Mortgage Calculator

How it works

Comparing mortgage payments and ownership costs

A mortgage payment is only one part of the cost of owning a home. Compare the principal and interest payment with the ownership-cost worksheet before deciding what fits your monthly budget. Changing the down payment changes the amount borrowed, while changing the term spreads repayment over a different period. Keep the purchase price and interest-rate assumptions consistent when comparing scenarios.

Guides

• What your mortgage payment actually includes

  Understand principal, interest, ownership costs, and why a loan payment is different from a full housing budget.

US mortgage: formula and assumptions

Loan = price × (1−down payment%). Monthly payment = Pr/[1−(1+r)^−n].

The schedule assumes a fixed interest rate over the entered amortization period. Ownership costs are tracked separately from loan principal and interest.

Calendar-based extra payments: formula and assumptions

Payment = principal / annuity present-value factor. Each month applies interest, scheduled payment, then extras.

Monthly, annual and dated one-time extras are combined. The final payment is capped at the debt owed. Compare the actual payoff and interest with an unchanged-payment baseline.

Down payment & ownership-cost worksheet: formula and assumptions

Year y cost = normalized first-year cost × (1+its growth)^(y−1).

Percent costs use original price, with growth applied once to the cost. This worksheet separates ownership expenses from loan principal and interest.

Accelerated biweekly with balance inference: formula and assumptions

Accelerated installment = monthly payment / 2. Interest factor per interval = (1+APR/12)^(12/26).

This uses 26 equal interest periods per year. Current principal may be inferred from original terms or a payment/remaining-term pair. Loan-servicer collection and posting can differ.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the US mortgage example:

Home price ($)

400000

Down payment (%)

20

Annual interest rate (%)

6.5

Term (years)

30

Annual property tax ($)

3600

Annual home insurance ($)

1200

Monthly mortgage insurance ($)

0

Monthly HOA fees ($)

0

Other monthly ownership costs ($)

0

Annual tax increase (%)

0

Annual insurance increase (%)

0

Annual HOA increase (%)

0

Extra monthly principal ($)

0

Extra annual principal ($)

0

One-time extra principal ($)

0

One-time payment month

12

First payment month

2026-11-01

Loan = price × (1−down payment%). Monthly payment = Pr/[1−(1+r)^−n].

Example result

• Ownership cost excludes extra principal payments. Insurance input stays constant except for the entered growth; mortgage-insurance cancellation is not automatic.

These are illustrative inputs. Change the values to explore a different scenario.

What to keep in mind

This is an estimate, not a loan offer. Taxes, insurance, mortgage-insurance cancellation, renewal terms, and fees depend on your agreement.

Formula references

• CFPB: understanding mortgages (opens in a new tab)
• Investor.gov: financial tools and calculators (opens in a new tab)
• OpenStax loan amortization (opens in a new tab)
• CFPB mortgage terms: biweekly payments (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions