How much rent can you comfortably afford? This calculator checks a rent figure against two common benchmarks — the 30% rule and the 40× annual-income screen letting agents use — and shows what you actually have left each month. It is useful before a flat hunt or a lease signing.
How it works
The tool applies a few exact calculations to your inputs:
- Affordable rent (30% rule) = 30% of gross monthly income (gross annual ÷ 12 × 0.30)
- Rent as a share of gross income = monthly rent ÷ gross monthly income
- Rent as a share of net income = monthly rent ÷ net monthly pay
- 40× screen = pass if gross annual income ≥ monthly rent × 40
- Left over each month = net monthly pay − rent − other monthly debts
The 30% and 40× figures are widely used rules of thumb, not legal limits, so treat the verdict as guidance you adjust for your city and lifestyle.
Example
Gross annual income £48,000 (£4,000/month), net monthly pay £3,000, rent £1,200, other debts £300:
- Affordable rent (30%) = £4,000 × 0.30 = £1,200 → right at the guideline
- Rent share of gross = 1,200 ÷ 4,000 = 30%
- 40× screen = 48,000 ≥ 1,200 × 40 (£48,000) → passes
- Left over = 3,000 − 1,200 − 300 = £1,500/month
| Metric | Value |
|---|---|
| Affordable rent (30%) | £1,200 |
| Rent share of gross | 30% |
| 40× screen | Pass |
| Money left over | £1,500 |
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