How Rent Affordability Is Calculated

概要

Rent affordability is about working out how much of your income you can realistically spend on rent while still covering bills, commitments, and savings. There is no single “correct” answer — different rules of thumb suit different situations. This calculator applies four common approaches and shows you the range, so you can make an informed decision.

仕組み

The calculator uses four affordability rules, from most generous to most conservative:

1. 30% of gross income — the traditional guideline used by letting agents and landlords. Simple to calculate, but doesn’t account for tax, commitments, or savings.

2. 30% of net income — a more realistic version recommended by financial advisors and MoneyHelper. Uses your actual take-home pay after income tax and National Insurance.

3. Landlord referencing check — most UK landlords and letting agents require your annual salary to be at least 2.5 times the annual rent (equivalently, annual salary divided by 30 gives the maximum monthly rent). If you don’t meet this threshold, you may need a guarantor.

4. Budget-based — takes your net income, subtracts your existing commitments (loans, credit cards, subscriptions) and savings goal, then recommends spending no more than 50% of what’s left on rent. This is the most personalised approach.

The formulas

Landlord referencing: the 2.5x rule

Most UK letting agents use a standard affordability check during tenant referencing: your gross annual income must be at least 2.5 times the annual rent. This is equivalent to saying your annual income should be at least 30 times the monthly rent.

For example, if a flat costs £1,000/month (£12,000/year), you need to earn at least £30,000/year to pass the check. If you don’t meet this threshold, landlords may ask for a guarantor (who typically needs to earn 3x the annual rent).

Worked examples

入力値の説明

• Gross annual salary — your total annual salary before any deductions. The calculator uses UK 2025/26 income tax and National Insurance rates to derive your net income.
• Monthly commitments — regular outgoings you can’t avoid: loan repayments, credit card minimums, car finance, subscriptions, childcare, etc.
• Monthly savings goal — how much you want to save each month. This is subtracted before calculating the budget-based figure.

出力値の説明

• 30% of gross — the traditional “rule of thumb.” Easy to calculate but doesn’t reflect your actual spending power.
• 30% of net — a more realistic ceiling based on take-home pay.
• Landlord max rent — the maximum rent a landlord would accept you for without a guarantor, based on the 2.5x referencing standard.
• Budget-based rent — the most personalised figure, accounting for your actual commitments and savings goals.
• Conservative recommendation — the lowest of the four figures, shown as a suggested maximum.

前提条件と制限事項

• Tax calculation uses 2025/26 UK income tax and National Insurance rates (personal allowance £12,570, basic rate 20%, NI at 8%). Does not include student loan repayments or pension contributions.
• The 30% rule is a guideline, not a hard limit. In expensive cities like London, many renters spend 40–50% of income on rent. The ONS reports that UK renters spend an average of 41% of take-home salary on rent (2024 data).
• The landlord 2.5x check is the most common referencing standard but not universal — some agents use 2.0x or 3.0x.
• The budget-based approach uses 50% of available income as the rent ceiling. This is a conservative default; some frameworks use different splits.
• Does not account for housing benefit, Universal Credit housing element, or other benefits that could increase affordability.
• Does not model shared tenancies where rent is split between multiple occupants.

検証