How Much Tax Should a Sole Trader Save Each Month in 2026/27?

That £5,000 sitting in your business bank account is not necessarily £5,000 you can spend.

For many sole traders, one of the biggest shocks comes when the Self Assessment tax bill arrives.

The business has been busy. Money has been coming in. However, nobody has been putting enough aside for tax.

Then January arrives.

Suddenly, a tax bill of several thousand pounds needs paying.

So how much tax should a sole trader actually save each month?

You may have heard people suggest saving 20%, 25% or even 30% of your income. However, the right amount depends on your profit, not simply the money entering your bank account.

This guide explains how Income Tax, National Insurance and payments on account can affect a sole trader in the 2026/27 tax year. We will also show you a simple way to build a tax-saving habit before the next bill arrives.

If you want help keeping your business records clear throughout the year, Real Key Accountancy provides straightforward bookkeeping support for sole traders and small businesses.

How much should a sole trader save for tax?

There is no single percentage that works for every sole trader.

However, many business owners use a percentage of their profit as a simple starting point.

A common approach is to consider putting around 25% to 30% of profit into a separate tax pot.

Importantly, this is only a budgeting rule of thumb. It is not an HMRC tax rate.

Your actual tax bill depends on factors such as:

• Your taxable business profit
• Other employment income
• Rental income
• Pension income
• Student loan repayments
• Allowances
• Previous tax payments
• Payments on account
• Whether you live in Scotland

Therefore, a 25% tax pot may be more than enough for one person but too little for another.

The first mistake: saving tax based on turnover

Turnover and profit are not the same thing.

This matters when deciding how much money to save.

Imagine your business receives £50,000 during the year.

You also have £15,000 of allowable business expenses.

Your starting business profit would be:

£50,000 turnover – £15,000 expenses = £35,000 profit

You would normally calculate your tax position using the profit rather than simply applying tax to the full £50,000 of sales.

That is one reason accurate bookkeeping matters.

Without clear records, you may not know your real profit.

Regular bookkeeping support from Real Key Accountancy can help you keep income and expenses organised throughout the year.

What is the Personal Allowance for 2026/27?

For the 2026/27 tax year, the standard Personal Allowance is £12,570.

This means you can normally receive up to £12,570 of income before paying Income Tax, although your circumstances can change the amount available.

The allowance begins to reduce when adjusted net income exceeds £100,000.

You can check the latest figures on the official HMRC Income Tax rates and Personal Allowances page.

Income Tax rates for sole traders in 2026/27

For most taxpayers in England, Wales and Northern Ireland, the 2026/27 Income Tax bands are:

However, Scotland uses different Income Tax bands for non-savings, non-dividend income.

Therefore, Scottish taxpayers should check the rates that apply to them rather than relying on the examples below.

Do sole traders also pay National Insurance?

Yes, many sole traders also pay Class 4 National Insurance based on their profits.

For 2026/27, the main Class 4 rate is:

• 6% on profits between £12,570 and £50,270
• 2% on profits above £50,270

Therefore, your tax pot needs to consider more than Income Tax alone.

This is another reason why simply saying “I pay 20% tax” can be misleading for a sole trader.

How much tax could you pay on £25,000 profit?

Let us look at a simple example.

Assume:

• You are a sole trader
• Your annual profit is £25,000
• You live in England, Wales or Northern Ireland
• You have the standard Personal Allowance
• You have no other taxable income
• No student loan applies

After the £12,570 Personal Allowance, approximately £12,430 remains subject to basic-rate Income Tax.

Income Tax would therefore be around:

£12,430 × 20% = £2,486

Class 4 National Insurance would add approximately:

£745.80

That gives an illustrative total of around:

£3,231.80

This equals roughly 12.9% of the £25,000 profit.

Therefore, putting 25% aside in this simple example would create a useful buffer.

However, your real bill can differ.

How much tax could you pay on £40,000 profit?

Now imagine your annual sole trader profit reaches £40,000.

Using the same simple assumptions:

• Approximate Income Tax: £5,486
• Approximate Class 4 National Insurance: £1,645.80

Total:

Approximately £7,131.80

That represents around 17.8% of profit.

Again, a 25% saving pot could provide some room for payments on account or changes in your circumstances.

What about £60,000 of sole trader profit?

At £60,000 of profit, part of your taxable income reaches the higher-rate band.

Using the same assumptions, an illustrative calculation gives:

• Approximate Income Tax: £11,432
• Approximate Class 4 National Insurance: £2,456.60

Total:

Approximately £13,888.60

That is around 23.1% of the £60,000 profit.

Therefore, as profits increase, the percentage you need to reserve can also increase.

Why saving 25% is not always enough

A 25% tax pot sounds generous when your profit is relatively modest.

