Loan Calculator by Monthly Payment
How much can you borrow for a target payment?
Budget-first math on your device — no sign-up, no uploadYour payment breakdown appears here
Fill in the loan details and press Calculate — the monthly payment, total interest and schedule will render right on this page, with nothing sent to any server.
How to use
Most calculators ask how much you borrow. This one flips the question: you know what you can pay each month, so it returns the maximum loan amount that payment supports at a given rate and term — the budget-first way to shop.
How to use
- Enter the monthly payment your budget allows.
- Set the APR and the term in years.
- Press Calculate to see the maximum loan amount.
Example
You can afford $400 a month. At 6% for 5 years that supports a loan of about $20,690. At 8% the same $400 supports only about $19,720 — each point of rate costs roughly $500 of buying power on this budget.
Formula
The present-value formula inverted: P = PMT · ((1+r)^n − 1) / (r·(1+r)^n). It is the exact inverse of the monthly payment formula.
Budget-first shopping
Dealers quote payments; your budget should set the limit. Fix the payment, let the calculator move the amount, and walk in knowing the ceiling for your monthly number.
Term is a lever
Stretching from 5 to 6 years lifts the affordable amount by roughly 17% on the same payment — but adds interest. Use the term lever for flexibility, not for buying more than you planned.
Dealer payment games
Salespeople often ask what payment you want and then stretch the term to hit it. That trick hides the price of the car. Fixing the payment here, at a term you chose, keeps the negotiation about the actual price — not about a monthly number shaped by an 84-month financing plan.
FAQ
Stay within budget?
This tool keeps the payment fixed, so you never exceed the monthly number you decided on.
How much does a rate point matter?
On a 5-year loan, each point of rate shifts the affordable amount by roughly 4-5% — about $500 per point at the $20,000 level.
Does a longer term buy more?
Yes, but with more interest — the calculator shows the amount, and the interest tool shows the cost.
Is this useful before visiting a dealer?
Very — it turns your budget into a hard ceiling you can defend against payment-based sales talk.
Reviewed by the LoanMath editorial team