SIDE HUSTLE · 2026/27
Side hustle tax calculator
Work out how much of your extra income may be taxable before you budget or register for Self Assessment.
What this calculator does
Use this calculator to compare the £1,000 trading allowance with actual business expenses, then see an estimate of taxable profit before Income Tax.
Estimated result
- Taxable profit
- £3,800
- Best deduction
- Actual expenses
- After estimated tax
- £3,040
National Insurance, losses, VAT and registration requirements are outside this simplified estimate.
Worked example
If you earned £5,000 and had £1,200 of allowable expenses, the calculator compares the remaining profit with the trading allowance and shows the likely taxable amount.
Common mistakes
Do not assume the £1,000 trading allowance always beats expenses.
Do not forget other income can push the final tax band higher.
Do not treat this as a registration or VAT decision.
Why the result can differ
Different expenses, payroll jobs and tax bands can change the result.
The trading allowance can be better than expenses for some users, but not all.
National Insurance and registration rules are separate from this simple tax estimate.
What this calculator does
It compares the £1,000 trading allowance with a simple expenses-based profit estimate so you can see which approach is likely to matter most. That is useful when a side hustle starts to feel less like spare cash and more like a real taxable stream.
Worked example
If you earn £5,000 from side work and spend £1,200 on allowable costs, the result depends on whether the trading allowance or the expense-based route gives the lower taxable profit. The calculator shows the likely taxable amount before you worry about deadlines or Self Assessment registration.
Why the result can differ
Other jobs, pension deductions, tax bands and whether the income is really trading, property or something else can change the answer. This is an estimate of taxable profit, not a replacement for a full Self Assessment review.
SOURCES & REVIEW
Checked against official guidance
Last reviewed 14 July 2026 · Rule version GB-2026.27.1
Daily/weekly source monitoring. If a source changes, the affected rule set is reviewed before publication.
All source links are kept visible so you can verify the figures used on this page.
GOV.UK: Tax-free allowances on property and trading income ↗Sources, methodology and update policy →Report an issue or correction →WHY RESULTS DIFFER
Why two users can see different results
Why the result can differ
Different tax codes, payroll periods, Scottish bands, pension methods or lender assumptions can change the outcome.
One-off bonuses, pay frequency, overpayments, allowances and reliefs can move the result away from a simple annual estimate.
Where a rule depends on eligibility or legal status, this page shows an estimate and links to official guidance.
This section is intentionally repeated on key tools so the explanation stays near the result instead of being hidden in a separate policy page.
COMMON QUESTIONS
Frequently asked questions
Does the trading allowance replace expenses?
Not always. You can usually choose whichever gives the better result, but the right choice depends on your facts.
Does this include National Insurance?
No. This is a simplified Income Tax estimate only.