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How much should I spend on a mortgage each month?
Lenders commonly use 28/36: housing costs under 28% of gross income and all debt payments under 36%. That is a threshold for the lender's risk, not for your comfort. Budget the full carrying cost instead, which is principal and interest plus property taxes, homeowners insurance, any PMI and HOA, and a maintenance line, and keep that total under roughly 30% of take-home pay. The payment and the irregular costs need two separate envelopes.
What a lender quotes is not what leaves your account
Principal and interest is the number in the ad and the number your loan officer says out loud. It is rarely more than part of what you actually pay. Add property taxes and homeowners insurance, which usually come through escrow and get re-estimated every year, so your payment moves even on a fixed-rate loan. Add private mortgage insurance if your equity is below the threshold your loan type requires. Add HOA or condo dues if the property has them, which are not part of the mortgage at all and can be raised by a vote you do not control. Then add maintenance, which no lender counts and no calculator shows, because it does not affect their risk. Their number and your number are answering different questions.
Where 28/36 comes from and what it is for
The 28/36 guideline is underwriting shorthand: keep the housing payment under 28% of gross monthly income and total debt payments including the mortgage under 36%. It exists because lenders needed a consistent screen for default risk, and it has been durable for decades in conventional lending, with plenty of programs that allow higher ratios. Read it correctly and it tells you the largest loan an institution is willing to be repaid on. It says nothing about whether you can also fund retirement, childcare, a car that will eventually die, or a roof that is fifteen years old. Being approved is not the same as being able to afford it. Use 28/36 to understand what you will be offered, then run your own test before you decide what to take.
Rerun the test on take-home pay
Do the same arithmetic against the money that actually reaches your account. Add up principal, interest, taxes, insurance, PMI and dues, then add a monthly maintenance figure. A common convention is one percent of the home's value per year divided by twelve, but that is a rule of thumb rather than a measurement. The better version, once you own the place, is your own repair history: total everything the house cost you over the last three years and divide by thirty-six. Keep that full number under roughly 30% of take-home and the rest of the budget stays breathable; above 40%, the house is running you. Carry less than the band with an older home, variable or commission income, childcare or student loans, and more when the house is new, your income is stable and you have no other debt payments.
The two envelopes homeowners actually need
One envelope covers what leaves on the same day every month: the mortgage payment as your servicer bills it, escrow included. The second is a sinking envelope that fills every month and is spent irregularly, and it holds maintenance, any taxes or insurance you pay directly rather than through escrow, an escrow shortage when the annual analysis comes back higher, and the deductible you would need to start an insured repair. The first envelope is boring on purpose. The second is the one that decides whether a water heater is a Saturday or a crisis. Most people who feel house-poor have funded only the first, so every genuinely normal homeownership cost arrives looking like an emergency and lands on a credit card.
The envelope change to make this week
Open the last twelve months of your bank activity and pull out every dollar the house consumed that was not the monthly payment: repairs, appliances, pest control, gutters, tools, the plumber, the escrow adjustment. Divide by twelve. That figure, not one percent of anything, is what your Home Maintenance envelope should receive each month starting now. Keep it apart from the Mortgage envelope so a good year visibly accumulates instead of quietly being spent. In Envelope Budget you can point a savings goal at that envelope and watch the balance grow between repairs, which is the whole reason it works. If the two envelopes together will not fit inside 30% of your take-home, you have learned something important before the roof does.
Common questions
Does the 28/36 rule use gross or net income?
Gross. Underwriting ratios are calculated on pre-tax income because that is what a lender can verify consistently across borrowers. That is exactly why the rule feels tighter than it sounds once you live inside it, since your actual money arrives after taxes, health premiums and retirement contributions. If you want a comfort test rather than an approval test, redo it on take-home pay, include maintenance, and aim for roughly 30% or less. Expect the approval number and the comfort number to be meaningfully different, and expect the gap to be larger the higher your tax and benefit deductions run.
How much should I budget for home maintenance?
The common rule of thumb is one percent of the home's value per year, and it is a starting point rather than a fact about your house. Age, climate, roof and system life, and whether you do work yourself all move it substantially. The honest number is your own: add up everything you spent on the property over the last two or three years, including appliances and one-off projects, and divide by the number of months. Fund that into a separate sinking envelope monthly. If you have not owned long enough to have a history, start at the rule of thumb and correct it after a year.
Is a mortgage payment better than rent because of equity?
Equity is real, but it does not appear in your monthly cash flow, and your budget runs on cash flow. Owning also transfers costs to you that a landlord previously carried, including repairs, appliance replacement, insurance and taxes. The right budgeting comparison is total monthly outlay against total monthly outlay: rent plus renters insurance versus payment plus escrow plus dues plus maintenance. Whether the equity makes up the difference depends on how long you stay and on things nobody can promise you. Budget the cash, and treat the equity as a separate question.
Run this budget on your phone
Envelope Budget puts these envelopes in your pocket. Assign every amount, log spending as it happens, and see what is actually left.
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