Subject-To Deal Calculator
Analyze "Sub-To" real estate deals. Calculate your Total Entry Fee (Cash to Close) and monthly Cash Flow by taking over the seller's existing mortgage payments.
How to Use the Subject-To Deal Calculator
Evaluating a sub-to deal has three core questions: how much cash does it take to get in, how much cash flow does it produce each month, and how efficiently is that capital working? Follow these five steps and the calculator answers all three in real time.
Enter the Deal Structure
Start by entering the agreed purchase price and the seller’s existing loan balance. The difference between these two numbers is the seller’s equity — the cash they expect to receive at closing. Enter the existing interest rate for reference, and the current PITI payment (principal, interest, taxes, and insurance) exactly as it appears on the seller’s mortgage statement. The PITI is the single most important number in any sub-to deal because it directly determines your monthly cost.
Add Your Entry Costs
The total entry fee (cash to close) has five components. Enter any arrears or back payments needed to bring the loan current. Add your closing and agent fees — title, escrow, attorney, and transaction costs. Include your renovation budget if the property needs work before renting. If a wholesaler sourced the deal, add their assignment fee. The calculator sums all five and shows your total cash-out-of-pocket alongside what each component represents as a percentage of the total.
Set Your Projected Rental Income
Enter the gross monthly rent you expect to collect from the property. This should reflect realistic local market rents — not aspirational numbers. Pull comparable active listings and recent rental comps from Zillow, Rentometer, or a local property manager. The calculator will subtract the existing PITI payment from your projected rent to produce the net monthly cash flow. If you plan to house-hack, enter your target rent minus your personal occupancy cost to keep the numbers accurate.
Calculate and Analyze the Deal
Click “Calculate Deal” to instantly see your full deal analysis: total entry fee, net monthly cash flow, annual cash flow, cash-on-cash return, loan-to-value ratio, and instant equity position. Six summary snapshot cards give you every key metric at once. The breakdown bars show visually how your entry costs are distributed and how the monthly spread compares to the PITI payment. A positive cash flow card turns green; negative turns red — letting you screen deals in seconds.
Download the PDF Deal Report
Click “Download PDF” to generate a professional two-page deal analysis you can share with a partner, attorney, private lender, or the seller themselves. Page 1 covers the complete deal structure — entry fee breakdown, monthly cash flow, snapshot metrics, and visual charts. Page 2 is a full deal summary table with every input and output labeled, plus a formatted legal disclaimer. The PDF is clean, branded, and structured like a professional deal memo — not a screenshot.
What This Calculator Shows You
A sub-to deal has more moving parts than a simple rental acquisition. This calculator surfaces every number both buyers and sellers need before any agreement is put in writing.
Total Entry Fee (Cash to Close)
The hero metric: every dollar the buyer must bring to closing across all five cost components — seller equity, arrears, closing fees, renovation, and assignment. Unlike a traditional purchase with a large down payment and new mortgage, sub-to entry fees are often a fraction of the property’s value, which is what makes the strategy attractive. The entry fee breakdown bar shows what proportion each component represents so you can identify where negotiation leverage exists.
Net Monthly Cash Flow
The monthly profit: projected rent minus the existing PITI payment. This is the gross spread before vacancy, maintenance, and property management — which experienced investors typically budget at an additional 30–40% of gross rent. The cash flow figure is color-coded: green for positive deals, red for negative. A negative cash flow isn’t automatically a deal-killer — some investors accept break-even or slight negative cash flow in exchange for high equity or appreciation upside — but the number must be understood clearly before closing.
Cash-on-Cash Return (CoC)
The annual net cash flow divided by the total entry fee — expressed as a percentage. This is the most important capital efficiency metric in sub-to investing. Because entry fees are typically far lower than a traditional down payment, CoC returns on well-structured sub-to deals can dramatically outperform conventionally financed acquisitions. A 50% CoC return means your invested capital doubles as cash income in two years. Use this figure to compare deals and benchmark against your own investment targets.
Loan-to-Value & Instant Equity
The LTV percentage shows how much of the purchase price is covered by the existing loan — a critical number for both parties. A lower LTV means the buyer has more equity cushion; a higher LTV means more leverage. Instant equity is the difference between the purchase price and the existing loan balance — it represents the buyer’s immediate equity position at closing, before any appreciation. Sellers should note that high LTV deals offer less buffer if the buyer defaults and the property must be re-sold.
