Use the free Rent Affordability Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server. Results are estimates only.
The 30% rule, explained simply
Housing experts have long used a simple guideline: spend no more than 30% of your gross monthly income on rent. Gross income means before tax, not after. So if you earn $4,000 a month before tax, the rule suggests rent of no more than $1,200. Households spending more than 30% are often described as cost-burdened, because housing leaves too little for food, transport, savings, and everything else.
The rule is popular because it is easy to remember and easy to apply, and many landlords use a version of it when screening tenants. Some ask for income of three times the rent, which is exactly the same rule in reverse. But a guideline is not a law of nature: it is a starting point, and your real affordable rent depends on your debts, your bills, and the cost of living where you live.
How this calculator works
Enter your gross monthly income and choose a budget rule: 25%, 30%, or 35%. The tool multiplies your income by the rule to give your affordable rent. You can also enter a rent you are considering, and the tool shows what percentage of your income it takes and whether it fits the rule you chose. For example, $1,300 of rent on $4,000 of income is 32.5%, which breaks the 30% rule but fits the 35% rule.
Use the result as a ceiling for your search, not a target. Just because you can afford $1,200 does not mean you should spend $1,200. Every dollar below the ceiling is a dollar for savings, debt repayment, or breathing room when something unexpected happens.
When 30% is too much, or too little
The rule fits best for middle incomes in average-cost areas. If you carry heavy student loans, car payments, or medical bills, even 30% may be too much, because those fixed payments compete for the same income. In that case, 25% is a safer ceiling, and it leaves room to pay down debt faster.
On the other hand, in expensive cities, sticking to 30% can mean a long commute or an unsafe area, and many people reasonably stretch to 35% or more. High earners can also stretch further, because 40% of a large income still leaves plenty for other spending, while 40% of a small income leaves almost nothing. The percentage matters less than the absolute amount left over after rent and bills.
The number that matters more: what is left over
After you find your affordable rent, subtract your other fixed costs: utilities, transport, food, insurance, debt payments, and a savings contribution. If what remains is thin or negative, the rent is too high for you, whatever the rule says. This leftover test is more honest than any percentage, because it uses your real life instead of an average household.
Be especially careful with costs that renters forget: utilities if they are not included, parking, laundry, internet, and renter’s insurance. A rent that looks affordable can become unaffordable once those are added, so price the full monthly cost of the home, not just the rent line on the listing.
Gross income versus take-home pay
This calculator uses gross income, following the standard rule. But your take-home pay is what actually lands in your account, and taxes can take a large share. If your tax burden is heavy, you may prefer to apply the rule to your take-home pay instead: enter your after-tax monthly income and use the same 30% figure for a more cautious ceiling. The calculator works either way; what matters is that you know which income figure you entered.
Variable income needs the same caution. If you are freelance or commission-based, use an average month, not your best month, and keep a buffer for slow months. A rent set from a peak month becomes a burden in an ordinary one.
Using the result in a real search
Set your listing filters to your affordable ceiling before you start browsing, and do not let a beautiful apartment talk you into breaking it. Landlords and agents benefit when you stretch; you live with the payment. If nothing decent fits your ceiling, consider a roommate, a different neighborhood, or a smaller place rather than quietly accepting a rent that will strain every month.
Finally, revisit the number whenever your income changes. A raise should not automatically mean a bigger apartment: holding your rent steady while your income grows is one of the fastest ways to build savings and financial security.
Disclaimer: All results are estimates only and are not financial or tax advice. Check with a qualified professional before making financial decisions.
All results from this calculator are estimates based on the income and rule you enter. They are not financial or tax advice, and your real budget depends on your full spending.
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