If you can’t pay your Self Assessment tax bill, file your return on time anyway and contact HMRC before the debt is 30 days overdue to set up a Time to Pay arrangement. That single step spreads the balance into monthly instalments and stops late payment penalties from being charged at all. Interest still runs from the day after the due date, but avoiding the penalty surcharges is the difference between a manageable plan and a debt that grows by 15% over a year of inaction.
File the Return Even If You Can’t Pay a Penny
Late filing and late payment are punished separately. Miss the filing deadline and HMRC charges a flat £100 straight away, even if you owe no tax. Miss the payment deadline and a completely different set of charges begins to build. Filing on time closes off one entire penalty track and is also what unlocks the online payment plan service, so submit the return whether or not you can settle the bill.1GOV.UK. Self Assessment Tax Returns – Penalties
What Late Payment Actually Costs
Once the tax is overdue, HMRC charges a 5% penalty on the unpaid amount at 30 days. Another 5% is added if any balance remains at six months, and a third 5% at twelve months. Over a full year of non-payment, that is 15% of the original debt in fixed penalties alone.1GOV.UK. Self Assessment Tax Returns – Penalties
Daily interest runs on top. Since 6 April 2025, the late payment interest rate is the Bank of England base rate plus 4%, up from base rate plus 2.5% under the previous formula. With a base rate of 3.75%, that puts the rate at 7.75% a year, and it moves whenever the Bank of England adjusts the base rate.2GOV.UK. HMRC Interest Rates for Late and Early Payments Interest compounds daily and applies alongside the percentage penalties, not instead of them.
Time to Pay: The 30-Day Window That Stops Penalties
The detail that matters most: if you agree a Time to Pay arrangement within 30 days of the payment due date, no late payment penalties are charged.3HM Revenue & Customs. Self Assessment Manual – SAM61380 Interest still applies from day one, but you eliminate the 5% surcharges at 30 days, six months, and twelve months. On a £10,000 debt, that is £500 saved immediately and potentially £1,500 saved if the debt would have run for a year. This is why picking up the phone or logging in quickly is worth more than any other single action.
Can You Set the Plan Up Online?
HMRC’s automated online service lets you agree a plan without speaking to anyone, provided you meet every one of these conditions:
- You owe £30,000 or less in Self Assessment.
- You have no other HMRC debts and no other active payment plan.
- All previous tax returns are filed.
- You apply within 60 days of the payment due date.
- You can clear the balance within 12 months.
If you owe more than £30,000, need longer than 12 months, or fail any other condition, you can still arrange a plan, but you have to call HMRC. Phone negotiations can produce longer repayment terms, though HMRC will review your income and outgoings in detail before agreeing.4GOV.UK. If You Cannot Pay Your Tax Bill on Time – Setting Up a Payment Plan
What to Have Ready Before You Apply
Whether you go online or call, gather these before you start:
- Your Unique Taxpayer Reference (UTR), a 10- or 13-digit number in your Personal Tax Account, the HMRC app, or on previous HMRC correspondence.5GOV.UK. Unique Taxpayer Reference – HMRC Patterns for Services
- Bank account details for a Direct Debit you are authorised to set up.
- A realistic figure for monthly disposable income: net income minus essential costs like housing, utilities, food, transport, and child maintenance. That surplus is the ceiling for your instalment.
- Details of any savings or liquid assets. HMRC will expect you to put those toward an upfront partial payment before spreading the rest.4GOV.UK. If You Cannot Pay Your Tax Bill on Time – Setting Up a Payment Plan
If you are calling, HMRC will also ask about other taxes you may owe and want a detailed breakdown of monthly spending. Honest, documented figures make approval more likely. Overstating what you can afford in order to seem cooperative usually backfires, because defaulting later is treated much more harshly than proposing a smaller sustainable payment at the outset.
