Why the first-time buyer affordability calculator matters
First purchases are usually constrained by the deposit rather than income, so the fastest route to a bigger budget is often another six months of saving. This page turns that decision into a handful of inputs you can defend in a budget review: volume, unit cost, rate of adoption, and time. The output is a planning baseline, not a promise — it tells you whether the idea deserves a vendor quote, a pilot, or a pass.
- • Biggest swing factor: the down payment available
- • Second-order factor: the debts already on your file, especially car loans
- • Often ignored: the rate you can secure at your credit profile
What actually changes the answer
the down payment available moves this number first, then the debts already on your file, especially car loans. Run a conservative case and an upside case before you commit. If the maths only works in the upside case, treat it as a time-boxed test with a kill date rather than a line in next year's plan.
What to do with the result
Model the same purchase with $10k more down. If it moves the price meaningfully, delay and save rather than stretch.
FAQ
What does the first-time buyer affordability calculator work out?
It applies Max payment = min(36% × monthly income − debts, 28% × monthly income); Loan = payment × [(1 − (1 + i)^−n) ÷ i]; Price = loan + down payment to the values you enter for gross annual income, existing monthly debt payments, down payment / cash available, interest rate, loan term (years). First purchases are usually constrained by the deposit rather than income, so the fastest route to a bigger budget is often another six months of saving.
How accurate is this first-time buyer affordability calculator?
Payment capacity only. First-time buyer grants, mortgage insurance and closing costs each change the real affordability. Replace the defaults with your own invoice, usage export, payroll data, statement, or vendor quote before making a commitment — the maths is exact, so the answer is only as good as the inputs you feed it.
Which input should I stress-test first?
the down payment available. Re-run with a pessimistic value for it; if the decision flips, that assumption is the thing you need real data on before signing anything. After that, check the debts already on your file, especially car loans and the rate you can secure at your credit profile.
Which scenario should I start from?
Start with the preset closest to your situation — cautious budget, today's numbers, stronger position — then edit the sliders. Presets are realistic starting points, not benchmarks to match, and every change updates the result instantly.
What should I do after running the numbers?
Model the same purchase with $10k more down. If it moves the price meaningfully, delay and save rather than stretch. A useful planning benchmark to compare against: Median first-time buyer down payments run near 8–9% of price.
Can I share or save this calculation?
Yes. Your inputs are written into the page URL, so copying the link shares the exact scenario you are looking at — the person who opens it sees the same numbers. You can also export the inputs and results to CSV or PDF from the result card and keep it with the rest of your workings.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.