Annual Cash Flow
Monthly net cash flow multiplied by 12 — the annual income the deal generates before vacancy and operating expenses. This figure is useful for comparing deals of different sizes and evaluating the opportunity cost of capital. It also anchors the conversation with private lenders or partners who want to understand the deal’s income profile. For sellers who are evaluating a sub-to sale versus holding as a rental themselves, the annual cash flow shows what the buyer is capturing that they’re giving up.
PDF Deal Report (2 Pages)
A professionally formatted, downloadable deal analysis — the same document you’d share with a real estate attorney before structuring the transaction, a private lender evaluating the deal as collateral, or a co-investor reviewing the numbers. Page 1 covers the deal structure with entry fee breakdown, cash flow analysis, visual charts, and snapshot metrics. Page 2 is a complete deal summary table with every input and output labeled. No spreadsheets, no screenshots — a clean, branded report ready to share.
Key Benchmarks for Subject-To Real Estate Deals
The Due-On-Sale Clause: The Primary Risk in Every Sub-To Deal
Lender Can Accelerate the Full Loan Balance Upon Discovery of Title Transfer
Virtually all conventional mortgages originated after 1982 contain a due-on-sale clause that allows the lender to demand immediate repayment of the full outstanding balance when the property is sold or title is transferred — even if payments remain current. In a subject-to transaction, title transfers to the buyer while the original mortgage stays in the seller’s name. This can technically trigger the clause. While many lenders do not proactively monitor title transfers, the risk is real and the consequences severe. If the lender discovers the transfer and exercises their rights, the entire loan balance becomes immediately payable. Always engage a licensed real estate attorney in your state before executing any subject-to transaction. Some investors use land trusts or title-holding entities to reduce the visibility of the transfer, but there is no zero-risk structure when conventional loans are involved.
Common Subject-To Deal Structures
“Subject-to” describes a category of acquisition, not a single contract type. The entry fee and cash flow math is identical across all structures — which is why this calculator applies to all of them.
The buyer takes title via a warranty deed or grant deed, and the seller’s existing mortgage stays in place in the seller’s name. The buyer makes monthly payments directly to the loan servicer (or through a third-party servicing company) going forward. No new financing is originated. The seller receives their equity as cash at closing and walks away. This is the simplest and most common sub-to structure — the buyer controls the property and makes the existing payments while building equity through principal paydown, cash flow, and appreciation.
When the seller has significant equity above the existing loan balance, the buyer may not have enough cash to pay that equity in full at closing. In a hybrid structure, the buyer takes title subject-to the existing mortgage and simultaneously signs a separate promissory note to the seller for all or part of the equity. The seller holds a second lien position. The buyer makes two payments: one to the existing lender and one to the seller on the carryback note. This allows buyers to acquire properties with minimal upfront capital while giving sellers an income stream on their equity.
A land trust (also called an Illinois land trust or title-holding trust) is a legal entity that holds title to real property. In a sub-to land trust structure, the seller conveys title into the land trust at closing. The buyer becomes the beneficiary of the trust, gaining control of the property without appearing on the public deed as the new owner. Because the trustee — not the buyer — holds title, the transaction may be less visible to the existing lender. This structure is used specifically to reduce due-on-sale risk. It does not eliminate it — legal advice is essential — but it can reduce the probability of lender discovery.
A sub-to lease option pairs the subject-to acquisition with an outbound lease-option agreement to a tenant-buyer. The investor takes the property subject-to, then simultaneously leases it to a tenant who has the option to purchase at a set price within a defined period. The investor collects rent from the tenant (ideally above the PITI payment for positive cash flow), receives a non-refundable option fee upfront, and locks in a future sale price. When the tenant-buyer exercises their option, the investor uses the proceeds to pay off the underlying loan and capture the spread — without ever refinancing.
A wholesaler identifies a motivated seller willing to sell subject-to, negotiates the deal, and then assigns their rights under the sub-to purchase contract to a cash buyer or end investor for an assignment fee. The wholesaler never takes title — they simply control the contract and sell that equitable interest. The end buyer steps into the contract and closes with the seller directly. Assignment fees for sub-to deals typically range from $5,000 to $25,000+ depending on the deal’s equity and cash flow profile. This calculator’s “assignment fee” input field is specifically designed for investors evaluating wholesaled sub-to deals.
