The biggest mistake first-time buyers make is falling in love with a house before they know what they can actually afford. By the time the numbers don't work, they're emotionally committed to a property they can't have.
Do the maths first. Everything else follows.
Your deposit — the minimum and the ideal
The minimum deposit for most mortgages is 5%. On a £250,000 property that's £12,500. On a £350,000 property it's £17,500.
But 5% gets you the most expensive rates. A 10% deposit (£25,000 on a £250k property) unlocks meaningfully better deals — typically 0.3–0.5% lower rates, saving thousands over the term. If you can wait the extra time to save a 10% deposit, the maths usually support it.
The LISA — the most underused first-time buyer tool
A Lifetime ISA gives you a 25% government bonus on up to £4,000 per year — a free £1,000 annually. That's not a small print deal. That's real money added to your deposit savings.
Rules: you must be 18–39 to open one. The money must go towards a first home worth under £450,000. You can't touch the money until you buy or turn 60 (there's a withdrawal penalty otherwise).
If you're planning to buy in 2–5 years and haven't opened a LISA, open one now. Even parking £1 in it opens your account and starts the clock.
What you can borrow
Lenders typically offer 4–4.5x your annual salary. Joint buyers use combined income. A couple earning £35,000 each (£70,000 combined) can borrow approximately £280,000–£315,000.
Existing debt, childcare costs, and car finance all reduce this figure. Get an Agreement in Principle from a lender or broker before you start viewing — it's free, quick, and tells you your real number.
Stamp duty as a first-time buyer
First-time buyers pay 0% up to £300,000 and 5% on the portion from £300,001 to £500,000. Above £500,000 there's no relief.
On a £350,000 first purchase: 0% on £300k + 5% on £50k = £2,500. A non-first-time buyer pays £7,500 on the same property. Budget for this before you add it to your deposit savings.
The realistic timeline
- Today: Open a LISA if you haven't. Start saving.
- When deposit ready: Get an Agreement in Principle.
- Offer accepted: Instruct a solicitor and book a survey.
- Completion: 8–12 weeks after offer acceptance typically.
Use the mortgage calculator to model your monthly costs at different property prices before you go to any viewings. Know your comfortable payment range. Stick to it.