Start with net income
Use the amount that actually reaches the household after payroll deductions. This makes the result easier to compare with real bills and spending.
See exactly what this purchase does to your budget.
Enter your take-home income and real monthly costs. WorthChex shows the pound amounts and the percentage of income for existing spending, the new payment, total commitments and what remains.
Private, browser-based calculation
Your figures stay in the browser. No bank connection or account is required.
What the result will show
Every key ratio is calculated from your take-home income. You will see housing %, debt %, existing spending %, payment %, total commitments %, remaining income %, and savings-use percentages where the information is available.
HOW THE PERCENTAGES WORK
Transparent ratios instead of a made-up “affordability score”.
WorthChex does not turn your answers into a single score. The result shows the underlying maths so you can audit it: existing spending ÷ take-home income, new payment ÷ take-home income, and total monthly commitments ÷ take-home income. For a cash purchase, it also shows how much of the savings entered would be used and how much of the emergency target would remain covered.
Lenders use their own detailed affordability assessments based on income, expenditure and other circumstances. FCA material states that affordability assessments consider income and expenditure rather than relying on one universal income or expenditure threshold. Read FCA guidance on mortgage affordability →
HOW TO READ THE RESULT
Affordability is about the money left after the decision.
A useful affordability check starts with money that is genuinely available, not a headline income multiple. The calculator separates existing monthly commitments from the new payment so you can see how much of take-home income is already spoken for.
Convert irregular costs
Annual insurance, repairs, memberships, school costs and other non-monthly bills still affect affordability. Turning them into a monthly allowance avoids overstating spare cash.
Test a stress case
Run the calculation again with a higher payment or lower income. A plan that only works under the most favourable assumption may have little room for change.
Worked example
Suppose take-home income is £3,000 a month, existing commitments are £1,800 and the proposed new payment is £350. Existing spending is 60% of take-home income, the new payment is about 11.7%, and total commitments are about 71.7%, leaving roughly £850 before any costs you have not entered.
This is a budgeting model, not a lender affordability assessment. MoneyHelper explains that lenders can consider income, regular bills, spending and existing debts when assessing a mortgage. See MoneyHelper's mortgage affordability guidance →
REVIEWED SEPTEMBER 2026
What this calculator can and cannot tell you.
WorthChex shows the arithmetic behind a scenario. It does not know future income changes, lender underwriting rules, credit history, household risk tolerance or costs you have forgotten to enter. Use the result as a planning checkpoint, then compare it with the actual terms of the product or purchase you are considering.
For a deeper budgeting check, write down one month of bank and card spending, then add annual and irregular costs. Compare that real-world total with the figure you entered here. The more complete the inputs, the more meaningful the remaining-income figure becomes.