Subject-To vs. Wrap Mortgage vs. Seller Financing
These three creative financing strategies are frequently confused. Each has distinct mechanics, risk profiles, and use cases. Understanding the differences determines which structure fits a given deal.
| Feature | Subject-To | Wrap-Around Mortgage | Seller Financing |
|---|---|---|---|
| Who holds the existing mortgage? | Seller (stays in seller’s name) | Seller (stays in place) | N/A — no existing loan required |
| Title transfer to buyer? | Yes — at closing | Yes — at closing | Yes — at closing |
| New financing originated? | No — existing loan taken over | Partial — new wrap note issued | Yes — seller issues new note |
| Monthly payment flow | Buyer → Existing lender | Buyer → Seller → Original lender | Buyer → Seller (no original lender) |
| Seller’s monthly income? | None — seller exits at closing | Yes — rate spread each month | Yes — full note payment |
| Due-on-sale risk | High — title transfers, loan stays | Yes — title transfers | None — no underlying loan |
| Seller’s ongoing credit risk? | Yes — loan stays in seller’s name | Lower — seller holds the note | None — seller is the lender |
| Best when seller has… | Low-rate mortgage + motivated to exit | Low-rate mortgage + wants monthly income | Free-and-clear property |
| Buyer bank qualification required? | None | None | None |
| Attorney required? | Yes — always | Yes — always | Yes — strongly recommended |
| What this calculator models | ✓ Designed for this | Use Wrap-Around Mortgage Calculator | Use Seller Financing Calculator |
Which tool to use: If the seller wants to earn a monthly rate spread on their existing low-rate mortgage, use the Wrap-Around Mortgage Calculator. If the seller owns the property free and clear and is creating a new loan from scratch, use the Seller Financing Calculator. This Subject-To Calculator is purpose-built for deals where the buyer takes title and the existing mortgage stays in place.
How Different Parties Use This Calculator
The numbers you care about depend entirely on which side of the deal you’re on. Here’s how each party should approach the analysis.
Motivated Sellers
Solving a problem, not maximizing priceYou’re behind on payments, going through a divorce, relocating urgently, or facing a property you can no longer manage. A sub-to buyer can close in weeks, bring your loan current, and take the property off your hands without you having to list, show, or wait. The trade-off: your name stays on the mortgage until the buyer refinances or sells.
- Use this calculator to understand exactly what the buyer will net from your property
- Confirm the entry fee covers any arrears so your loan is brought current immediately
- Insist on a third-party servicer so you receive monthly proof the loan is being paid
- Ask your attorney about adding a performance deed of trust as additional protection
- Monitor your credit report monthly — the loan is still legally yours until it’s paid off
Real Estate Investors
Scaling without bank approvalYou’re building a rental portfolio but hitting lending walls — Fannie Mae’s 10-loan limit, DTI restrictions, or self-employment income challenges. Sub-to lets you acquire properties with low upfront capital, no bank qualifying, and below-market financing already locked in. Your edge is speed and deal structure creativity.
- Run CoC return first — target 30%+ on your capital for sub-to deals to make sense
- Model multiple renovation scenarios using the renovation budget input field
- Low entry fee + high cash flow = deals worth pursuing; high entry fee negates the advantage
- Use the PDF as a deal memo when presenting to private lenders or JV partners
- The LTV metric tells you how much equity buffer you have if the market softens
Wholesalers & Deal Scouts
Finding and packaging sub-to dealsYou source deals from motivated sellers and assign the contract to end investors for an assignment fee. Your value is in identifying properties where the existing mortgage creates a favorable entry structure — then packaging the numbers clearly enough that a buyer closes quickly without re-trading the price.
- Enter your assignment fee in the calculator — it’s part of the buyer’s true entry cost
- Target PITI payments well below market rent — that’s where the cash flow story is strongest
- Download the PDF and attach it to your deal presentation to buyers — it builds credibility
- CoC return is your headline number; anything above 40% attracts sophisticated buyers fast
- Instant equity shown in the snapshot cards helps buyers see beyond cash flow alone
7 Things to Know Before Buying Subject-To
Sub-to is one of the most powerful acquisition strategies in creative real estate — and one that rewards preparation. These considerations apply to every deal regardless of property type, seller situation, or market.
Verify the Existing Loan Type Before Making an Offer
Not all mortgages carry the same due-on-sale risk. Conventional Fannie Mae and Freddie Mac loans have strictly enforced due-on-sale clauses and active transfer monitoring. FHA loans are technically assumable — creating a different, cleaner legal path. VA loans can be assumed by eligible buyers with VA approval. Portfolio loans held by small community banks and credit unions often have flexible or non-enforced due-on-sale language. Request a copy of the seller’s original note and deed of trust before structuring anything. The loan type determines the strategy, the risk level, and the legal approach your attorney will recommend.
