Unmarried Couple Buying a House Together: Titling, Mortgage, and How to Protect Yourself

Start here: what marriage gives that you don't get

When a married couple buys a home, the law fills in a long list of defaults for them automatically. If one spouse dies, the other usually inherits without a will. In many states the home can be held in a way that shields it from one spouse's creditors. Federal tax law hands them a joint return, a doubled home-sale exclusion, and unlimited tax-free transfers between them. You get none of that by default. Every one of those protections has to be built on purpose, in writing, before something goes wrong.

That is not a reason to wait until you are married. On a large mortgage, buying while unmarried can actually be more tax-favorable, which we get to below. The point is simpler: a married couple can be a little sloppy and the law catches them. You cannot. This guide walks the four documents that do the catching, the title decision that drives all of them, and the 2026 tax facts the bank and brokerage pages still have wrong.

How to take title (the decision that drives everything)

The deed says how you co-own the property, and that choice controls what happens when one of you dies and how flexible you can be about unequal contributions. There are two forms that realistically apply to an unmarried couple, plus one that is closed to you.

• Tenancy in common (TIC). Each owner holds a defined share (which can be unequal, like 70/30). When you die, your share passes through your will or your state's intestacy law, not automatically to the other owner. Each owner's share is exposed to that owner's own creditors, and any co-owner can sell or mortgage their share. This is the right default for most unmarried buyers because it lets you match ownership to what each person actually puts in.
• Joint tenancy with right of survivorship (JTWROS). When one owner dies, their share passes automatically to the surviving owner outside of probate. Sounds ideal, but it is a trap if misused: shares are generally equal, the survivorship overrides whatever your will says, any owner can sever it at any time by deeding away their interest, and the home is exposed to each owner's creditors. Use it only when you genuinely want your partner to inherit your whole share and you contributed roughly equally.
• Tenancy by the entirety (TBE). This is the strong one: in the states that offer it, a creditor with a judgment against only one spouse generally cannot force a sale of the home. It is reserved for married couples. As an unmarried couple, you cannot use it. Competitors leave this out by silence; the creditor shield people most want is the one you are not allowed to have.

The free titling decision table

CoBuy puts its version of this behind a paid annual subscription. Here is a free one. Find the row that matches what each of you is contributing and whether you want your partner to inherit your share, then read across. Whatever the table says, pair it with a cohabitation agreement (next section). State title rules vary, so confirm the form with a local real-estate attorney before you sign.

Deed vs. mortgage: the two-document trap

The deed and the mortgage are different documents that answer different questions. The deed says who owns the home. The mortgage (technically the promissory note) says who owes the debt. It is completely legal to have one person on the loan and both on the deed, or the reverse. Each mismatch is a trap:

• On the loan but not the deed. You are 100% liable for the debt and own nothing. If the relationship ends, you have been paying a mortgage on a house that is legally your partner's.
• On the deed but not the loan. You own a share but have no contractual duty to pay. You are relying on the borrower to keep paying, because a default and foreclosure take down the home you co-own even though your name is not on the note.
• Both on the loan. The lender holds you jointly and severally liable. That means it can pursue either of you for the entire balance, not half each. Every late payment hits both credit reports. After a breakup, a quitclaim deed moves the title but does NOT remove anyone from the loan. The only clean way to release a co-borrower is to refinance the mortgage into the remaining owner's name alone, which requires that person to qualify solo.

The inheritance trap nobody warns you about

This is the single biggest risk the bank and brokerage pages gloss over. An unmarried partner is not a legal heir. If you die without a will while holding your share as a tenant in common, that share passes under your state's intestacy statute, which sends it to your closest blood relatives: children, parents, siblings. Your partner can be left co-owning the home with your family, or with nothing, depending on the state and who else survives you. No amount of "we always meant for it to go to each other" overrides the statute.

Three fixes, and you generally want more than one:

1. A will that explicitly leaves your share to your partner. This is the floor. Without it, intestacy decides for you.
2. A transfer-on-death (beneficiary) deed, where your state allows one. It names your partner to receive your share at death and keeps it out of probate, while staying fully revocable if the relationship changes. Roughly half the states offer TOD deeds, so confirm yours does.
3. JTWROS title or a living trust if you want the home to bypass probate entirely. Survivorship is automatic but inflexible; a trust costs more to set up but gives you precise control.

The cohabitation agreement and the buyout formula

If you do one protective thing beyond the deed, make it this. A cohabitation or co-ownership agreement is a written contract between the two of you that the deed cannot capture. Have a lawyer draft or review it, because enforceability varies by state: agreements framed around the romantic relationship itself (rather than the property and money) can be void in some states, and common-law-marriage states treat these differently. Keep the agreement about the house. It should cover:

• Ownership percentages and how they are calculated (tie this to your contribution ledger).
• A who-pays-what ledger: mortgage, taxes, insurance, repairs, and major improvements, and how a partner who overpays is credited.
• A buyout formula for a breakup: how the home is appraised (for example, an independent licensed appraiser, or the average of two), how appreciation is divided, who gets the first right to buy the other out, and a deadline to refinance the loan into the buyer's name.
• What happens if you cannot agree: mediation or arbitration before anyone files in court.
• A partition waiver (covered next), so neither of you can force a court sale on a whim.
• Death: what happens to each share, coordinated with your wills and any beneficiary deed so the documents do not contradict each other.

