Payments on Account: When HMRC Wants Tax Up Front

Introduction: The Bill Before You’ve Earned It

For the growing army of UK side hustlers—from Etsy sellers and Uber drivers to freelance consultants and buy-to-let landlords—entering the Self Assessment regime is a rite of passage.

It usually begins with a simple tax return and ends with a bill.

However, for many, the second year of trading brings a shock: a demand for tax that is significantly higher than expected.

This is the moment they encounter Payments on Account.

It is a mechanism designed to settle your tax liability in advance, based on the previous year's success.

It catches thousands of new business owners off guard, often turning a manageable £2,000 tax bill into a demanding £3,000 outlay overnight.

Understanding this system is not merely administrative; it is essential for cash flow survival.

What Are Payments on Account?

Payments on Account are advance payments towards your next year’s tax bill.

HMRC operates a system where tax is payable in two instalments during the year, rather than in a single lump sum at the end.

The logic is straightforward: HMRC does not want to wait 12 months to receive tax on profits earned earlier in the year.

By requiring you to pay in advance, they essentially smooth out the government's cash flow, ensuring they receive tax revenue on a current basis rather than always chasing arrears.

Each payment on account represents 50% of your previous year’s tax liability.

Therefore, if you owed £3,000 in tax for the 2023/24 tax year, HMRC assumes you will earn a similar amount in 2024/25.

They will ask for two payments of £1,500.

The first is due on 31 January (the same day your balancing payment for the previous year is due), and the second is due on 31 July.

This system applies specifically to Income Tax and Class 4 National Insurance contributions.

It does not apply to Student Loan repayments or Capital Gains Tax, which are settled separately via the balancing payment.

The Trigger: When Does This Start?

The most dangerous aspect of Payments on Account is the element of surprise.

You do not pay them in your first year of trading with a profit.

In year one, you simply pay the tax you owe by the 31 January deadline.

This lulls new side hustlers into a false sense of security.

The trap springs in the second year.

If your tax liability for the previous year exceeds a specific threshold, the Payments on Account mechanism activates automatically.

The threshold is £1,000.

If the tax you owe (after deducting tax deducted at source, such as PAYE, but before accounting for payments on account already made) is more than £1,000, you must make payments on account for the following year.

This means a side hustle that generates a modest profit can easily trigger the requirement.

For the 2024/25 tax year, the basic rate of Income Tax is 20%.

To cross the £1,000 tax threshold, you only need a taxable profit of roughly £5,000 above your Personal Allowance.

Once you cross this line, you are in the system.

The Financial Mechanics: Calculating the Cost

To navigate this system, you must understand the arithmetic.

Let us assume you have a side hustle designing websites.

In the 2023/24 tax year, your profits resulted in a tax and Class 4 National Insurance liability of £4,000.

You have no tax deducted at source.

Here is how the payment schedule unfolds:

By 31 July 2025, you have paid a total of £8,000.

When you eventually file your return for 2024/25, if your actual liability is exactly £4,000, you have nothing more to pay (your payments on account covered it).

If your liability is higher, say £5,000, you owe a balancing payment of £1,000 by 31 January 2026, plus new payments on account for 2025/26 based on the higher figure.

This compounding effect is why growing businesses often feel a permanent squeeze on their cash flow.

Strategies for Management and Mitigation

While you cannot simply ignore the rules if you owe the tax, there are legitimate strategies to manage the burden.

The first is strict financial hygiene.

A common rule of thumb is to set aside 25% to 30% of all side-hustle profits into a dedicated savings account.

This covers basic rate tax (20%) and Class 4 National Insurance (6% at the lower rate, 2% at the higher rate).

However, to handle Payments on Account, you must accelerate your saving.

You are not just saving for the tax on the work you just did; you are saving for the tax on the work you are about to do.

Claiming Allowable Expenses

The most effective way to reduce Payments on Account is to lower your taxable profit in the first place.

This requires a rigorous approach to claiming allowable expenses.

Many side hustlers under-claim because they are unsure what counts.

If you work from home, you can claim a proportion of heating, electricity, council tax, and mortgage interest (or rent) based on the number of rooms used for business and the amount of time spent working.

If you use your personal car for business travel—excluding commuting—you can claim mileage (45p per mile for the first 10,000 miles).

Lowering your profit lowers your tax bill, which in turn lowers the threshold for Payments on Account or reduces the instalment amounts.

The Trading Allowance Trade-off

For very small side hustles, the Trading Allowance offers a simple solution.

You can earn up to £1,000 from self-employment without reporting it to HMRC.

If your turnover is below this, you have no tax liability and no Payments on Account.

However, if your turnover is £1,200, you have a choice.

You can deduct the £1,000 allowance and pay tax on the £200 profit, or you can deduct actual expenses.

If your actual expenses are low, claiming the allowance is beneficial.

But if you have significant expenses (e.g., buying stock or equipment), deducting actual expenses might lower your profit further.

If your tax liability drops below £1,000, you exit the Payments on Account regime entirely.

When Your Income Drops: Claiming to Reduce

Payments on Account are calculated based on the previous year’s tax.

This is a backward-looking metric.

If your side hustle is seasonal, or if you decide to scale back to focus on your main employment, paying tax based on a previous bumper year is unfair and financially damaging.

HMRC recognises this and allows you to apply to reduce your Payments on Account.

You can apply to reduce these payments if you know your taxable profit for the current year will be lower than the previous year.

This is done via form SA303 or through your Government Gateway account.

You can reduce the payments to an amount you believe reflects your actual liability.

However, this requires estimation.

If you estimate that your tax bill will drop from £4,000 to £2,000, you can reduce your payments on account from £2,000 each to £1,000 each.

This facility carries a significant risk.

If you reduce your payments and it turns out your income was actually higher than estimated, HMRC will charge interest on the underpaid tax.

The interest rate on late tax is currently high (set at the Bank of England base rate plus 2.5%).

Therefore, you should only reduce payments if you have a reasonable certainty that your income has fallen.

Do not reduce payments simply to ease cash flow if you expect a late surge in business.

"Tax is ultimately payable on the profit actually earned in the year.

Payments on Account are merely an estimate.

If the estimate is wrong, it must be corrected.

It is better to pay a little too much during the year and receive a refund than to pay too little and face interest and penalties."

Interest, Penalties, and The Cost of Failure

Missing a Payment on Account deadline has immediate financial consequences.

HMRC charges interest on the unpaid amount from the date it was due until the date it is paid.

This is not a penalty, but a statutory interest charge.

As of late 2024, HMRC interest rates are significantly higher than commercial savings rates, making this an expensive loan.

If you miss the payment entirely, you may also face a 5% late payment penalty if the tax remains unpaid 30 days after the due date.

Further penalties accrue at 6 months and 12 months.

The system is automated and aggressive.

Unlike a commercial creditor, HMRC has the power to deduct tax directly from your wages or bank account via a Direct Recovery of Debts order if you owe more than £1,000 and ignore correspondence.

Checklist: Are You Ready for Payments on Account?

Use this checklist to determine if you need to prepare for advance tax payments this financial year:

• ✅ Your tax bill (excluding amounts deducted at source) was over £1,000 last year.

• ✅ You have filed your Self Assessment tax return for the previous tax year.

• ✅ You have calculated your profit for the current year to check if it has risen or fallen.

• ✅ You have set aside funds (approx. 50% of last year's tax bill) for the January payment.

• ✅ You have set aside funds for the July payment.

• ❌ You are not relying on the tax you owe from last year's profits to pay this year's advance.

• ❌ You have not ignored HMRC statements assuming they are errors.

Practical Scenarios for the Side Hustler

Scenario A: The Growing Freelancer

Sarah works full-time as a graphic designer and runs a freelance business on weekends.

In 2022/23, her side hustle profit was low, resulting in a tax bill of £800.

She paid this in January 2024.

Because she was under the £1,000 threshold, she paid no Payments on Account.

In 2023/24, she landed a major recurring contract.

Her profit jumped, resulting in a tax bill of £3,500.

On 31 January 2025, she must pay the £3,500 balancing payment.

However, because she crossed the threshold, she must also pay £1,750 on account for 2024/25.

Her total January bill is £5,250.

She must find an extra £1,750 she did not have to pay the previous year.

Scenario B: The Accidental Landlord

James rents out a flat.

His profit after allowable expenses (including mortgage interest relief, which is restricted to a 20% credit) results in a tax liability of £1,200.

He is now in the Payments on Account regime.

He pays £600 in January and £600 in July.

However, in the following year, his tenant leaves and the property sits empty for six months while he conducts repairs.

He knows his profit will be near zero.

He files form SA303 to reduce his Payments on Account to zero.

He avoids paying tax on income he did not earn, but he must ensure his return filed later reflects this low income to avoid interest charges.

Funding Options and Time to Pay

If you find yourself unable to meet the Payment on Account deadline, silence is your worst enemy.

HMRC offers a "Time to Pay" arrangement for those who cannot pay their tax bill in full.

This allows you to pay in instalments over a period.

However, you must contact HMRC before the payment is due, or as soon as possible after you realise you cannot pay.

Setting up a Time to Pay arrangement is not automatic.

You will need to provide details of your income and expenditure to prove you cannot pay.

Interest is still charged on the outstanding balance.

Generally, HMRC expects the debt to be cleared within 12 months.

If you owe less than £30,000, you can usually set up a payment plan online via the Government Gateway without speaking to an advisor.

If you owe more, or if you need longer than 12 months, you must call the Payment Support Service.

This is a viable safety net, but it should not be relied upon as a standard cash flow management tool.

Record Keeping: Your Only Defence

The complexity of Payments on Account makes rigorous record keeping non-negotiable.

You must maintain accurate records of all income and expenses.

This includes invoices, receipts, bank statements, and mileage logs.

Without these, you cannot accurately calculate your profit, which means you cannot estimate if your Payments on Account are correct.

If you overpay, you tie up capital unnecessarily; if you underpay, you risk interest and penalties.

Digital record keeping is now mandatory for many under the Making Tax Digital (MTD) for Income Tax rules (which are expanding to cover self-employed businesses and landlords with gross income over £50,000 from April 2026, and over £30,000 from April 2027).

Even if you are below these thresholds, using software such as Xero, QuickBooks, or FreeAgent allows you to run a "tax liability" report in real-time.

This report estimates your tax bill, including potential Payments on Account, allowing you to manage your savings pot with precision.

Conclusion

Payments on Account are a reality of the UK tax system for anyone with a successful side hustle.

They represent a shift from paying tax in arrears to paying in advance, a transition that causes financial friction in the second year of trading.

By understanding the £1,000 threshold, calculating the 50% instalments, and maintaining a disciplined savings buffer, you can navigate this system without panic.

Whether you choose to reduce your payments because of falling profits or simply budget for the extra cost, the key is proactive management.

Treat your tax liability as a monthly expense, not an annual surprise, and the demand for tax up front becomes a manageable part of doing business.