Hobby vs business classification.

Tax authorities distinguish between businesses (can deduct full losses) and hobbies (can only deduct expenses up to revenue, not below). Standard test: profitable in 3 of last 5 years = likely business. Plus business intent factors: separate business records, time invested, expertise, profit-seeking activity. This tool gives directional guidance on classification.

8,000 revenue, 12,000 expenses, profitable 2 of 5 years, has business intent. Net result: -4,000. As business: deduct full 12,000 expenses. Taxable income: -4,000 (loss reduces other income). As hobby: deduct only 8,000 expenses. Taxable income: 0. Difference 4,000 of loss benefit.

If your activity is ambiguous, document business intent: separate bank account, business cards, marketing efforts, time logs, profit-seeking activities (raising prices, expanding services). The more business-like, the more likely tax treatment as business. Get accountant advice for borderline cases - misclassification triggers audits.

Run it with sensible defaults

Using gross revenue of 8,000, total expenses of 12,000, profit years in last 5 of 2, business intent of 1, the calculation works out to Business. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Gross Revenue, Total Expenses, Profit Years in Last 5, and Business Intent (1=yes, 0=no) — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

Business if profit 3+ of 5 years OR profit 2+ years with business intent. Business: full deduction. Hobby: deduction capped at revenue. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this in pay negotiations

Knowing the exact figure behind a headline rate gives you specific numbers to anchor to in conversations about pay. "The difference is £X per month after tax" lands harder than "a couple of grand a year". Concrete numbers move decisions.

What this doesn't capture

Tax bands, pension contributions, student-loan deductions, and benefits-in-kind sit outside this calculation. The figure is the headline; your actual position depends on local tax rules and personal circumstances. Pair with a dedicated take-home calculator for the full picture.