Partition: how a co-owner can force a sale

Here is the exit nobody mentions until it happens. If two co-owners cannot agree on what to do with a property, either one can file a partition action and ask a court to force a sale. For a single home that cannot be physically divided, courts almost always order a partition by sale (the house is sold and the proceeds split) rather than a partition in kind (physically dividing the land). The right is statutory: in California, for example, Code of Civil Procedure section 872.210 lets any co-owner of real property bring a partition, and pointedly excludes married couples' community property, which is exactly why partition is an unmarried co-owner's default exit.

Partition is slow, expensive, and adversarial, and it hands the timing and price to a court instead of to you. Many states have adopted a version of the Uniform Partition of Real Property Act (or its predecessor, the Uniform Partition of Heirs Property Act), which adds buyout and fair-market-value protections for tenants in common, but it does not make the process pleasant. The real defense is contractual: a partition waiver in your cohabitation agreement, in which you both agree not to seek partition (or to follow your buyout formula first). Without that waiver, your buyout formula is only as strong as your ex's willingness to honor it.

Taxes, done right and current to 2026

This is where being unmarried actually changes the math, and where every dated competitor page is now wrong. Four things to get right:

1. The mortgage-interest limit can work in your favor on a big loan. The deduction is capped at the interest on $750,000 of acquisition debt. A married couple filing jointly shares one $750,000 cap. But under Voss v. Commissioner (9th Cir. 2015), which the IRS officially agreed to follow in Action on Decision 2016-02, the debt limit applies per taxpayer for unmarried co-owners. Two unmarried co-owners can each have their own limit. The catch, and it matters: each of you only gets your own limit if you are both legally liable on the note and each actually pays the interest you deduct. This only changes anything when the mortgage is large (well above $750,000), you are both on the loan, and you both itemize. For a typical sub-$750,000 mortgage, or if you take the standard deduction, there is no difference at all. But on a high-balance loan, two unmarried buyers can be better off than a married couple, the opposite of what most people assume.

2. Splitting the interest deduction. When two non-spouses are both liable for and pay interest on the same mortgage, IRS Publication 936 tells you to each deduct only the share you actually paid, and to attach a statement to the return showing how the interest was split (since only one of you receives the Form 1098). Allocate by who really paid, and keep the ledger to prove it.

3. The capital-gains exclusion is parity at best, not a married-style bonus. Under Internal Revenue Code section 121, each owner can exclude up to $250,000 of gain when you sell, but only if that owner individually meets both the ownership test and the use test (owned and lived in the home as a principal residence for at least 2 of the last 5 years). Two qualifying co-owners can shelter up to $250,000 each. The married $500,000 figure requires a joint return. The trap: a partner who is not on title, or who fails the tests, gets $0. So the real tax edge for unmarried buyers is the mortgage-interest treatment above, not capital gains.

4. Watch the gift tax on mismatched contributions. A gift happens when what you pay does not match the title you take, not from unequal contribution by itself. If you pay 70% of the costs but take only 50% of the title, you have made a gift of that extra 20% to your partner. The 2026 annual exclusion is $19,000 per recipient; give more than that in a year and you file Form 709 (you almost certainly owe no tax, because it just draws against the $15 million lifetime exemption, but the form is required). The clean fix is to match title to your contribution ledger so there is no gift to report. And remember: you each file as Single (or Head of Household if you qualify). There is no joint return for you.

Qualifying for the loan, and incapacity planning

On a joint application, lenders generally qualify you on the lower of your two median credit scores, and they count both incomes and both debts toward your debt-to-income ratio. If one of you has a weak score or heavy debt, applying with one borrower alone can mean a better rate, with the trade-off that only that person is on the loan (revisit the deed-vs-loan traps above before doing that). Your marital status cannot legally be the reason for a denial: the Equal Credit Opportunity Act (15 U.S.C. 1691) prohibits credit discrimination based on marital status. Note that this protection lives in ECOA, not the Fair Housing Act, which does not list marital status among its protected classes.

Finally, plan for incapacity, because an unmarried partner has no automatic right to make your medical or financial decisions the way a spouse does. Sign a durable power of attorney (so your partner can handle finances, including the mortgage, if you are incapacitated) and a healthcare proxy or advance directive (so they can make or hear medical decisions). Without these, your partner can be locked out of the hospital room and the bank, and a court may hand both roles to a blood relative instead. Title rules, TOD-deed availability, partition statutes, and community-property regimes all vary by state, so use this as a framework and confirm the specifics with a local real-estate attorney and a tax professional.