Oklahoma has an effective property tax rate of about 0.85% of home value, which on the statewide median price of $215,000 works out to roughly $152 a month before you touch principal or interest.
Homeowners insurance averages about $4,100 a year here, or $342 a month. Tornado alley exposure makes insurance one of the highest nationally.
The top marginal state income tax rate is 4.75%, which reduces take-home pay and so lowers the payment a lender will approve. The calculator above starts from these statewide figures — replace them with your actual county's rate and a real insurance quote as soon as you have them.