About

Where our numbers come from

Every figure on First Key is worked out in one place, from rates kept in one place, so the guides and calculators always agree. Here's where those rates come from and when we last checked them.

• Stamp Duty, LBTT and LTT

  The bands and rates for first-time buyers and people moving home in each nation. Northern Ireland uses the same Stamp Duty as England.

  • GOV.UK: Stamp Duty Land Tax residential rates
  • Revenue Scotland: LBTT residential rates
  • Welsh Government: Land Transaction Tax rates and bands

  Last checked 2026-10-01

• Lifetime ISA

  The yearly limit, the £1,000 bonus, the age rules, the £450,000 price limit and the withdrawal charge, and the planned replacement from April 2028.

  • GOV.UK: Lifetime ISA

  Last checked 2026-10-04

• Take-home pay

  Income tax bands (with Scotland's own), the personal allowance and employee National Insurance, for a rough monthly take-home figure. It leaves out pensions, student loans and tax code quirks, so it's an estimate.

  • GOV.UK: Income Tax rates and allowances
  • GOV.UK: Scottish Income Tax
  • GOV.UK: National Insurance rates

  Last checked 2026-10-01

• How much you could borrow

  We use 4.5 times income as what many lenders lend, and up to 5 times as a stretch, with a deposit of at least 5%. The Bank of England limits how much lending can go above 4.5 times income, which is why it's a common ceiling. Each lender decides for itself.

  • Bank of England: financial stability

  Last checked 2026-10-01

• Mortgage payments

  A standard repayment mortgage formula. Unless you change it, we assume 4.5% over 30 years, a round figure near typical new mortgage rates. Your deal's rate will differ.

  • Bank of England: effective interest rates

  Last checked 2026-10-01

• Price check and local sold prices

  The average sold price for the home's council area and property type, the first-time buyer average and the change on a year before, from the Land Registry's UK House Price Index. It runs a month or two behind and covers every size of home, so it's a starting point, not a valuation. Council areas come from postcodes.io.

  • GOV.UK: UK House Price Index
  • HM Land Registry: UK House Price Index data

  Last checked 2026-10-04

• Shared ownership

  England's scheme for homes from April 2021: the 10% smallest share, rent of up to 2.75% a year on the part you don't own, the income limits and buying more in 1% steps.

  • GOV.UK: Shared ownership homes

  Last checked 2026-10-04

• Council tax and energy

  A typical bill for the home's council tax band in each nation (domestic rates in Northern Ireland), and a typical energy bill for its EPC rating. Real bills depend on the council and how you live.

  • GOV.UK: Council Tax
  • Ofgem: Energy price cap

  Last checked 2026-10-01

• Legal fees, searches, survey and moving

  Our own typical figures for a first-time buyer's solicitor, searches, a survey and a small move. Quotes vary, so get your own.

  Our own estimate.

  Last checked 2026-10-01