How much rent can you comfortably afford? This calculator starts from your income, applies an adjustable rent rule (the classic 30% by default), subtracts your real monthly expenses and a savings target, and returns a recommended maximum rent you can actually sustain. It is built for the moment before a flat hunt or a lease signing, when a single percentage is not enough and you want a number that respects your existing commitments. Every figure is currency-agnostic — pick your currency or use whichever fits your market — and nothing ever leaves your browser.
Two ceilings, one recommendation
Most rent guidance stops at one number — “spend 30% of your income”. That is a useful anchor, but it ignores the loans, bills and savings goals that already claim part of your pay. This tool models both views and is deliberately conservative:
- Percentage ceiling = your chosen rule percent applied to income. You decide whether that income is net take-home or gross pre-tax.
- Cashflow ceiling = spendable income (net monthly plus any other monthly income) minus the sum of your listed commitments minus your savings target.
- Recommended maximum rent = the lower of those two ceilings, so the result is never higher than your real budget allows.
- Rent-to-income ratio = recommended rent divided by spendable income, colour-coded comfortable, stretched or risky.
The tool also tells you which ceiling is binding — the percentage rule or your cashflow — so you know whether the limiting factor is the guideline or your actual outgoings. A doughnut chart splits your spendable income into recommended rent, other expenses, savings and the remaining cushion.
Example
Suppose your net monthly income is 2,800 with no other income, you keep the rule at 30%, you save 10%, and your monthly commitments are 200 debt, 250 utilities, 350 food and 150 transport (1,000 total).
- Percentage ceiling = 2,800 times 30% = 840
- Savings set aside = 2,800 times 10% = 280
- Cashflow ceiling = 2,800 minus 1,000 expenses minus 280 savings = 1,520
- Recommended maximum rent = the lower of 840 and 1,520 = 840
Here the 30% rule is the binding limit — your cashflow could stretch further, but the guideline keeps you comfortable at a 30% rent-to-income ratio. If your commitments rose to 2,000, the cashflow ceiling would fall to 520 and become the binding limit instead, pulling the recommendation well below the percentage rule.
| Input | Recommended max rent | Binding ceiling |
|---|---|---|
| 2,800 income, 30% rule, 1,000 expenses | 840 | 30% rule |
| 2,800 income, 35% rule, 1,000 expenses | 980 | 35% rule |
| 2,800 income, 30% rule, 2,000 expenses | 520 | cashflow |
Note on the formula: the recommendation is min(income × rule%, income − expenses − savings).
Where the 30% rule actually comes from
The 30% figure is not arbitrary — it is a U.S. housing-policy standard with a paper trail. The 1969 Brooke Amendment capped public-housing rents at 25% of tenant income; Congress raised that cap to 30% in 1981, and the U.S. Department of Housing and Urban Development has used 30% ever since as the threshold above which a household counts as “cost-burdened” — spending more than 30% of income on housing (see HUD’s affordable-housing definitions). Households above 50% are “severely cost-burdened”.
Two things follow. First, the rule was designed as a protection ceiling, not a spending recommendation — landing under it is the point, not hitting it. Second, it is a population-level policy line, so your personal ceiling can reasonably differ: a high earner with no debt can safely exceed 30%, while someone with student loans and childcare may be stretched at 25%. That is exactly why this calculator computes the cashflow ceiling alongside the rule.
How landlords will assess you (and why it differs)
Letting agents and landlords screen the other way round — from the rent to the income. In the UK, referencing checks commonly look for gross annual income of roughly 30 times the monthly rent (about 40% of gross income going to rent); the UK government’s official How to Rent guide describes the referencing and affordability checks tenants should expect. In the U.S., a gross-income multiple of 40x monthly rent (i.e. rent ≤ 1/40 of annual income) is the common New York standard, and 3x monthly income elsewhere.
The practical implication: you may pass a landlord’s affordability screen for a rent that this calculator flags as risky, because screening uses gross income and ignores your actual outgoings. Treat the screening threshold as what you can be approved for, and the cashflow ceiling here as what you can sustain.
Squeezing the most out of the result
- Run it twice — gross basis and net basis. The gap between the two numbers is roughly your tax and deductions; if a rent only “works” on the gross basis, it will feel tight every single month.
- Stress-test the cushion. After rent, expenses and savings, aim for a remaining buffer that could absorb a one-month income gap. If the doughnut chart shows a sliver, consider the next rent band down.
- Don’t zero the savings target to afford more rent. A savings rate of even 5–10% is what keeps a car repair or deposit-to-deposit move from becoming debt.
- Recheck at renewal. Rents move; incomes move. Two minutes with updated numbers tells you whether a proposed increase keeps you inside your bands.
Every number is calculated in your browser — nothing is uploaded or stored.