However, several things can increase your final bill.

You have another job

If you also receive PAYE employment income, your salary may already use some or all of your Personal Allowance.

As a result, more of your self-employed profit may become taxable.

You have rental income

Property income may also affect your overall taxable income.

Therefore, do not calculate your business tax pot in isolation if you have other significant income.

You have a student loan

Self Assessment can also calculate student loan repayments when they apply.

This can increase the amount due in January.

Your profits have increased quickly

A business can move into higher tax rates faster than the owner expects.

For example, a sole trader who grows from £30,000 to £70,000 profit may need a very different tax-saving strategy.

You have payments on account

This is one of the biggest causes of January tax-bill shock.

What are payments on account?

Payments on account are advance payments towards your next Self Assessment tax bill.

HMRC normally asks for two payments when the rules apply.

The usual deadlines are:

• 31 January – first payment on account
• 31 July – second payment on account

Each payment is normally half of the relevant previous year’s tax bill.

You usually do not need payments on account if your relevant previous Self Assessment tax was below £1,000 or if more than 80% of the tax was collected outside Self Assessment.

You can read the official HMRC payments on account guidance.

The January bill that catches new sole traders out

Imagine your tax calculation shows £6,000 due for your first significant year of self-employment.

You might expect January’s payment to be:

£6,000

However, if payments on account apply, you could also face a first advance payment towards the following year.

If that payment were £3,000, your January cash requirement could become:

£9,000

Then another payment could fall due in July.

This is why simply saving enough for the estimated current-year tax may not always be enough.

A simple tax-saving system for sole traders

You do not need a complicated spreadsheet to start building a tax pot.

Instead, use a simple routine.

Step 1: Use a separate savings account

Create a separate account or savings pot specifically for tax.

Do not use this money for normal business spending.

Separating the money can reduce the temptation to spend it.

Step 2: Review your profit every month

Do not base your tax savings only on sales.

Instead, review:

• Income
• Allowable business expenses
• Estimated profit
• Other income

Good bookkeeping makes this much easier.

Step 3: Transfer money every month

Do not wait until January.

For example, if you decide that 25% is an appropriate starting reserve, move that amount into the tax account as part of your monthly routine.

This turns tax into a regular business cost rather than an annual emergency.

Step 4: Increase the percentage when profit grows

Your tax position changes as your profit increases.

Therefore, review the percentage rather than using the same figure forever.

Step 5: Check your position before year end

A proper review can tell you whether your tax pot looks realistic.

This gives you time to correct the amount before the bill becomes due.

Monthly example: £4,000 profit

Imagine your business makes £4,000 of profit in a month.

If you use a simple 25% reserve:

£4,000 × 25% = £1,000

You would transfer £1,000 into your tax savings account.

You would then have £3,000 remaining before other commitments and drawings.

Again, this is a budgeting method rather than an exact tax calculation.

However, it can create a much healthier habit than putting nothing aside.

Should you save tax every week instead?

You can.

In fact, weekly saving can work particularly well for:

• Taxi drivers
• Tradespeople
• Delivery drivers
• Freelancers
• Hairdressers
• Beauty professionals
• Consultants
• Other businesses with regular weekly income

For example, if your weekly profit is £800 and you choose a 25% reserve:

£800 × 25% = £200

You would transfer £200 to your tax pot.

Small, regular transfers can feel much easier than finding several thousand pounds in January.

What business expenses can reduce your taxable profit?

Allowable business expenses can reduce the profit on which you calculate tax.

Depending on your business, these may include eligible costs such as:

• Office costs
• Business travel
• Stock and materials
• Software
• Business phone costs
• Advertising
• Professional fees
• Insurance
• Some financial costs

However, you should only claim costs that meet the relevant rules.

HMRC says self-employed people should keep records of their business income and expenses.

You can read the official HMRC record-keeping guidance.

If you struggle to keep receipts, bank transactions and expenses organised, Real Key Accountancy can help you maintain clearer bookkeeping records.

Do you need to keep receipts?

You should keep suitable records that support your business transactions.

These may include:

• Receipts
• Invoices
• Bank statements
• Purchase records
• Sales records
• Payment-platform records

You do not normally send all these records to HMRC when you file the tax return.

However, HMRC can ask you to show evidence.

You can also read HMRC’s guidance on claiming self-employed expenses.

Making Tax Digital makes regular bookkeeping even more important

Making Tax Digital for Income Tax started for the first group of qualifying taxpayers from 6 April 2026.

Affected taxpayers need to keep digital records of relevant income and expenses using compatible software.

Therefore, leaving a year’s bookkeeping until January is becoming less practical for many sole traders.

HMRC explains the requirements in its Making Tax Digital digital-record guidance.

