House Affordability Calculator
Strict 28/36 DTI rule — front-end housing ratio and back-end total debt ratio.
100% Secure. Calculations run locally — your data never leaves your browser.
$
$
Car, student loans, min. credit-card
%
$
yr
%
$/yr
Max home price (28/36 DTI)
$365,130.23
Limited by front-end (28%) · housing budget $2,380.00/mo
Monthly PITI
$2,380.00
P&I $1,928.63 · T $334.70 · I $116.67
Front-end DTI
28%
Housing ÷ income (cap 28%)
Back-end DTI
33.3%
All debt ÷ income (cap 36%)
DTI ratio gauge
Front-end (housing)28% / 28%
Back-end (total debt)33.3% / 36%
Affordability — answers & formulas
Deep-dive formulas, definitions, and worked examples — indexed for search and ready to share.
Math HistoryFrance · 1642
The 17th-Century Tax Crisis
An 18-year-old French math prodigy named Blaise Pascal grew tired of watching his father labor over grueling, manual tax bookkeeping. To solve the problem, he invented the Pascaline—the world's first operational mechanical calculator. It executed addition and subtraction using a complex internal system of interlocking clock gears and brass wheels, hand-turned via a metal stylus.
0 / 4