need to file a Self Assessment tax return?
A: No, Simple Assessment replaces the need for a Self Assessment tax return for certain taxpayers. However, if your financial situation changes, you may need to register for Self Assessment.
Q14: What should you do if your Simple Assessment letter is missing key details or amounts?
A: Contact HMRC at 0300 200 3300 and request a clarification. Have your National Insurance number ready for verification.
Q15: Will HMRC send reminders about unpaid Simple Assessment tax bills?
A: No, HMRC does not always send reminders. You are responsible for ensuring payment by the deadline stated in the letter.
Q16: Can you appeal a Simple Assessment tax bill in court?
A: Yes, if HMRC rejects your dispute, you can escalate the case to the First-tier Tax Tribunal. You may need legal advice before proceeding.
Q17: How do you update your address with HMRC to avoid missing a Simple Assessment letter?
A: You can update your address through your Personal Tax Account online or by calling HMRC. It’s important to keep your details updated to avoid missing tax notices.
Q18: Will unpaid Simple Assessment tax affect your credit score?
A: No, unpaid tax does not directly impact your credit score, but HMRC can take legal action, which may result in court judgments that could affect your financial record.
Q19: Can you request a breakdown of how HMRC calculated your Simple Assessment tax bill?
A: Yes, you can ask HMRC for a detailed breakdown if you do not understand how your tax was calculated. Contact them via phone or post for an explanation.
Q20: Can you pay a Simple Assessment tax bill using a credit card?
A: No, HMRC no longer accepts credit card payments for tax bills. You must use debit cards, bank transfers, or cheques instead.
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