A practical guide to moving up
Two numbers: what a lender will approve, and what fits your cash flow
A pre-approval letter answers one question: how much will this lender let you borrow? It is built from gross income, your existing debt payments and the new mortgage payment, measured against ratios the lender considers acceptable, commonly around 28% of gross income for the housing payment and 43% for all debts together. Those tests do not see what you take home after taxes and retirement contributions, what you spend on children, cars, travel and food, or how much you want to keep saving. They also stop at the mortgage, taxes, insurance and HOA; maintenance, higher utilities and furnishing a bigger house sit outside them.
That is why the calculator above gives you both numbers. The lender's view is labelled as typical guidelines, because every lender differs. The cash-flow view answers the question you actually care about: the highest price at which your household still keeps a cushion every single year. Knowing both before you start looking means you can set your own ceiling rather than discovering it later.
What moving up costs, at closing and every month
Moving up costs money twice: once at closing and then monthly for as long as you own the house. At closing, selling your current home typically costs around 6% of its price in commissions, closing fees and the repairs and staging it takes to sell well. Buying costs another few percent in lender fees, title and escrow. Moving and furnishing a larger house is rarely under five figures. All of that comes out of the equity you are counting on for the down payment, which is why the calculator works out the net proceeds and the cash needed at closing before it does anything else.
Then the monthly cost. The mortgage payment is the headline, and on a higher-priced home the other lines grow with it: property tax is a percentage of value, insurance follows the rebuild cost, and maintenance scales with square footage and age. A rule of thumb of 1% of the price per year for upkeep is generous for a newer home and about right for an older one. If the down payment lands under 20% of the price, private mortgage insurance adds a line until the loan falls below 78% of the purchase price. The calculator adds all of these to the mortgage payment to get the full monthly housing cost, then compares it with what you pay today, so the change is a concrete figure rather than a guess.
Property taxes and insurance
Property tax rates vary widely by state, county, city and school district, and the number that matters is the one for the specific address you are considering, not a state or national average. The best source is the county assessor or appraisal district and the taxing units listed on last year's bill for that property. In many places a sale resets the assessed value to something close to the purchase price, so plan on your own bill being higher than the previous owner's.
Homeowners insurance has risen in many regions in recent years, and premiums on larger homes can be a meaningful share of the monthly cost. A real quote for the address, obtained before you make an offer, is worth more than scaling up your current premium. The calculator grows both taxes and insurance a little faster than general inflation by default, so a plan that is Comfortable in year one is shown with the realistic year-five and year-six figures as well.
Buying before selling
Carrying two homes for a few months is a common and workable way to move, and it changes the cash you need at closing. If you buy first, the proceeds from your current home are not available for the down payment on the day you close, and you pay two housing costs until the old home sells. The calculator handles the simple version of that: it adds the months of overlap to your cash at closing and tells you if the total exceeds the equity and savings you have. It does not model bridge loans or contingent offers, so treat a warning as a prompt to ask a lender how the gap would be financed, not as a sign that it cannot be done.
Questions worth settling before you list
Which number are we planning around? If the cash-flow maximum is below the lender maximum, decide together which one is your ceiling before you start touring. Most households find the cash-flow number is the one they are glad they used.
How much room do we want in the tightest year? Look at the year with the smallest margin in the full forecast. If a car repair or a smaller bonus would use it up, that is a Tight plan, and it is a reasonable plan as long as you both choose it knowingly.
What if the rate is a point higher? Rates move between pre-approval and closing. The alternative plan with a rate one point higher shows how much that alone changes, so you know in advance whether a rate move changes the decision.
Where does the closing cash come from? Equity becomes cash when the sale closes. If you are buying first, have the gap financed on paper before it needs to be financed in practice.
What do our real accounts say? This calculator works from estimates you typed in. Households that make this decision well check those estimates against what actually leaves their accounts each month, how uneven the year is, and what is genuinely left after everything clears. That is the job Finance Forecaster was built for.