How this calculator works

This reverses the standard debt-service test. Lenders start from a maximum acceptable payment (a share of gross monthly income, less existing debts) and work back to a principal amount using the amortisation formula. The result is the ceiling the ratio implies — before credit history, employment, and policy overrides are applied.

A co-signer's income raises the ceiling, which is the main mechanical reason a co-signer helps. But the co-signer also becomes fully responsible for the debt, so the decision is financial and personal, not just arithmetic.

Assumptions and limits

This is an educational estimate produced entirely in your browser. It is not an offer of credit, an approval, or financial advice, and it does not use your real credit file. Lenders apply their own policy, pricing, and verification.