Investment Property HELOC Calculator Draw and Repayment Phases

The Quick Read: An investment property HELOC has two payment phases, and a calculator has to model both. During the draw, the payment is usually interest on the balance only. In repayment, the line closes to new draws and the balance amortizes, so the payment steps up.

• On the investment lines Lendmire’s wholesale network places, the draw runs 5 years, followed by a 25-year fully amortizing repayment, subject to lender guidelines.
• Pricing floats through both phases and never converts to fixed.
• The ceiling on an investment line is 70% CLTV, with a 700 minimum credit profile and a $500,000 maximum line.
• A HELOC is judged on the borrower, not on rent. A rental that clears 1.00x on its first mortgage can still run thin once the HELOC payment is stacked on top.
• Any calculator is an illustrative estimate, not a quote or a payment.

What Does a HELOC Calculator Actually Model?

A HELOC calculator models two different payments off one balance. The draw-phase payment is balance times the annual rate divided by 12. The repayment payment uses the standard amortization formula. The calculator’s inputs are the balance, the rate, and the length of each phase.

The amortization formula is P × r(1+r)^n ÷ (1+r)^n − 1. Here r is the monthly rate and n is the number of months left in repayment. Three variables drive the step-up: the balance when the draw ends, the rate at that time, and the repayment length. A shorter repayment term means a larger payment.

This article uses no payment dollars on purpose. The logic matters more than any single output, and the site’s calculator is an illustrative estimate only.

How Do the Draw and Repayment Phases Work?

The federal consumer-finance regulator describes a HELOC as an open-end line of credit with a borrowing period and a repayment period. Once the draw ends, borrowing stops. Payments are often significantly higher in repayment, and some plans require the full balance at once as a balloon.

Here is the sequence on a typical investment line:

1. Sizing. The lender takes property value, applies the CLTV ceiling, and subtracts existing liens. What is left is the potential line.

2. Closing. On the network’s investment lines, at least 75% of the line is drawn at closing. That matters, because it means the interest-only payment starts near the full line, not near zero.

3. Draw phase. The investor can borrow, repay, and borrow again up to the limit. The minimum subsequent draw is $1,000 in most states and $4,000 in Texas, where that figure applies.

4. Transition. The line closes to new draws. Unused availability disappears, and the balance is re-amortized over the repayment term.

5. Repayment phase. Principal and interest are both due, and floating pricing keeps moving the payment.

Why Does the Payment Jump?

The payment jumps because principal enters the payment while the term shrinks. An interest-only payment leaves the balance untouched, so the full amount is still owed on day one of repayment. Spreading that balance over the repayment term adds principal to every payment.

The federal consumer-finance regulator’s HELOC brochure notes that some plans require principal during the draw, while others allow interest-only payments. It also warns that with a variable rate, payments can change even if you draw no more money.

The size of the jump at the end of the draw period depends on rate and term, and it is often substantial. A longer repayment term softens it. A shorter one sharpens it.

What a Calculator Should Run on a Rental

A rental calculator needs three scenarios, not one. Model the payment at the full drawn balance, the payment after the draw ends, and the payment if the index moves against the borrower. Then lay rent against each one.

Here is the part most calculators skip. Rent rarely steps up when the payment does. Picture an investor whose rental covers its first mortgage and the HELOC‘s interest-only payment with room to spare, at roughly 1.3x on a combined basis. When repayment starts, the HELOC payment rises while rent stays flat. Coverage can slide toward 1.0x or below with no change in the property at all.

This is why a DSCR figure on the first mortgage does not describe the whole position. DSCR compares rent to PITIA only. It ignores a second lien on other collateral, and it ignores repairs, vacancy, management, and capex. Clearing 1.00x is not the same as positive cash flow.

For the full picture of how coverage works on the first loan, see Lendmire’s complete DSCR loans guide.

How Does Underwriting Treat an Investment HELOC?

Underwriting treats it as a borrower loan. The review looks at credit, equity, existing liens, and DTI, not at rent. That is the sharpest difference from a DSCR loan.

On the network’s investment lines, the parameters look like this, subject to lender guidelines and full file review:

• Leverage: 70% CLTV on an investment property, for both the 720+ and 700+ tiers. Credit above 700 buys eligibility, not extra leverage.
• Credit: 700 minimum, with no tier beneath it.
• Line size: capped at $500,000 on an investment property.
• DTI: 50% maximum, qualified on the interest-only payment calculated on the maximum draw, not on what the investor expects to draw.
• Valuation: because the line caps at $500,000, it usually runs an automated valuation with no traditional appraisal.

