UK Buy-to-Let Mortgage Calculator (2026)

Use Rightmove/Zoopla for rent comparables — pick the realistic achieved rent, not the optimistic asking rent.

LTV is auto-calculated. For product-transfer scenarios, use your current outstanding balance as the loan amount.

For couples buying jointly, model each spouse separately and sum — income allocations can be set via Form 17 if beneficial.

Individual applies Section 24; limited company uses Corporation Tax at 19%.

You're looking for all three stress scenarios to be green (positive profit). Amber on the combined scenario is acceptable if you hold 6+ months of reserves.

The recommended structure is shown based purely on tax — adjust for extraction needs, mortgage rate differences (ltd co rates are typically 0.5–1% higher) and accounting costs (£700–£2,000/year).

Lenders use a "stress rate" (not your pay rate) to calculate required rent. 2-year fixes stress at the higher of pay rate +2% or 8%. 5-year fixes can use the pay rate directly (or +1%). This is why BTL borrowers on thin yields are being pushed towards 5-year fixes post-2022 rate rises — it's often the only way to meet ICR.

Higher-rate landlord: £12,000 rent, £6,000 mortgage interest, £2,000 other costs. Pre-2020: profit = £4,000; tax = £1,600. Post-Section-24: taxable = £10,000 (rent − costs, interest NOT deducted); tax = £4,000, less 20% credit on £6,000 = £1,200. Net tax = £2,800. Effective tax went from 40% to 70% of pre-Section-24 profit. This is why many higher-rate landlords incorporated 2019–2023.

SPV (Special Purpose Vehicle) set-up: ~£50 + accounting fees. Annual accounts + CT600: £700–£2,000/year. Mortgage rate premium: typically 0.4–1% above individual BTL. ATED (Annual Tax on Enveloped Dwellings): applies if company owns residential >£500k value. Dividend extraction: 0% first £500 (2026), then 8.75%/33.75%/39.35% by band. Director's loan account strategy can defer or eliminate extraction tax if you lent the deposit to the company.

3% surcharge applies to additional residential property purchases over £40k. Limited companies pay the 3% surcharge from £0 — no first-home exemption. Combined with standard SDLT rates, a £250k BTL pays ~£12,500 on purchase. Mixed-use (genuine commercial element) and uninhabitable property may qualify for refund — see the SDLT Refund Checker.

Pair this with the Stamp Duty Refund Checker (check for overpayment on purchase), the Property CGT Calculator for exit planning, and the Credit Card Payoff Planner if managing deposit via 0% balance transfer.