The short version: gross income is everything you earn before anything gets taken off, and net income is what's left after tax, National Insurance, fees and expenses. Most people price their work, budget their life and plan their side hustle around the wrong one, and that's how you end up skint in January with a tax bill you didn't see coming.
What gross income means
Gross income is the full amount before any deductions. If you invoice a client £5,000 for a project, your gross income is £5,000. If your salary slip says £42,000 a year, that's gross. Nothing has been taken off yet. This is the number that looks good on a LinkedIn post. It is not the number in your bank account.
For a business, gross income (sometimes called gross revenue or turnover) is total sales before you subtract the cost of running things: software, subcontractors, materials, travel, your accountant's fee, all of it.
What net income means
Net income is what's left after every deduction has been taken. For an employee, that's after income tax, National Insurance and pension contributions come out of your payslip. For a self-employed person, net income is your profit: total income minus allowable business expenses, and then minus the tax and National Insurance you owe on that profit.
Net is the real number. It's what you have to live on, save, or reinvest. If you're building a simple income statement in a spreadsheet, gross sits at the top and net sits at the bottom, with every expense line pulling the number down between the two.
A worked example
Say you run a small social media consultancy as a sole trader in the UK. Over a tax year you invoice clients a total of £60,000. That's your gross income.
- Business expenses (software subscriptions, a co-working desk, travel to client meetings, a laptop): £8,000
- Taxable profit: £52,000
- Income tax on that profit (roughly, using 2026 UK bands with the £12,570 personal allowance): around £8,500
- Class 4 National Insurance on profits above the threshold: around £2,200
- Net income left to spend or save: roughly £41,300
That's a gap of nearly £19,000 between the number you'd put on a mortgage application boast and the number that's yours. If you'd quietly planned your spending around £60,000, you'd have a very uncomfortable spring.
Why this trips people up (even smart ones)
The uncomfortable truth nobody likes saying out loud: most people who go self-employed or start a side hustle budget off gross income without meaning to. They see £1,000 land for a freelance project and mentally spend it like it's £1,000, when a third of it or more is already owed to HMRC. It's not stupidity, it's that gross is the number you're told, shown and chase, while net is the number nobody mentions until the tax bill lands.
This matters even more if you're running a side hustle alongside a job. You need to declare side hustle income to the tax office once you're over the £1,000 trading allowance, and the tax on that extra income often gets charged at your highest marginal rate, because it stacks on top of your salary. A side income of £6,000 taxed at 40% leaves you with £3,600, not £6,000. Plenty of people don't realise this until the bill arrives.
Gross vs net on a payslip
If you're employed, your payslip spells it out but people still skim past it:
- Gross pay: your full salary before deductions
- Minus income tax (PAYE)
- Minus National Insurance
- Minus pension contribution (often 5% or more)
- Minus student loan repayment if applicable
- Net pay: what hits your bank account
A £35,000 salary typically lands as roughly £2,300 to £2,400 a month net, not the £2,916 you'd get dividing £35,000 by 12. That gap catches out a lot of people negotiating a new job offer who compare gross figures between two roles without checking what pension schemes or benefits differ.
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Gross vs net for a business
For a limited company it's a bit more layered. You've got:
- Gross revenue (total sales)
- Gross profit (revenue minus the direct cost of delivering your product or service)
- Operating profit (gross profit minus overheads like rent, salaries, software)
- Net profit (after tax, interest and everything else)
Each stage tells you something different. Gross profit tells you if your pricing covers what it costs to deliver the work. Net profit tells you if the whole business makes money once you've paid yourself, your team and the taxman. A business can have a brilliant gross margin and still lose money overall because overheads are bloated, which is exactly why relying on gross figures to judge how well something is doing is a mistake that catches out even people who should know better.
Why this matters for pricing your work
If you freelance or run a service business, price from net backwards, not gross forwards. Decide what net income you need to live on, add back your estimated tax and National Insurance, add back your business expenses, and only then do you have a gross revenue target that supports the life you want. Most people do it the other way round: pick a nice round gross number that sounds impressive and hope the rest sorts itself out.
This is also where people chasing passive income ideas trip up. A course or digital product bringing in £2,000 a month gross sounds brilliant until you take off platform fees, payment processing, refunds and tax, and you're left with far less. Nothing is as passive, or as net, as it looks on the sales page, and if you want the blunter version of that, I've written about why a side hustle isn't really passive income at all.
A simple way to stay on top of it
You don't need complicated software for this. Open a spreadsheet, put every invoice or payment in as gross income, then add columns for expenses, tax set aside and National Insurance set aside. Whatever's left in the final column is your real net number, the one you're allowed to spend. I'd set aside 25 to 30% of any self-employed income the moment it lands, straight into a separate savings account, so tax time never becomes a crisis. If you want a real breakdown of how to structure that tracking, it's worth reading through how to build an income statement using a spreadsheet, because the habit of separating gross from net at the point of earning, not at the point of filing, is what keeps people out of trouble.
Frequently asked questions
Is gross income the same as salary?
Gross income is the broader term, salary is one type of it. Your gross salary is the figure on your contract before tax, National Insurance and pension are deducted, and it's also used as shorthand for your overall gross income if a job is your only earnings.
Do I pay tax on gross or net income?
Tax is calculated on your gross income minus any allowable deductions or expenses, not on your net income, because net income is what's left after tax has already been taken off. For the self-employed, that means tax is worked out on profit, which sits between gross and net.
Why is my net income so much lower than gross?
Because income tax, National Insurance, pension contributions and, for the self-employed, business expenses all get taken off gross income before you see the net figure, and in the UK that gap is often 20 to 35% depending on your income band and whether you're employed or self-employed.
Should I budget using gross or net income?
Always budget using net income, since that's the actual money available to spend or save. Using gross income to plan a budget is one of the most common reasons people, especially new freelancers and side hustlers, end up short when a tax bill or pension deduction arrives.
