What is disposable income?
Two definitions are worth knowing. In strict economic terms, disposable income is what you keep after income tax and National Insurance. In everyday usage, the phrase usually means something looser: the money left over once the rent is paid and the bills are settled. This calculator works with the second meaning, which is closer to what economists call discretionary income: what's left after tax, NI and the essentials.
We've kept "disposable income" as the name of the tool because that's the term most people search for and use day-to-day. The number on the page is precisely defined a few lines down: your take-home pay minus rent or mortgage, council tax, energy, water, groceries and transport. Anything you spend on top of that, from savings to subscriptions to a Friday night out, comes out of this figure.
The headline number combines two things that usually get reported separately: your tax position and your local cost of living. Most "take-home pay" tools stop at the first; most "cost of living" tools ignore your income. Putting them together is the only way to answer the question that actually matters when you're comparing places to live.
How disposable income varies across the UK
On the same salary, your disposable income can swing by hundreds of pounds depending on where in the UK you live. Take a single person earning £30,000 a year. Their take-home pay is identical wherever they're based (income tax is national, with the exception of Scottish bands). What changes wildly is what's left after rent and bills.
In a place like East Renfrewshire, someone on the local median salary keeps around £1,578 a month after essentials. In central London on the same salary, the same person can land in negative territory: rent alone eats most of the take-home pay before council tax and bills even arrive. That's not a hypothetical comparison, it's the maths the calculator above is doing.
Rent is the single biggest driver of the gap. A one-bed in Hartlepool can cost a quarter of what the equivalent property costs in zones 1 to 2 of London. Council tax helps too: Scottish councils generally charge less than English ones, and the gap can run to over £800 a year at Band D. Energy, water, and groceries vary by much smaller amounts.
The result is that disposable income is a far more honest measure than gross salary when you're comparing places to live. A £35,000 job in a low-cost area can leave you better off month-to-month than a £55,000 job in a high-cost one. Try a few combinations above to see how the numbers move.
How the calculator works
The calculator runs in two steps. First it works out your monthly take-home pay using HMRC income tax bands and National Insurance rates for the 2026-27 tax year. If you select a Scottish area, Scottish income tax rates are applied automatically because Scottish taxpayers use a different set of bands.
Second, it subtracts the essential living costs for your chosen area: rent for the bedroom count you pick (from the ONS Price Index of Private Rents), council tax at the band you select, energy from the Ofgem price cap mapped to the area's region, water from the local water company, plus standard estimates for groceries, transport and childcare.
What's left is your disposable income. As you change any of the inputs, the figure updates instantly. There's no submit button. Couple households can include a partner's salary; tax is calculated individually on each because UK income tax is assessed per person.
What counts as essential living costs
We include the costs you can't easily skip: rent or mortgage, council tax, energy, water, groceries, transport, and childcare if you have children. Each one is pulled from official sources or uses the same estimates as our cost of living calculator so the two tools agree.
We explicitly do not include savings contributions, pension contributions beyond auto-enrolment, student loan repayments, debt repayments, subscriptions, dining out, clothing, holidays, or discretionary spending. The disposable income figure represents what you have available to allocate across all of those things, plus anything left over.
If you have specific commitments that don't show up here (a hefty student loan repayment, large pension contributions, dependants you support), subtract them from the disposable figure manually to get a more accurate picture of your free cash.
What is a good disposable income?
There's no universal answer, but a rough rule of thumb is useful: if you have around 20 to 30 percent of your take-home pay left after essentials, that's a comfortable position. You can save meaningfully, absorb the occasional bad month, and still spend on things you enjoy. Below 10 percent, things are tight: there's not much margin for an unexpected bill or a salary squeeze.
A negative disposable income on the calculator means your essential costs exceed your income on paper. In practice people adjust: share a flat, take a cheaper property, downsize transport, relocate. The calculator is showing you what the maths says before any of those adjustments.
For context, the ONS reports median UK household disposable income at around £35,000 a year, or roughly £2,900 a month. That's a household-level figure including pensioners and multi-earner families, so it sits well above the single-person figures we show.
Methodology
Tax rates are HMRC 2026-27. Scottish rates from the Scottish Government for the same year. National Insurance uses the 8 percent main rate and 2 percent upper rate. The personal allowance taper above £100,000 is applied.
Living costs use ONS PIPR rents at your chosen bedroom count, MHCLG / Scottish / Welsh Government council tax, the Ofgem price cap for energy, and average annual bills from Water UK / Discover Water for water. Grocery, transport and childcare follow the same standard estimates as our cost of living calculator. Full details on our about page.