Subject To Calculator: Know If The Takeover Pays Before You Sign.
In a subject-to deal you buy the property subject to its existing financing: the loan stays in place and you take over the monthly payments. This free calculator tells you in under 60 seconds whether that takeover cash flows, including the catch-up costs most first analyses miss: back payments, liens, closing costs, and reserves.
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How The Subject To Calculator Works
The payment already exists. The question is whether taking it over pays you.
Enter the takeover numbers
Purchase price, the existing monthly payment (PITI), and market rent. The monthly spread and deal score appear instantly.
Add the catch-up costs
Back payments and liens that transfer with the property, closing costs, repairs, and first-year insurance. This is where subto deals are won or lost.
Check reserves and exits
A 3-month payment reserve is calculated automatically. Then compare a standard rental exit against a rent-to-own exit on the same takeover.
📊 The takeover
- Existing payment & PITI
- Spread vs. market rent
- Back payments & liens
- 3-month reserve (automatic)
- Deal score (0-100)
🚀 The exit
- Rent-to-own option deposit
- Move-in cash collected
- Cash still in deal after deposit
- Boosted cash-on-cash return
- Side-by-side comparison
| Rental Exit | + Rent-to-Own Exit | |
|---|---|---|
| Monthly Cash Flow | $387 | $387 |
| Upfront Cash | $0 | +$18,000 |
| Cash-on-Cash Return | 8% | 37% |
| Deal Score | 74/100 | 91/100 |
The Numbers Subto Investors Miss
The spread looks great until the catch-up costs land. The calculator makes them visible up front.
Back payments & liens
Missed payments, back taxes, and HOA arrears transfer with the property. Enter them once and every return number updates to the real cost of entry.
The 3-month reserve
The calculator automatically sets aside three months of the payment you are taking over. A takeover without reserves is a takeover that fails on the first vacancy.
Stress-tested spread
Add a vacancy rate and a maintenance reserve and watch the spread recalculate. A spread that survives 8 percent vacancy is a spread you can trust.
Frequently Asked Questions
What is a subject-to deal?
A subject-to deal means buying a property subject to its existing financing. The seller's loan stays in place and you take over making the monthly payments. Your cost of entry is whatever it takes to catch up the loan, close, and reserve, which on some deals is very little.
How do I analyze a subject-to deal?
Start with three numbers: the purchase price, the existing monthly payment you would take over (PITI: principal, interest, taxes, insurance), and the market rent. If rent minus payment leaves a healthy monthly spread, the deal cash flows. Then add your cash to close, back payments, closing costs, and repairs to see the true cash-on-cash return.
What are back payments and liens in the calculator?
Existing debt that transfers with the property: missed mortgage payments, back taxes, HOA arrears. The calculator adds them to your cost of entry so the cash-on-cash return reflects what the deal really costs to take over.
How much cash does a subject-to deal take?
Whatever it takes to catch up the existing loan, cover closing costs and repairs, and hold a reserve. The calculator totals all of it, including an automatic 3-month payment reserve, and shows the full number before you commit.
What monthly spread is good on a subto takeover?
A monthly spread of $300 or more between market rent and the payment you take over scores as strong in this calculator, $100 to $300 is tight, and below $100 the deal needs renegotiation. Stress test the spread with vacancy and maintenance before trusting it.
Can I add a rent-to-own exit to a subject-to deal?
Yes. Enter a tenant-buyer's option deposit and the calculator shows the same takeover side by side: standard rental vs rent-to-own, including move-in cash collected and the boosted cash-on-cash return.
Is the subject to calculator free?
Yes. Enter your name, email, and phone number and access is sent to you instantly. There is no paid version.
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