Side-Hustle Tax Calculator
The AbraTax side-hustle tax calculator estimates additional Income Tax and National Insurance on entered extra income and shows a possible first January payment total under the stated assumptions.
Who This Calculator Is For
This calculator is for:
- Employees who sell goods or services alongside their day job
- Gig economy workers, including delivery drivers and task-based platform workers
- Creatives and freelancers with occasional project income
- Anyone whose hobby has started to become a business
- People considering whether they may need to register for Self Assessment
What You Need to Know
The Trading Allowance
If total gross trading income is £1,000 or less in a tax year, it may not need to be declared or taxed, although exceptions apply. Above £1,000, the current HMRC registration and reporting rules apply.
The trading allowance may be used instead of actual expenses when the eligibility conditions are met; both cannot be claimed against the same income. The calculator applies the option selected but does not determine which deduction is available or which treatment should be used.
How Your Side Income Is Taxed
Your side-hustle profit is added to your total income. The examples below use England, Wales, and Northern Ireland rates; Scottish non-savings Income Tax bands and rates differ:
- If total income stays within the basic-rate band, side-hustle profit may be taxed at 20%
- If it takes you into the higher-rate band, some or all of the profit may be taxed at 40%
Because your employer may already have used your Personal Allowance through PAYE, even modest side-hustle income can attract tax at the marginal rate applying to your highest slice of income.
National Insurance for the Self-Employed
For 2025/26 and 2026/27, Class 4 National Insurance is charged at 6% on self-employed profits between £12,570 and £50,270, and 2% above that. It is separate from the Class 1 National Insurance you may pay through employment.
How to Use the Side-Hustle Tax Calculator
- Select the tax year and where you live.
- Enter gross employment income and the Income Tax already paid through PAYE.
- Enter gross side-hustle income before expenses.
- Select the £1,000 trading allowance or actual-expenses option to choose which illustration is shown.
- The calculator will estimate additional Income Tax, Class 4 National Insurance, and payments on account.
Frequently Asked Questions
Do I need to register for Self Assessment if I only earned a small amount?
If total trading income before expenses exceeded £1,000 in the tax year, you will usually need to tell HMRC, subject to the trading allowance rules and any exceptions. The registration deadline is normally 5 October following the end of the tax year in which you first needed to report the income. This calculator estimates tax but does not decide whether an activity is trading or whether registration is required.
What if I sell things I already own, like old clothes or furniture?
Selling personal possessions is generally not trading and is not subject to Income Tax. If you regularly buy items intending to sell them at a profit, HMRC may treat the activity as trading.
Does platform income count?
Income from selling on platforms or working through apps can be taxable in the same way as other self-employment income. UK digital platforms have reporting obligations, but a platform report does not by itself decide whether you owe tax.
How are expenses treated?
Costs incurred wholly and exclusively for a trade may be deductible, subject to the relevant rules. Examples can include materials, equipment, packaging, platform fees, advertising, and an allowable proportion of home-working costs. The calculator treats entered expenses as allowable and does not determine entitlement.
Do I pay National Insurance on side-hustle income if I already pay it through my employer?
Class 1 National Insurance applies to employment and Class 4 to self-employed profits. Both can apply, although annual maximum-contribution rules may affect the final amount in some cases.
Limits of This Illustration
The result includes estimated liability and payment figures under the stated assumptions. It is not a recommendation about how much money to reserve.
HMRC record-keeping requirements can apply to trading income and the use of the trading allowance. This calculator does not determine which records are required for a particular activity.
Where registration is required, HMRC normally sets a 5 October deadline following the relevant tax year. Current deadlines and exceptions are available from HMRC.
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