Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
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Use this result
Share the current inputs or ask ChatGPT to explain the calculation in context.
What does this calculator estimate?
$72,000/year is $6,000/month; at the 30 percent rule, rent up to $1,800/month is affordable. Suggested rent = the lower of the income-rule cap and the cash-based cap.
- The 30 percent rule caps rent at 30 percent of gross monthly income (Wikipedia).
- Gross monthly income = annual income / 12.
- The cash-based cap subtracts debts and savings from gross income.
How rent budgets are set
The classic guideline is spending no more than 30% of gross income on rent. A better check adds cash flow: rent plus debts and savings must fit the actual budget. The calculator applies both and recommends the conservative number.
Limitations to watch for
The 30% rule is a guideline, not law — high-cost cities often exceed it, and 25% is more comfortable. Landlords typically require income at 3× the rent. The tool doesn't model utilities, renter's insurance, or rent growth.
How to use it in practice
Use your take-home reality: list debts and savings goals, then see what rent leaves you comfortable. Keep rent under the 30% cap and the cash-based cap. Re-check when income or debts change.
['Enter annual income.', 'Enter monthly debts and savings goals.', 'Read the income-rule and cash-based caps.']
The 30 percent rule
The classic guideline: spend no more than 30 percent of gross income on rent. At $72,000 annual gross ($6,000 monthly), the ceiling is $1,800. The rule is a lender-style screen — your real budget depends on debts, savings, and local costs, which the calculator's debt and savings inputs capture.
Gross vs. take-home income
The 30 percent rule uses gross income, but budgets run on take-home. At 25 percent effective tax, $6,000 gross becomes $4,500 take-home — 30 percent of gross is 40 percent of take-home. The calculator shows both views so the number matches the paycheck that pays the rent.
The debt-adjusted ceiling
A common stricter version caps housing at 30 percent and total debt (housing plus other payments) at 36 percent of gross. With a $500 car payment, the housing ceiling drops to about $1,660 on $6,000 gross. The calculator applies the debt subtraction so the result is personal.
Local reality beats national rules
In high-cost cities, 30 percent is often unattainable without a roommate; in low-cost areas, spending 25 percent is normal. The rule is a starting point — compare your number against local market rents and your actual spending history.
A worked example
$5,500 gross monthly, $400 in car and loan payments, 30/36 rule: housing ceiling = $1,650 (30%), total debt ceiling $1,980 minus $400 = $1,580 — the tighter constraint is about $1,580. The calculator computes both ceilings and flags which one binds.
How this calculator works
Formula
Gross monthly income = annual income ÷ 12. Income-rule cap = gross × target % (usually 30%). Cash-based cap = gross − monthly debts − savings. Suggested rent = the lower of the two caps.
Worked example
$72,000/year = $6,000/month; at the 30% rule, rent up to $1,800/month.
Assumptions to verify
- The 30% gross-income guideline applies.
- Debts and savings are entered monthly.
- Utilities and insurance are separate.
Frequently asked questions
How much rent can I afford?
The standard rule: no more than 30% of gross income. At $72k/year that's $1,800/month.
What is the 30% rule?
A guideline that housing costs shouldn't exceed 30% of gross income — 25% is even more comfortable.
Do landlords use 3× income?
Many require gross monthly income at least 3× the rent — the other side of the same rule.
What if I have debts?
The cash-based cap subtracts debt payments and savings from your income — use the lower of the two caps.
Does this include utilities?
No — add utilities, internet, and renter's insurance to the rent for the true housing cost.
Can I exceed 30% in expensive cities?
Often necessary — but the cash-based cap shows what you can actually sustain. Cut elsewhere.
How do I negotiate rent?
Compare comparable units, offer longer terms, and move in off-peak seasons — but start from what you can afford.
Is 30% of gross or take-home?
The rule uses gross; your real budget should also be checked against take-home.
Do debts reduce the rent ceiling?
Yes — the 36% total-debt version subtracts other payments from the housing allowance.
What if 30% is impossible in my city?
Adjust the rule to reality, but keep total debt service manageable and track actual spending.
Cite this tool
BoringToolsKit. “Rent Affordability Calculator.” boringtoolskit.com/rent-affordability-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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