Estimate your employed + self-employed tax
Use this free calculator to estimate combined UK tax when you earn from both a salary and self-employed work. Figures are annual and intended as a planning estimate.
How this employed and self employed tax calculator helps
If you have a day job and a side business, tax can feel confusing fast. You may have PAYE deductions from your employer, then another bill from self-employment profits through Self Assessment. This calculator combines both income streams in one view so you can quickly estimate:
- Income tax based on your total taxable income
- Employee National Insurance on salary
- Class 4 National Insurance on self-employed profits
- Optional student loan deductions based on total income
- Estimated remaining balance to pay (or possible overpayment)
What counts as employed income vs self-employed income?
Employment income
This is your gross salary from an employer before tax deductions. In most cases, your employer handles tax and employee National Insurance through PAYE each month.
Self-employed income
For the self-employed field, enter your profit, not your turnover. Profit means your business income after allowable business expenses. If you enter turnover instead of profit, your estimate will likely be too high.
How the tax estimate is calculated
This page uses a simplified UK-style model (England/Wales/Northern Ireland bands) for annual planning. The steps are:
- Add employment income and self-employed profit.
- Apply pension contributions to reduce taxable income.
- Apply personal allowance (with taper above high-income thresholds).
- Calculate income tax across basic, higher, and additional-rate bands.
- Calculate National Insurance separately for employment and self-employment.
- Calculate student loan repayments if a plan is selected.
- Subtract any tax already paid to estimate your balance.
Because real tax returns include more details (benefits, marriage allowance, capital gains, dividends, and more), treat this as a planning tool rather than a final filing figure.
Practical planning ideas for mixed-income earners
1) Save for tax as you earn
A common rule is to set aside a fixed percentage of side-income profit (for example 25% to 35%) into a separate tax savings account. This reduces stress when payment deadlines arrive.
2) Keep business records clean
Track invoices, receipts, software subscriptions, mileage, and home-office costs consistently. Clean records can reduce errors and help ensure you claim valid expenses.
3) Use pension contributions strategically
Pension contributions may reduce your taxable income while building long-term wealth. For many people, this is one of the most efficient legal ways to lower current-year tax pressure.
4) Review your tax code
If your side income has changed significantly, your tax code or payments on account might need adjustment. Staying proactive can prevent surprise bills.
Example scenario
Imagine you earn £45,000 from employment and £12,000 in self-employed profit. You contribute £2,000 to a pension. In this case, your combined tax exposure is often higher than PAYE alone, and the calculator helps you estimate the extra amount before filing season.
Try changing each input to model best-case and worst-case outcomes. Scenario testing is one of the easiest ways to improve cash-flow planning throughout the year.
Frequently asked questions
Do I always need Self Assessment if I am employed?
Not always, but many employed people with meaningful self-employed income do. HMRC rules can change, and thresholds matter, so check current guidance each tax year.
Why is my tax rate higher than expected?
When income from salary and self-employment is combined, more of your total may fall into higher tax bands. You may also face separate National Insurance charges and student loan deductions.
Can this replace advice from an accountant?
No. This tool is for education and planning. For filing accuracy, relief claims, and complex situations, get advice from a qualified accountant or tax adviser.
Final note
Having both employed and self-employed income can be a powerful way to build financial resilience. The key is not just earning more, but forecasting tax early, keeping records disciplined, and making decisions before deadlines force your hand.