Always Use a Licensed Real Estate Attorney in Your State
Subject-to law varies by state. The deed language, seller disclosures, warranty provisions, default remedies, and due-on-sale risk mitigation strategies are all state-specific. An attorney who practices in the county where the property is located — not just any real estate attorney — must draft the purchase agreement, warranty deed or grant deed, power of attorney (if used), and any performance deed of trust or seller protection instrument. The legal cost ($1,500–$3,500) is a fraction of the risk exposure for both parties if the transaction is improperly documented.
Use a Third-Party Loan Servicing Company for Both Parties’ Protection
The seller’s primary risk is the buyer defaulting on the underlying mortgage — damaging the seller’s credit and potentially leading to foreclosure on a property they no longer own. A licensed loan servicing company collects the buyer’s payment each month, pays the underlying lender directly (with proof), and sends both parties a confirmation and payment ledger. This protects the seller from buyer default, gives the buyer documentary proof of payment history, provides clean tax records for both parties, and demonstrates good faith if the transaction is ever scrutinized. Cost: $25–$75/month. It should be non-negotiable in every sub-to deal.
Get the Full PITI — Not Just the Principal and Interest
The biggest cash flow modeling error in sub-to analysis is entering only the principal and interest (P&I) payment while ignoring taxes and insurance — also known as the T&I portion of PITI. If taxes and insurance are escrowed into the monthly payment (which they are in most conventional loans), the full PITI is what you actually owe each month. Ask the seller for their most recent mortgage statement and use the “Total Monthly Payment” line — not the “Principal and Interest” line. Entering the wrong figure by even $200–$400 per month can make a mediocre deal look like a great one in your analysis.
Model a Realistic Exit Before You Close
Every sub-to deal needs a defined exit strategy from day one. The most common exits are: (1) the buyer refinances into a new conventional loan once they’ve built equity and the property is stabilized — typically 12–24 months; (2) the property is sold outright, proceeds pay off the underlying loan, and the buyer pockets the appreciation; (3) a tenant-buyer exercises a lease option; or (4) the sub-to note itself is sold to a note investor. Understand which exit is most likely for your deal, then stress-test it: what if rates are still high in two years? What if the property needs a refinance and the ARV doesn’t support it? Plan your exit before the ink is dry on the deed.
Protect the Seller with a Performance Deed of Trust
A performance deed of trust (also called a performance mortgage) is a security instrument recorded against the property in the seller’s favor. It gives the seller a lien position — typically second behind the existing mortgage — that can be enforced if the buyer fails to perform under the sub-to agreement. If the buyer stops making the underlying mortgage payment, the seller can foreclose on their performance deed of trust to take back the property before the original lender’s foreclosure process completes. Not every state allows or recognizes this instrument the same way, which is one more reason state-specific legal counsel is essential. Including this protection significantly increases seller confidence and reduces negotiation friction.
Budget Beyond the Entry Fee — Operating Costs Are Real
The entry fee in this calculator represents your cash to close — not your total capital at risk. Operating a rental property sub-to requires budgeting for vacancy (typically 5–8% of gross rent annually), maintenance and repairs (budget 5–10% of gross rent), capital expenditure reserves for roof, HVAC, and appliances (5–10%), and property management if you’re not self-managing (8–12% of collected rent). A deal that shows $600/month in gross cash flow may net $200–$300 after these real costs. Model your cash flow with an expense ratio of 40–50% of gross rent and see if the deal still works. This calculator shows the gross spread — the operating reality is where experienced investors separate profitable deals from costly ones.
Subject-To Deal Calculator FAQ
Plain-language answers to the questions buyers, sellers, and investors ask most about subject-to real estate transactions.
Important disclaimer: All calculations provided by this tool are for educational and estimation purposes only and do not constitute financial, legal, or real estate advice. Subject-to transactions are complex real estate structures that may trigger due-on-sale clauses in the existing mortgage, violate the terms of existing loan agreements, or be subject to state-specific regulations and disclosure requirements. Results are based entirely on the inputs you provide and standard arithmetic. This calculator does not model due-on-sale enforcement probability, lender monitoring practices, vacancy rates, operating expenses, maintenance costs, tax consequences, legal structuring costs, or state-specific legal requirements. The existing PITI payment must be verified against the seller’s actual mortgage statement — an incorrect figure will produce inaccurate results. Any subject-to real estate transaction must be reviewed and documented by a licensed real estate attorney in the state where the property is located before any agreement is signed or title is transferred. HomeExpertly is not a lender, broker, financial advisor, or attorney.