Rent Affordability Calculator

The 30% Rule, and Where It Breaks

The threshold comes from US housing policy: households spending more than 30% of income on housing are formally classified as cost-burdened. It is a reasonable default and a blunt instrument. It ignores your debts entirely, it ignores that taxes take a bigger bite at higher incomes, and 30% of $30,000 leaves far less room than 30% of $150,000.

Three Numbers Worth Knowing

The 40x test is the same idea from the other side of the table: many landlords require annual gross income of at least 40× the monthly rent. Some use 3× monthly income instead, which is slightly more generous. If you fall short, the usual remedies are a co-signer or guarantor, a larger deposit where state law allows, or prepaid rent.

What Rent Does Not Include

The advertised rent is rarely the monthly cost. Budget separately for:

• Utilities — electricity, gas, water, trash, internet. Ask which are included; it can swing $100–300 a month.
• Renters insurance — often required by the lease, and inexpensive.
• Parking, pet rent, laundry, storage — commonly billed on top.
• Move-in cash — deposit plus first month, sometimes last month too, plus moving costs.

Renting right at your maximum is the classic mistake: it leaves nothing for the deposit that gets you the apartment, and nothing for the month something goes wrong.

Sharing a Place Changes the Math

Splitting with roommates is the fastest way to move a place into range — but only if the split is agreed properly, especially when bedrooms differ in size. The rent split calculator handles that, and note that most shared leases are joint and several — meaning you are liable for the whole rent if a roommate stops paying, not just your share.

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