NerdWallet reports that rental lines come with a smaller lender pool, lower limits, and stricter reserve and appraisal expectations than primary-home lines. The network figure for an investment property is 70% CLTV.

The DTI point is the one that surprises people. Qualifying on the full line’s interest-only payment uses up DTI room, and that can affect the next purchase. DSCR lender review itself qualifies primarily on property-level rental income covering the payment, subject to lender guidelines.

Where the General Rule Breaks

The 5-year and 25-year pattern is a common shape, not a law. The edge cases are where files go wrong.

Balloon plans. Some lines in the wider market require the full balance when the draw ends. The network’s investment lines amortize, but any line should be checked against its own agreement.

Title. Individual or revocable trust title is required. LLCs, corporations, partnerships, and irrevocable, blind, or land trusts cannot hold title. An investor whose rental already sits in an LLC needs a vesting change, or a DSCR cash-out refinance instead. Lendmire’s piece on whether a HELOC or a cash-out refinance fits a small draw covers that tradeoff.

Floating pricing. Pricing floats across both phases and never converts to fixed. Some primary-home lines elsewhere offer fixed conversions. Do not assume one here.

State differences. Tennessee shortens the repayment structure. Texas carries a higher minimum subsequent draw. A property listed for sale, or listed within the past 60 days, is ineligible in several states.

Property type. Single-family, 2-4 units, PUDs, townhomes, and condominiums, including non-warrantable ones, are eligible. Manufactured homes, co-ops, condotels, log homes, commercial, mixed-use, and agricultural-zoned properties are not offered.

Freezes and reductions. The CFPB brochure notes plans can allow a freeze or reduction of the line. A calculator that assumes cash will be there later is making an assumption the agreement may not support.

Availability. HELOC placement runs in 16 full-service states, narrower than Lendmire’s 41-market DSCR footprint, which includes Washington, D.C.

Key Terms Defined

Draw period: the phase when the borrower can take money from the line and usually pays interest only.

Repayment period: the phase after the draw closes, when principal and interest are both due.

CLTV: combined loan-to-value, which adds every lien on the property and divides by its value.

Interest-only payment: a payment that covers interest and leaves the principal balance unchanged.

Balloon: a lump-sum balance due at the end of a phase instead of an amortizing schedule.

Amortization: paying a balance down over a set term through regular principal-and-interest payments.

Planning Before the Draw Ends

The calculator is only useful if the dates come from the agreement. Find the draw end date and the repayment length in the loan documents, then work backward.

1. Model the step-up with the balance you expect to carry, not the line limit.

2. Stress the index. Add a rate move on top of the repayment payment and check coverage against rent.

3. Check the stabilization clock. A rental still in lease-up when repayment starts is exposed.

4. Build reserves. The first mortgage and the HELOC both need to survive a vacancy.

5. Pick an exit. Pay down the balance, sell, or refinance. A DSCR cash-out refinance replaces the first mortgage and is judged on rent against payment, with leverage typically topping out around 75% on a standard rental, subject to lender guidelines.

On a portfolio, repayment dates can stagger or collide. A borrower is limited to three lines, and combined exposure caps vary by program. Lendmire’s piece Investment Property HELOC Draw Period for a Portfolio Investor covers that view.

Paying principal during the draw is the simplest lever. A lower balance entering repayment means a smaller re-amortized payment. Interest-only keeps the draw cheap, but it defers the cost.

Tax treatment can depend on how the funds are used and how the property is held; investors should keep clear records and speak with a qualified tax professional before relying on any deduction.

If you are considering a home equity line and want to see how the numbers work, Lendmire can help you compare HELOC options based on the property, the equity available, credit profile, combined leverage, and your goals. Reach the team at 828-256-2183.

About Lendmire

Lendmire is a mortgage brokerage (NMLS# 2371349) arranging home equity lines of credit — primary-residence, second-home and investment-property lines — through a wholesale lending network in its 16 full-service states. Eligibility is determined by the lender on each file. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. CFPB – What is a HELOC (Ask CFPB)

2. CFPB – HELOC brochure

3. NerdWallet – Can You Get a HELOC on an Investment Property?