Is My Side Hustle Worth It?

The money hierarchy. Gross revenue is what the platform or client pays before anything comes off it. Cash generated subtracts immediate cash costs (fuel, platform fees, materials). True profit further subtracts allocated fixed costs and non-cash economic costs like vehicle depreciation and wear — costs that are real even though no cash leaves your account that day. The after-tax figure estimates what's left once income tax and Class 4 National Insurance on the profit are accounted for.

Vehicle costs and "would you own this anyway?" If you say you'd own the vehicle regardless of this side hustle, fuel, the delivery insurance uplift and per-mile wear are counted in full (they're directly caused by the extra driving), but servicing, tyres, MOT and road tax are only attributed in proportion to how much of your total annual mileage this side hustle actually adds — using the personal-mileage figure you provide. If you bought the vehicle specifically for this, or it was partly influenced by it, all vehicle costs are attributed in full and any purchase cost is treated as a startup cost.

Tax deductibility vs economic cost. "True profit" includes every economic cost you've entered, whether or not it's tax-deductible — that's the honest picture of what the activity costs you. The tax estimate only uses costs you've marked as likely tax-deductible. These are frequently different things: depreciation, for example, is a real economic cost but HMRC uses its own capital allowances rules rather than straight-line depreciation, so it often isn't deductible in the way modelled here. Check the deductibility box on each cost only if you're reasonably confident, and treat the tax figure as an estimate, not a return.

UK tax estimate. Income tax is calculated on your total income (existing income plus side-hustle taxable profit) using 2026/27 tax year thresholds for your chosen jurisdiction, including the personal allowance taper above £100,000, then compared against tax on your existing income alone — the difference is the incremental tax this activity adds. Class 4 National Insurance is calculated on the side-hustle profit alone, using its own lower and upper profits thresholds, independent of your employment income (Class 1 NI on your job is separate and not modelled here). Employer NI, student loan repayments, the High Income Child Benefit Charge and pension tax relief aren't modelled. Rates and thresholds are centralised in the tool's configuration so they can be updated for a new tax year.

Break-even. The "Lifetime" view counts every startup cost you've entered (adjusted for the ownership question) toward payback. The "From today" view is meant for when you've already spent that money — it treats sunk costs as sunk and doesn't use spending that's already happened to justify continuing, in line with the "decision from today" thinking this tool tries to encourage.

Target rate. Given a target after-tax hourly rate, the tool searches for the gross revenue that would produce it once your current costs and tax position are applied — it does not simply scale your current rate, since tax and fixed costs don't move in a straight line with revenue.

Scenarios. Poor and good scenarios apply your own percentage adjustments to revenue and cash costs, then re-run the whole calculation — not a single flat multiplier on the final answer.

What this deliberately doesn't do. It doesn't output a "worth it / not worth it" verdict, doesn't put a made-up number on enjoyment or flexibility, and doesn't claim self-employed earnings below minimum wage are illegal (minimum wage law depends on employment status, which this tool doesn't determine). It also doesn't yet model scaling to full-time, recurring/residual income, seasonality profiles, or track actual results over time — see the version history for what's planned.