How the Plan Works Once It’s Set Up
For the online route, sign in through the Government Gateway and open the payment plan option. The system confirms your eligibility, shows the balance, and lets you pick a monthly amount and start date. It then sets up the Direct Debit automatically, with the first collection landing within a few weeks.6GOV.UK. Pay Your Self Assessment Tax Bill
To arrange it by phone, call the Self Assessment payment helpline on 0300 200 3820. An adviser goes through your finances and agrees the amounts. Either way, HMRC sends a written confirmation listing every scheduled payment. Keep that, and make sure the money is in the account each month, because the Direct Debit will try to collect regardless of your balance.
Interest keeps accruing on the outstanding balance for the life of the plan, so the final instalment will be slightly larger than the remaining principal. That is normal.
If You Miss a Payment
Missing an instalment is not treated as a routine late payment. HMRC can cancel the arrangement entirely, at which point the whole remaining balance becomes immediately due and the late payment penalties that were suspended can be applied as though the plan had never existed. Defaulting quietly leaves you worse off than never having set up the plan.
If you can see a missed payment coming, call HMRC before the Direct Debit fails. They can often adjust the schedule instead of cancelling. What triggers the harshest response is silence.
Reduce Payments on Account to Shrink the Bill
The January bill is often not just the previous year’s tax. HMRC also collects “payments on account,” advance instalments toward the next year’s liability. Each one is half of your previous year’s tax, due on 31 January and 31 July. If last year’s bill was £4,000, HMRC expects two £2,000 payments on account on top of any balancing payment.7GOV.UK. Understand Your Self Assessment Tax Bill – Payments on Account
Payments on account don’t apply if your previous bill was under £1,000, or if more than 80% of your tax was already collected at source through your tax code.7GOV.UK. Understand Your Self Assessment Tax Bill – Payments on Account
If your income has dropped, you can apply to reduce your payments on account through your online account or by post. Doing so lowers the amount due immediately and may bring your total inside the £30,000 threshold for an online payment plan. Be accurate: if you reduce them too far, HMRC charges interest on the shortfall.8GOV.UK. Claim to Reduce Payments on Account
Breathing Space If the Problem Is Bigger Than One Bill
If tax is one debt among several you cannot manage, the Debt Respite Scheme (Breathing Space) offers a legal pause on creditor action. During a standard Breathing Space of up to 60 days, interest, penalties, and enforcement on qualifying debts are frozen, and tax debts are included.9GOV.UK. Debt Respite Scheme (Breathing Space) Guidance for Creditors
You have to live in England or Wales, get advice from an FCA-regulated debt adviser, and not have used Breathing Space in the previous twelve months. You also cannot be on a Debt Relief Order or an Individual Voluntary Arrangement. The 60 days is meant to give you time to arrange something longer-lasting, like a Time to Pay plan or a formal debt solution, and a midway review checks you are making progress. A separate Mental Health Crisis Breathing Space lasts for the duration of crisis treatment plus 30 days.
Reasonable Excuse Appeals: What They Are and Aren’t For
If a late payment penalty has already been charged and something genuinely beyond your control caused the delay, you can ask HMRC to cancel it by claiming a “reasonable excuse.” HMRC accepts things like serious or life-threatening illness, an unexpected hospital stay, a bereavement close to the deadline, a fire or flood, or delays caused by a disability or mental health condition.10GOV.UK. Reasonable Excuses
Not having the money is explicitly not a reasonable excuse. Neither is a bounced cheque, finding the online system confusing, not getting a reminder, or making a mistake on the return.10GOV.UK. Reasonable Excuses If your problem is affordability, the tool is a Time to Pay arrangement, not an appeal. If you do have a valid excuse, HMRC expects you to file or pay as soon as the obstacle passes.
What Happens If You Do Nothing
HMRC treats tax as a priority debt and has enforcement powers most creditors don’t. If you refuse to engage, HMRC can collect directly from your wages, bank account, or pension without a court order. They can instruct debt collection agencies, apply for a county court judgment, or in serious cases petition to make you bankrupt or wind up your business.1GOV.UK. Self Assessment Tax Returns – Penalties
The people who face those outcomes are almost always the ones who ignored letters for months. The system is set up to prefer agreed plans over enforcement, so early contact is what keeps every one of these options open.