FinToolSuite

Loan Affordability Calculator

Updated April 17, 2026 · Debt · Educational use only ·

Maximum loan you can afford on your income.

Calculate maximum loan you can afford based on income, existing debts, and lender ratios. Enter existing debt payments and max dti to see max loan amount.

What this tool does

Enter monthly income, existing debt payments, max DTI percentage, term, and rate. The tool shows max loan amount.


Enter Values

Formula Used
Monthly available payment
Monthly rate
Months

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Calculations, display, or translation — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Loan affordability based on debt-to-income ratio. 4,000 income, 400 existing debts, 36% DTI limit = 1,040/month available for new loan. At 8% over 5 years = 51,300 max loan.

Run it with sensible defaults

Using monthly income of 4,000, existing debt payments of 400, max dti of 36%, loan term of 5, the calculation works out to 51,291.17. 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 — Monthly Income, Existing Debt Payments, Max DTI %, Loan Term, and Annual Rate — 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

Monthly available = (income × max DTI) - existing debts. Reverse amortisation gives max loan. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Why payoff plans work

Debt feels overwhelming when it's an abstract total. Break it into a payoff date and a monthly figure and the problem becomes finite — you can see the finish line. That visibility is what this tool provides, and for many people it's the difference between dithering and acting.

What this doesn't capture

Real payoff journeys include missed payments, fee changes, balance transfers, and promotional rates that reset. The calculation assumes a steady plan; reality is rarely that clean. Use the figure as the best-case plan against which actual progress gets measured.

Related calculations worth running

Plans get firmer when you triangulate. Alongside this one, the gold loan calculator, the personal loan vs credit card calculator, and the amortisation schedule calculator tend to come up in the same conversations. Running two or three together exposes inconsistencies in any single assumption — which is usually where the useful insight lives.

Example Scenario

Loan affordability produces max loan based on the inputs provided.

Inputs

Monthly Income:4,000 £
Existing Debt Payments:400 £
Max DTI %:36
Loan Term:5 years
Annual Rate:8
Expected Result£51,291.17

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Monthly available = (income × max DTI) - existing debts. Reverse amortisation gives max loan.

Frequently Asked Questions

What DTI do lenders use?
Varies. Conservative 28-36%. Some allow up to 43-50%. Calculator default 36% standard.
Why might lender offer less?
Credit score, employment history, savings, other risk factors. Calculator shows mathematical max — actual approval may be lower.
Affordable vs maximum?
Maximum stretches budget tight. Affordable usually 60-75% of maximum for comfort margin.
What about secured loans?
Secured loans (mortgages) have separate affordability tests considering property value, deposit, etc. This calculator for unsecured.

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