METHOD
Formula and method
New payment = max(0, income × ratio − existing payments).
Translate your chosen repayment budget into a possible principal amount.
Starting values are an example. Replace them with your own.
Your inputs stay in your browser.
Enter your details and run the calculation.
Informational calculations. Check assumptions, dates and jurisdiction before making a decision.
Full disclaimerThe calculator takes the share of net income you are willing to spend on all repayments, subtracts existing repayments and treats the rest as a new monthly payment. From that payment, the interest rate and the term it works out the principal that payment would repay. It is a rough answer to how much you could borrow on your budget, while a bank assesses creditworthiness separately with its own rules and living costs. The starting 30% is your assumption, not a legal limit.
METHOD
New payment = max(0, income × ratio − existing payments).
TRACEABLE
Basic arithmetic or geometry using the formula shown. Uses only your inputs.
How we maintain data