Commercial mortgage calculator

Enter the property value, loan, rate, amortization and term. You'll see the monthly payment, the balloon due when the term ends, and whether the property's income and value support the loan.

By the Calcist team · Checked against known answers · Updated October 28, 2026

Private: calculated on your device. Nothing you type is sent anywhere.

Estimates for planning, not financial, tax or legal advice. Figures use US rules unless the page says otherwise.

Next: Sizing up the property first? The rental property calculator shows NOI, cap rate and cash flow, and the DSCR calculator finds the largest loan the income supports.

How commercial mortgages differ

A commercial loan's payment is often set as if it ran for a long time, such as 25 years (the amortization), but the loan comes due much sooner, such as after 10 years (the term). Whatever is still owed at that point is due in one lump sum, the balloon payment. You'd need to refinance, sell or pay it from cash.

Lenders also size the loan by the property's income and value. The federal banking agencies' real estate lending guidelines ask lenders to set minimum debt-service coverage standards for commercial property, and set a supervisory loan-to-value limit of 85% for improved property. Individual lenders set their own limits.

How it's calculated

Monthly payment = L × i ÷ (1 − (1 + i)⁻ⁿ), n = amortization years × 12
Balloon = balance after (term years × 12) payments
DSCR = NOI ÷ annual debt service · LTV = loan ÷ property value
Largest loan by DSCR = present value of (NOI ÷ minimum DSCR ÷ 12) over n months

Worked example

A $1,400,000 loan on a $2,000,000 property at 6.75%, 25-year amortization and a 10-year term:

Monthly payment: $9,672.76, or $116,073.14 a year.
Balloon due after 10 years: $1,093,079.21.
With NOI of $150,000, DSCR = 150,000 ÷ 116,073.14 = 1.29. LTV = 1.4M ÷ 2M = 70%.
With a 1.25 minimum DSCR, the largest loan the income supports is about $1,447,363; a 75% LTV allows $1,500,000. The smaller one, the DSCR limit, binds.

Same $1.4M at 6.75%, 25-year amortization	Balloon due
5-year term	$1,272,122
7-year term	$1,207,639
10-year term	$1,093,079

Limitations

Many commercial loans have interest-only periods, prepayment penalties, yield maintenance or defeasance. Those aren't modeled.
NOI is income after operating expenses but before loan payments. Lenders often underwrite their own, lower NOI.
Some lenders count interest on an actual/360 basis, which makes payments a little higher than this monthly math.
To work out NOI and cap rate for a rental, use the rental property calculator.

Sources

Federal Reserve: Interagency Guidelines for Real Estate Lending Policies (supervisory LTV limits)

How we checked this

Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:

$1.4M at 6.75%, 25-year amortization: $9,672.76 a month ✓
Same: balloon of $1,093,079.21 due after 10 years ✓
Same: DSCR 1.29 and LTV 70% ✓
Same: DSCR limits the loan to about $1,447,363 ✓
$800,000 on $1M with $80,000 NOI at 7%: DSCR 1.07 fails a 1.25 minimum ✓
Term equal to the amortization: no balloon ✓

Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.

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Questions people ask

How is a commercial mortgage payment calculated?

Like any amortizing loan, but over the amortization period rather than the term. $1.4 million at 6.75% amortized over 25 years is $9,672.76 a month.

What is a balloon payment on a commercial loan?

The balance still owed when the term ends. On the loan above with a 10-year term, it's $1,093,079.21.

What is DSCR?

Debt service coverage ratio: the property's net operating income divided by the yearly loan payments. 1.29 means the income covers the payments 1.29 times.

What LTV do commercial lenders allow?

It varies by lender and property. Federal supervisory guidelines set an 85% loan-to-value limit for improved property, and lenders often set their own lower limits.

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