7 signs your tax savings may be too low

Ask yourself whether any of these sound familiar:

1. You spend almost everything that enters the business account.
2. You do not have a separate tax pot.
3. You do not know your current profit.
4. You only look at your bookkeeping near January.
5. You have never checked whether payments on account apply.
6. Your profit has increased significantly this year.
7. You are relying on last year’s tax bill as your estimate.

If several apply, it may be worth reviewing your tax savings now rather than waiting for the deadline.

5 bookkeeping habits that make tax easier

1. Record transactions regularly

Weekly or monthly bookkeeping reduces the size of the backlog.

2. Upload receipts immediately

A receipt is much easier to identify today than nine months later.

3. Keep business spending separate

A separate business account makes your records easier to understand.

4. Reconcile your bank account

Regular bank reconciliation can identify missing or duplicate transactions.

5. Review your Profit and Loss report

Your Profit and Loss report can help you understand whether your business is actually profitable.

That information can also help you make a more informed tax-saving decision.

When is the Self Assessment payment deadline?

For the 2025/26 tax return, most online returns must reach HMRC by 31 January 2027.

You also normally need to pay the tax due by the same date.

If payments on account apply, the second payment normally falls due on 31 July.

You can check the current dates on the HMRC Self Assessment deadlines page.

Can you pay your tax bill monthly?

You can choose to make regular payments towards a future Self Assessment bill.

HMRC offers a Budget Payment Plan for eligible taxpayers who are up to date with their previous Self Assessment payments.

This allows weekly or monthly Direct Debit payments towards the next bill.

You can read more about HMRC weekly and monthly Self Assessment payments.

Even if you do not use HMRC’s plan, keeping your own tax savings account can help you budget throughout the year.

So, should a sole trader save 20%, 25% or 30%?

Here is the simple answer.

Do not choose a percentage blindly.

For some sole traders, 20% may create enough money.

For others, 25% may provide a comfortable reserve.

Meanwhile, people with higher profits, other income, student loans or large payments on account may need 30% or more.

Therefore, start with an estimate but review it against your actual profit and circumstances.

The most important number is not your bank balance

It is easy to open your banking app and think:

“I’ve got £10,000 in the bank. Business is going well.”

However, some of that money may already belong to:

• HMRC
• Suppliers
• Employees
• VAT
• Upcoming business costs

The number that matters is what remains after your commitments.

Good bookkeeping helps you see that much more clearly.

How Real Key Accountancy can help

You should not have to guess how your business is performing.

Real Key Accountancy provides straightforward bookkeeping support for sole traders and small businesses.

We can help you:

• Keep bookkeeping up to date
• Record income and expenses
• Process bank transactions
• Reconcile your bank account
• Organise financial records
• Produce simple bookkeeping reports

Clearer records can make it easier to understand your profit and prepare for future tax bills.

If you want to discuss your bookkeeping, contact Real Key Accountancy to arrange a free 15-minute accounts review.

Frequently Asked Questions

How much tax should a sole trader put aside?

There is no single percentage that suits every sole trader. Some business owners use 25% to 30% of profit as a budgeting starting point, but your actual requirement depends on your profit, other income and personal circumstances.

Should I save tax based on turnover or profit?

Your taxable business profit is more relevant than turnover alone because allowable business expenses can reduce the amount of profit subject to tax.

Is 20% enough to save for Self Assessment?

It may be enough for some people, but not everyone. National Insurance, higher-rate tax, student loans and payments on account can increase the final amount due.

Is saving 30% for tax too much?

Not necessarily. Some sole traders deliberately keep a larger reserve to cover tax and payments on account. Any money left after the final calculation remains yours.

Do sole traders pay National Insurance?

Many sole traders pay Class 4 National Insurance when profits exceed the relevant threshold. For 2026/27, the main rate is 6% between the Lower and Upper Profits Limits and 2% above the Upper Profits Limit.

What are payments on account?

Payments on account are advance payments towards your next Self Assessment bill. HMRC normally asks for two instalments when the rules apply.

Can I pay Self Assessment every month?

You can make regular payments towards a future tax bill. Eligible taxpayers can also use HMRC’s Budget Payment Plan to make weekly or monthly payments.

Why does bookkeeping matter for tax?

Accurate bookkeeping helps you understand your income, expenses and profit. This gives you better information when estimating how much money to reserve for tax.

Can Real Key Accountancy help with my bookkeeping?

Yes. Real Key Accountancy provides bookkeeping support for sole traders and small businesses. Visit Real Key Accountancy or contact us to discuss the support available.

This article provides general information only and is not personalised accounting, tax or financial advice. The examples are simplified illustrations and do not include every possible allowance, deduction, student loan, other income or individual circumstance.