Legacy Investing CalculatorsShow

Payment-based borrowing limit

What principal fits a chosen payment, rate, and term?

Your numbers

$
%
yrs

Borrowing limit

$25,589

Total paid over the term$33,000
Interest included$7,411
Payments60 months

Tip. Leave margin under the maximum so taxes, insurance, and maintenance still fit.

Assumptions

  • Solves for the principal from the standard amortization payment formula, so it is the exact inverse of a loan payment calculation.
  • Principal and interest only. Property tax, insurance, and any mortgage insurance sit on top of the payment you enter.
  • This is a payment-affordability limit, not an approval. Lenders also weigh credit history, debt-to-income, and reserves.

Explore the numbers

Examples and charts

Start with a scenario, then read the response curve to see which input actually moves the answer.

Example 1

Car loan budget

A comfortable payment over a five-year term at a typical auto rate.

Borrowing limit

$25,589

Example 2

Personal loan budget

A smaller payment over three years, where the principal it supports is modest.

Borrowing limit

$9,032

Example 3

Mortgage principal from a payment

What a housing payment supports over thirty years, before tax and insurance.

Borrowing limit

$379,706

Sweeps target monthly payment from half to one and a half times your value, holding everything else fixed.

Response curve

How target monthly payment moves the result

Borrowing limit

$25,589

$15k$20k$25k$30k$35k$40k$300$400$500$600$700$800
Chart axis: Target monthly paymentNow $550 → $26k

What this calculates

Works backwards from a payment you can comfortably afford to the principal that fits it at a given rate and term.

How to use it

  1. Start with target monthly payment and work down the form, or load an example to begin from a realistic case.
  2. Read the headline result alongside the supporting rows, which show the intermediate figures behind it.
  3. Check the assumptions. They decide what the number includes and, more importantly, what it leaves out.
  4. Sweep target monthly payment on the response curve to see how much it actually moves the answer.
  5. Run a cautious case as well as an optimistic one before using the estimate in a decision.

Common mistakes

  • Maxing the payment with no emergency-fund buffer left.
  • Solving for the limit at a promotional rate you will not actually receive.
  • Forgetting that the limit is the loan, not the purchase price, since the down payment sits on top.

Formula

Solve P from the standard amortization payment equation

Inputs

  • Target monthly payment
  • APR (%)
  • Term (yrs)

FAQ

Is this how a lender approves me?

No. Approval also runs on credit history, debt-to-income, and residual income. This only sizes the principal that the payment mathematically supports.

Does this include tax and insurance for a mortgage?

No. It solves for principal and interest only. On a home, budget roughly 20 to 30% of the housing payment for escrow and upkeep before setting the payment you enter here.

Why does a longer term barely raise the limit at a high rate?

Because at higher rates a growing share of each payment covers interest rather than principal. Sweep the term field and watch the curve flatten.

Are these numbers financial advice?

No. They are educational estimates based on the inputs and assumptions on this page. Confirm important decisions with a qualified professional and your own documents.

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