Side Hustle Income Tax Calculator

Our side hustle tax calculator helps you work out exactly how much tax you'll pay on additional income from freelancing, consulting, eBay selling, Etsy shops, tutoring, or any other side business alongside your main job. Whether you're earning £500 from occasional freelance work or £10,000 from a serious side business, understanding your tax obligation is essential to avoid unexpected bills and penalties.

The UK tax system treats side hustle income as self-employment income, which means different rules apply compared to your PAYE salary. You'll pay income tax at your marginal rate, Class 2 and Class 4 National Insurance if your profits exceed certain thresholds, and you may need to register for Self Assessment. Our calculator shows you exactly what you'll owe based on your main job salary and side income combined.

One of the most useful features for side hustlers is the Trading Allowance - a £1,000 tax-free allowance for small amounts of trading or miscellaneous income. This means if your side hustle brings in less than £1,000 per year, you don't pay any tax on it and don't need to register for Self Assessment. Our calculator helps you decide whether to use the Trading Allowance or claim your actual expenses instead.

Who Should Use This Side Hustle Tax Calculator?

This calculator is designed for anyone earning additional income alongside a main PAYE job. You might be a teacher who tutors students in the evenings, an office worker who does freelance graphic design at weekends, a nurse who sells handmade crafts on Etsy, or an accountant who runs a consulting side business. The calculator works for any combination of employed and self-employed income.

It's particularly useful if you're trying to work out whether your side hustle is financially worthwhile after tax. Many people are surprised to discover that earning an extra £5,000 from a side hustle doesn't mean £5,000 in your pocket. Once you factor in income tax at your marginal rate (which could be 40% if you're a higher-rate taxpayer), Class 4 National Insurance at 9%, and the time spent on the work, the net benefit might be much less than expected.

The calculator is also essential for planning purposes. If you're earning £600 from your side hustle and considering taking on more work, you can use the calculator to see if crossing the £1,000 Trading Allowance threshold makes financial sense. Sometimes it's better to keep your side income just under £1,000 to avoid the administrative burden of Self Assessment, rather than earning £1,200 and facing tax, National Insurance, and paperwork.

Understanding How Side Hustle Tax is Calculated

Side hustle tax calculations are more complex than regular employment tax because you're combining two different types of income. Here's exactly how HMRC calculates what you owe on your side income.

Step 1: Determine Your Total Taxable Income
First, we combine your PAYE salary from your main job with your side hustle profits (income minus expenses, or income minus the £1,000 Trading Allowance if you choose to use it). Your main job salary has already had tax deducted through PAYE, but your side income hasn't been taxed yet. This combined figure determines your overall tax position.

Step 2: Calculate Income Tax at Your Marginal Rate
Here's the crucial part that catches many side hustlers out: you pay income tax on your side hustle income at your marginal tax rate, not at basic rate. If your main job salary is £45,000, you're already using up most of your basic rate band. Any side hustle income gets taxed at 40% because it pushes you into the higher-rate threshold. This is why a £5,000 side hustle might only net you £2,550 after tax and National Insurance.

For example, if you earn £35,000 from your main job and £8,000 from your side hustle, your total income is £43,000. The first £12,570 is tax-free (Personal Allowance). Your salary uses up £22,430 of the basic rate band (£35,000 - £12,570), leaving £15,270 of basic rate remaining (the basic rate band ends at £50,270). Your £8,000 side hustle income falls entirely within this remaining basic rate allowance, so you'll pay 20% income tax on it - that's £1,600.

Step 3: Add Class 4 National Insurance
If your side hustle profits exceed £12,570 per year, you pay Class 4 National Insurance at 9% on profits between £12,570 and £50,270, then 2% above that. However, this is on your self-employment profits only, not your total income. So if you earn £30,000 from your main job (which pays Class 1 NI) and £15,000 from your side hustle, you'll pay Class 4 NI on £2,430 of your side income (£15,000 - £12,570 threshold = £2,430), which is £219.

Step 4: Consider Class 2 National Insurance
If your side hustle profits are £6,725 or more per year, you also need to pay Class 2 National Insurance, which is £3.45 per week (£179.40 annually for 2026/27). This is a flat weekly charge that ensures you continue building up National Insurance credits towards your state pension. Many people forget about this small charge and are surprised by it on their Self Assessment bill.

Trading Allowance: Should You Use It?

The £1,000 Trading Allowance is one of the most underused tax breaks available to side hustlers. Introduced in April 2017, it allows you to earn up to £1,000 from self-employment or casual services without paying any tax and without needing to tell HMRC at all. However, there's a crucial decision to make: should you use the allowance or claim your actual expenses instead?

When to Use the Trading Allowance: If your side hustle expenses are less than £1,000, always use the Trading Allowance. For example, if you earn £800 from dog walking with minimal expenses (just a few dog treats and leads costing £50), using the Trading Allowance gives you £800 tax-free. If you claimed actual expenses instead, you'd have £750 taxable income (£800 - £50), resulting in unnecessary tax.

The allowance is also perfect for side hustles with low overhead costs. Tutoring, consulting, coaching, and service-based businesses often have minimal expenses beyond your time. If you earn £900 from private tutoring with £100 in travel costs and materials, the Trading Allowance means you owe nothing. Without it, you'd pay tax on £800 of profit.

When to Claim Actual Expenses Instead: If your expenses exceed £1,000, you're better off claiming them. An Etsy seller who makes £5,000 revenue but spends £2,500 on materials, packaging, Etsy fees, and postage should claim actual expenses. Their taxable profit would be £2,500, compared to £4,000 if they used the Trading Allowance (£5,000 income - £1,000 allowance).

You cannot mix and match - it's either the full £1,000 Trading Allowance or all your actual expenses. You make this choice each tax year when completing your Self Assessment. Our calculator shows you the tax owed under both scenarios so you can see which option saves you more money.

How to Use This Calculator: Step-by-Step Guide

Main Job Annual Salary: Enter your gross annual salary from your main employed position before any deductions. This is your salary as stated in your contract or shown on your P60. If you have multiple PAYE jobs, add them together. Don't include any self-employment income here - that goes in the next field.

Side Hustle Annual Income: Enter your total gross income from all self-employment and trading activities for the tax year. This is your revenue before expenses, not your profit. For example, if you sold £3,000 worth of items on eBay, enter £3,000 even if you spent £1,500 on inventory. If you do freelance work, enter all the invoices you raised, not what you received after expenses.

Use Trading Allowance: Check this box if you want to use the £1,000 Trading Allowance instead of claiming actual expenses. The calculator will show you the tax difference between using the allowance and claiming expenses, helping you make the right choice. Generally, if your side income is under £1,000 or your expenses are low, use the Trading Allowance. If you have significant business costs, leave it unchecked and claim actual expenses in your Self Assessment return.

Teacher with Evening Tutoring Business

Sarah is a primary school teacher earning £32,000 who tutors children after school for £40 per hour. She works 4 hours per week during term time (39 weeks), earning £6,240 annually. Her expenses are minimal - £200 for materials and £400 for travel. Using the Trading Allowance, she'd pay tax on £5,240 (£6,240 - £1,000). Claiming actual expenses, she'd pay tax on £5,640 (£6,240 - £600). The Trading Allowance saves her £80 in tax. Her total tax on the side income is approximately £1,048 (20% income tax) plus £0 in Class 4 NI (under £12,570 threshold), leaving her with roughly £5,192 after tax.

Nurse Running Handmade Jewelry Business on Etsy

James works as a nurse earning £35,000 and sells handmade jewelry on Etsy, generating £12,000 in sales. His costs are substantial: £4,500 for materials, £800 in Etsy fees, £600 for postage and packaging, totaling £5,900. He should definitely claim actual expenses rather than the Trading Allowance. His taxable profit is £6,100 (£12,000 - £5,900). This is taxed at 20% income tax (£1,220) plus Class 4 NI on profits exceeding £12,570 - but since his self-employment profit is only £6,100, he pays no Class 4 NI. He owes approximately £1,220 in total tax, leaving him £4,880 profit after tax.

IT Consultant with Weekend Freelance Work

Michelle earns £55,000 from her main job in IT and does freelance consulting on weekends, bringing in £15,000 annually. With £1,500 in expenses (software subscriptions, training, travel), her profit is £13,500. Because her main salary already puts her in the higher-rate tax band, this entire £13,500 is taxed at 40% (£5,400). She also pays Class 4 NI at 9% on profits above £12,570, which is £83.70 (9% of £930), plus Class 2 NI of £179.40 per year. Her total tax bill on the side income is £5,663, leaving her with £7,837 after tax - just 52% of her gross freelance income.

Part-Time Retail Worker with eBay Reselling

David works part-time in retail earning £18,000 and resells vintage items on eBay for £3,500 annually. His purchase costs and eBay fees total £2,200, giving him £1,300 profit. He should claim actual expenses since they exceed £1,000. His total income is £19,300 (£18,000 + £1,300). After the Personal Allowance of £12,570, he pays 20% tax on £6,730, which is £1,346. However, most of this tax is already paid through PAYE on his main job. The additional tax on his £1,300 side income is just £260 (20%). He pays no Class 2 or Class 4 NI because his profits are under £6,725. Total tax on side income: £260, leaving him with £1,040 after tax.

This calculator provides accurate estimates for straightforward side hustle scenarios where you have one employed position and one self-employment activity. However, it doesn't account for certain complexities like multiple side businesses, carry-back losses from previous years, capital allowances on expensive equipment, or Construction Industry Scheme deductions if you work in construction.

The calculator assumes you're using the standard Trading Allowance rules. If your side hustle has grown into a significant business with substantial turnover (approaching the £90,000 VAT threshold), complex expense structures, or if you're considering operating through a limited company instead, professional accounting advice is worthwhile. The tax you can save often exceeds the accountant's fee.

Consider consulting a qualified accountant if your side hustle profits exceed £20,000 annually, you're approaching or exceeding the VAT registration threshold, you want to claim capital allowances on equipment over £1,000, you're considering incorporating your business, or you have multiple income sources including rental property, dividends, or foreign income.

About This Calculator

This side hustle tax calculator is maintained by Mia Carragher, who writes practical guidance to help UK taxpayers understand their tax obligations, with a focus on helping employed individuals navigate self-employment tax alongside their main job. The calculations are based on HMRC's official tax rates, National Insurance thresholds, and Trading Allowance rules for the 2026/27 tax year.

We update this calculator immediately after each Budget to reflect any changes to tax rates, National Insurance thresholds, or the Trading Allowance. The methodology follows HMRC's guidance on calculating tax on mixed employment and self-employment income, ensuring your marginal tax rates are applied correctly to your side income.

This calculator is for guidance only and should not be considered financial or tax advice. Tax calculations can be complex, especially when combining employed and self-employed income. Always keep accurate records of your income and expenses, and consider professional advice if your side hustle becomes a significant income source. Remember to register for Self Assessment by 5 October if required, as late registration carries automatic penalties.