HELOC Payment Calculator

About this calculator

A free HELOC calculator that answers the three questions in order: how big a line your equity supports, what a draw costs per month while the line is interest-only, and what the payment becomes when the draw period ends and the balance amortizes. Drawing $50,000 at 8.5% costs $354.17 a month in interest; the same balance repaid over 15 years costs $492.37 a month. HELOC rates are variable, so every figure holds the rate you enter constant and is a planning estimate — not a credit decision, an offer of credit, or financial advice.

How lenders size a HELOC line

Lenders cap your combined loan-to-value — the first mortgage plus the HELOC line, divided by the home's value — usually somewhere between 80% and 90%. The calculator multiplies your home value by that cap and subtracts what you still owe: a $400,000 home at an 85% CLTV cap supports $340,000 of total borrowing, and with a $250,000 mortgage outstanding that leaves a $90,000 line. The same home with a $320,000 balance leaves only $20,000, which is why recent buyers with small down payments often can't open a meaningful line yet.

Your equity — value minus balance — is a bigger number than your borrowing power ($150,000 vs $90,000 in the example), because the CLTV cap deliberately leaves a cushion. Appraisals, credit, and income still decide the real approval; the calculator shows the collateral math that bounds it.

The draw period is the cheap phase

Most HELOCs open with a 5–10 year draw period in which the minimum payment is interest only. That makes carrying a balance look deceptively light: $50,000 drawn at 8.5% costs $354.17 a month — $4,250 a year — while the principal never shrinks. The calculator prices this phase from the drawn balance and rate alone, because that's all that drives it.

Interest-only minimums are a cash-flow feature, not a discount. Every month you pay the minimum, the full balance survives into the repayment phase, where the payment math changes sharply.

The repayment-phase payment jump

When the draw period ends, the balance converts to a fully amortizing loan over the repayment term — commonly 10 to 20 years. That same $50,000 at 8.5% repaid over 15 years costs $492.37 a month, a $138.20 jump over the interest-only payment, and $38,626.56 of total interest. Compress the term to 10 years and the payment climbs to $619.93 while total interest falls to $24,391.41.

The jump is the number that catches borrowers out, which is why the calculator reports it explicitly. If the repayment-phase payment wouldn't fit your budget today, the line is a liquidity tool you should draw sparingly — not a long-term loan.

What the calculator deliberately ignores

HELOC rates float with the prime rate, so the real payment will move with the market; the calculator holds your entered rate constant and labels the output an estimate for exactly that reason. It also ignores annual fees, rate floors, promotional teaser rates, and minimum draw requirements, which vary by lender. Use it to size the decision, then read the specific offer's terms.

By variant

• Interest-Only Payment
• Repayment Phase

Questions

How much HELOC can I get on my home?

Multiply your home value by the lender's CLTV cap and subtract your mortgage balance. A $400,000 home with $250,000 owed supports a $90,000 line at 85% CLTV. Credit and income can reduce what's actually approved.

What is the monthly payment on a $50,000 HELOC?

During the draw period at 8.5%, interest-only is $354.17 a month. Once it amortizes over a 15-year repayment period the payment becomes $492.37 a month.

What does CLTV mean?

Combined loan-to-value: every loan secured by the home — first mortgage plus the HELOC line — divided by the home's value. Lenders usually cap CLTV between 80% and 90% for a HELOC.

Why does the payment jump after the draw period?

Because the minimum switches from interest-only to fully amortizing: you start repaying principal on a fixed schedule. On $50,000 at 8.5% the jump is $138.20 a month against a 15-year repayment term.

Is this a loan offer or financial advice?

No. It's arithmetic on the numbers you enter with the rate held constant. HELOC rates are variable and real offers depend on credit, income, and an appraisal.