UK PAYE + Side Hustle Tax Calculator 2026/27
Got a day job and a side hustle? Work out exactly how much extra tax and National Insurance you owe through Self Assessment on your self-employed income. Includes PAYE stacking, Personal Allowance sharing, and Class 2 / Class 4 NICs.
Your Income Details
1. Employment (PAYE)
2. Side Hustle (Self-Employed)
3. National Insurance
4. Student Loan (optional)
Your Tax Breakdown
How Side-Hustle Tax Works When You Have a Day Job
If you are employed and also earn money from self-employment, freelancing, or a side gig, HMRC treats your total income as one pot for tax purposes. Your employer already deducts PAYE tax and Class 1 NICs from your salary through your tax code. However, your side-hustle profit is not taxed at source — you must declare it via Self Assessment and pay the extra tax yourself.
The key concept is income stacking. HMRC applies your Personal Allowance (£12,570 for 2026/27) to your employment income first. If your salary is less than the allowance, the unused portion is applied to your side profit. Once the allowance is exhausted, your side profit is taxed at 20%, 40%, or 45% depending on which band your total income falls into. This means a side hustle can push you into a higher tax bracket even if your day-job salary stayed the same.
The £1,000 Trading Allowance
If your side-hustle turnover is £1,000 or less in a tax year, you do not need to register for Self Assessment and you pay no tax on that income. This is called the Trading Allowance. If you earn more than £1,000, you can choose to deduct either the £1,000 allowance or your actual business expenses — whichever is higher. For most side hustles with meaningful costs (equipment, software, travel), actual expenses usually give a bigger deduction.
2026/27 Tax & NIC Rates for Side Hustlers
| Component | Threshold / Band | Rate | Paid Via |
|---|---|---|---|
| Personal Allowance | Up to £12,570 | 0% | PAYE first, then side income |
| Basic Rate | £12,571 – £50,270 | 20% | PAYE + Self Assessment |
| Higher Rate | £50,271 – £125,140 | 40% | PAYE + Self Assessment |
| Additional Rate | Over £125,140 | 45% | Self Assessment |
| Class 2 NIC | Profit above £6,725 | £3.45/week | Self Assessment |
| Class 4 NIC | £12,570 – £50,270 profit | 6% | Self Assessment |
| Class 4 NIC | Profit above £50,270 | 2% | Self Assessment |
Important: Class 2 and Class 4 NICs are calculated on your self-employed profit only, not your total income. So even if your day job pays £40,000, you only pay Class 4 on the side-hustle profit above £12,570.
Frequently Asked Questions
Do I need to tell my employer about my side hustle?
There is no legal requirement to tell your employer, but you should check your employment contract for restrictions on outside work or competing businesses. You must tell HMRC, however, by registering for Self Assessment if your side income exceeds £1,000.
Will my side hustle push me into the 40% tax bracket?
Yes, if your combined PAYE salary + side-hustle profit exceeds £50,270. The portion of your side profit that falls above this threshold is taxed at 40% (or 45% above £125,140). This is why high earners often form a limited company for their side gig — to benefit from the 25% Corporation Tax rate.
What if I make a loss in my side hustle?
You can carry the loss forward to offset against future side-hustle profits, or in some cases set it against your PAYE income for the same year (called "sideways loss relief"), which can generate a PAYE tax refund. Use the Self Assessment form to claim this.
Do I need to register for VAT?
Only if your side-hustle turnover (not profit) exceeds £85,000 in any 12-month period. If you are close to the threshold, keep monthly records. Voluntary VAT registration can be useful if you have significant VAT-able expenses to reclaim.
How do Payments on Account work?
If your Self Assessment bill is more than £1,000, HMRC assumes you will owe a similar amount next year and asks for advance payments. You pay 50% by 31 January and 50% by 31 July. These are deducted from your final bill when you file the next return.