As of 13 August 2026, AI can calculate how much you can borrow for a house.
Most people should hand this to a purpose-built tool.
Can you do it?
5 minutesto a draft.
30 minutesto something you’d act on.
Cost, all in£0
Skill neededchat-fluent
Who has to check ityou
What the alternative costsNo comparable alternative price is supplied in the available tool data.
If this goes wrong: you search for properties above a lender's real affordability limit or commit to repayments you cannot comfortably sustain.
What to actually do
Use a tool built for this
The route this page recommends
Do it yourself
Second choiceA chat interface, chat-fluent skill, and roughly 30 minutes until you can act on the result.
How to actually do it
- Open a notes document and record your gross annual income, employment status, regular and variable pay, existing borrowing, credit-card balances, dependants, deposit and expected property costs.
- Remove account numbers, passwords and other unnecessary identifying information, then paste the remaining figures into the prompt.
- Paste the completed prompt into ChatGPT, Claude or Gemini and answer any follow-up questions using figures from payslips, statements and your own budget.
- Save the estimate, including its assumptions, cautious range, repayment discussion and list of missing information.
- Compare each input and assumption against your payslips, bank statements and current monthly budget, then correct the prompt and rerun it where anything is incomplete or wrong.
- Check the result against current UK lender affordability calculators and request an agreement in principle before treating the estimate as a house-search budget.
- For a serious purchase or unusual income, send the figures and the agreement in principle to a qualified mortgage adviser before making an offer.
Prompt
Estimate how much I may be able to borrow for a UK residential mortgage. Treat this as an affordability estimate, not a mortgage offer or financial recommendation. Use only the information I provide, show the arithmetic and state every assumption. Ask for any missing information before calculating. Consider gross basic income, employment status, variable income, existing loans and credit commitments, credit-card balances, dependants, deposit, expected property price, term, and any regular costs that affect affordability. Separate the estimated borrowing amount from the total possible purchase budget after adding the deposit. Show a cautious range rather than one precise figure, explain which facts could reduce the result, and list the figures I must confirm with a lender. Do not invent lender criteria, interest rates, tax rules or figures. Do not ask me to paste account numbers, passwords or other unnecessary private data. End by telling me to compare this estimate with current UK lender affordability calculators and an agreement in principle, and state that this is not professional advice. My information is: [paste your figures and circumstances here].
Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.
Hand it to a person
The distant thirdA person who owns the outcome does this end to end, worth it when the failure is dear.
What it gets wrong
- AI cannot know which lender's current affordability rules will apply to you unless you check the lender directly.
- AI cannot turn a rough estimate into a mortgage offer or agreement in principle.
- AI cannot judge whether a proposed repayment remains comfortable after changes to your income, costs or household circumstances.
- AI cannot verify your income, debts, credit history or the accuracy of figures you provide.
- You carry the consequences of searching for or committing to a property based on an incorrect estimate.
Even on a YES, the friction has a name: judgement under ambiguity, stakes of error and real time truth.
How we scored this
Five axes, each scored nought to two by hand: ten means AI carries the task cleanly, and the thresholds that turn a total into YES, PARTLY or NO are published in the methodology. Each axis name links to its definition.
| Axis | Score (0–2) |
|---|---|
| Output | 2 |
| Inputs | 2 |
| Verification | 1 |
| Liability | 1 |
| Effort delta | 2 |
| Total | 8 / 10 |
The methodology and its thresholds are published in full.
FAQ
- Can ChatGPT tell me how much I can borrow for a mortgage?
- Yes, it can produce a rough UK mortgage affordability estimate from your income, deposit, debts and household details. It cannot guarantee what a lender will offer, so check the assumptions against your records and obtain an agreement in principle.
- How accurate are AI mortgage affordability calculators?
- They can be accurate arithmetic based on the figures you enter, but the result may not match a lender's decision. Lenders use their own current rules and may assess variable income, credit commitments and household costs differently.
- What information do I need to calculate how much I can borrow?
- Gather your gross income, employment status, variable pay, existing borrowing, credit-card balances, dependants, deposit and regular household costs. Do not share passwords or account numbers with a chatbot.
- Should I use AI to decide what mortgage I can afford?
- Use it to organise figures and explore cautious scenarios, not as the final decision-maker. This is not professional advice, and a serious case needs a qualified mortgage adviser as well as a lender's affordability assessment.
Nearby answers
Assessed by gpt-5.6-luna (gpt-5.6-luna) on 2026-08-13, second-checked by an independent model. Wrong somewhere? Email [email protected] and it gets re-checked.
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