Section 8 calculator

Usually about 30 percent of your income after the housing office's deductions, such as a set amount for each child and some childcare and medical costs. This amount is your base payment, the least you pay each month. With no deductions, an income of $2,000 a month gives a base payment of about $600. If the rent plus utilities is above the voucher limit for your area, you also pay the difference. Your base payment plus that difference is your share, what you actually pay.

The voucher pays the voucher limit for your area minus your base payment, and the housing office sends that money straight to your landlord. With a $1,500 voucher limit and a $600 base payment, the voucher pays $900 a month. If the rent plus utilities is lower than the voucher limit, the voucher pays the rent plus utilities minus your base payment instead.

You pay the difference on top of your base payment. But when you first move in, a housing office won't approve a home where you would pay more than 40 percent of your income after deductions. If that income is $2,000 a month, 40 percent is $800.

The voucher limit for your area, officially the payment standard, is the most rent plus utilities the voucher counts for each number of bedrooms. Above it, you pay the difference yourself. Your housing office sets it, starting from Fair Market Rent, the yearly estimate from the federal housing department (HUD) of what a modest apartment rents for in your area. The office's voucher limit can be up to 10 percent higher or lower than that estimate.

The voucher limit is higher for more bedrooms, so a voucher for more bedrooms can pay toward a higher rent. If the home you rent has fewer bedrooms than your voucher, the voucher limit for the smaller size applies.

Your base payment can be $0 if your housing office sets no minimum rent. If it sets one, that minimum is the least you must pay each month, and it can be up to $50. If paying it would be a hardship, you can ask your housing office to excuse you from it. Tell the office when your income changes, because your base payment changes with it.

You can usually take your voucher to another area, even to another state, and the housing office there sets the voucher limit. One exception: if you did not live in the area of the housing office that gave you the voucher when you applied, you must use the voucher in that office's area for your first 12 months, unless the office agrees to let you move sooner. Enter the new ZIP code to see its numbers.