Offset Mortgage Calculator (UK 2024)
Calculate offset mortgage interest savings and reduced term by linking savings accounts to reduce mortgage interest charged.
Offset Mortgage Guide
How Offset Mortgages Work
Offset mortgage: links your savings account(s) with your mortgage. Mortgage interest is calculated only on (mortgage balance − offset savings balance). You can still access your savings — they remain liquid. Example: £200k mortgage, £30k savings linked. Interest charged on £170k, not £200k. Your savings effectively earn the mortgage interest rate — but without tax. £200k at 5.5%: interest £11,000/year. £170k at 5.5%: £9,350/year. Saving: £1,650/year just by linking savings.
Tax Advantages
Crucial benefit: offset 'earnings' are not taxed. Standard savings: 5% interest. Basic rate taxpayer: £100 interest × 0.80 = £80 net. Higher rate: × 0.60 = £60 net. Personal Savings Allowance: basic rate £1,000/year tax-free. Higher rate £500. Additional rate £0. Above PSA: pay tax at marginal rate. Offset interest equivalent: mortgage interest avoided is effectively pre-tax earnings. Higher-rate taxpayer with mortgage at 5.5%: equivalent gross savings rate = 5.5% / 0.6 = 9.17% to match offset b
When Offset Pays Off
Best for: higher-rate taxpayers (greater tax advantage). Variable savings (offset benefit increases as savings grow). Self-employed with VAT or tax savings (use these as temporary offset). Inheritance, bonuses, capital received — accessible while reducing interest. Worst for: low savings (offset rates typically slightly higher than non-offset). Building society members with linked products already getting bonus rates. Anyone needing maximum borrowing — offset products may have lower max LTV. Rat
Offset Provider Considerations
Major UK offset lenders: First Direct (uses overdraft-style flexibility). Yorkshire BS (Offset mortgage, flexible). Family Building Society (Offset). Scottish Widows. Coventry BS. Each has different rules — read carefully: some allow multiple offset accounts. Some restrict to 1-2 accounts. Some allow joint account offset. Some only single named account. Some include current account offset. Most are linked savings only. Overpayment rules: offset mortgages typically very flexible. Overpay any amou
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