US couples · Legal docs
Cohabitation Agreement Cost in 2026, and What It Actually Has to Include
A clear price breakdown for unmarried US couples, a copy-ready clause checklist, and the enforceability rules and hard limits most pages skip.
A cohabitation agreement runs about $0 to $50 for a DIY template, $200 to $750 for a flat-fee online service, and $500 to $2,500 for an attorney-drafted one, roughly double if each partner hires their own lawyer. The 10x spread tracks how many assets and how much risk you are dividing.
The short version
- Budget by complexity, not by a single number. Renters splitting furniture can use a $0 to $50 template. Couples with a house, a business, retirement accounts, or a big income gap should pay for two lawyers.
- Enforceability is earned, not assumed. Put it in writing, give full financial disclosure, sign voluntarily, and ideally have separate counsel. An agreement built on sex as the consideration is void.
- It cannot control child support or custody. A court decides those by the child's best interests and is not bound by your contract. Support is the child's right and parents cannot waive it.
- Your state matters. Most states enforce these agreements under Marvin v. Marvin, but a notable minority, including Illinois, refuse on public-policy grounds. Check your own state before you rely on it.
- It does not replace an estate plan. An unmarried partner inherits nothing automatically and gets no spousal tax breaks. Pair the agreement with a will, beneficiary designations, a power of attorney, and a healthcare proxy.
- Living together is not marriage. A cohabitation agreement is a contract, not a marital status, and only about eight states still recognize new common-law marriage.
On this page
What a cohabitation agreement costs in 2026
There is no single price, and any page that gives you one number is hiding the part that matters. The real answer is a range that depends on how you have it made and how much you are dividing. Here is the 2026 market, broken into the four ways people actually get one.
| How you get it | Typical 2026 cost | Enforceability | Best for |
|---|---|---|---|
| DIY template (PDF or Word) | $0 to $50 | Weakest. No tailoring, no legal review. | Renters splitting rent and furniture, few assets |
| Flat-fee online legal service | $200 to $750 | Moderate. Standardized but reviewed. | Modest shared finances, no real estate or business |
| Attorney-drafted, one lawyer | $500 to $2,500 flat | Strong, if disclosure is complete | A home, retirement accounts, or a clear income gap |
| Attorney-drafted, separate counsel each | Roughly double the above | Strongest | High assets, a business, kids from a prior relationship |
Add notarization of $10 to $100, often free or under $25 at a bank. Highly complex or contested situations may be billed hourly at about $250 to $450 per hour instead of flat fee.
You will see marketplace sites quote a flat-fee average near $590 to draft and around $380 to review, then turn around and cite "around $2,500" for an attorney elsewhere on the same site. Both are true. The first is a single standard agreement; the second is a tailored one, often with two lawyers. They are pricing different products, not contradicting each other.
Why the price swings by 10x
The cost tracks complexity and risk, not page count. A few specific facts about your life are what move you from the $50 row to the $2,500 row:
- Real estate. A home one of you owns, or one you buy together, means title, mortgage, equity, and a buyout-or-sell plan. That alone usually pushes you to an attorney.
- A business or professional practice. Valuing and protecting an ownership interest is lawyer work, full stop.
- Retirement and investment accounts. Separating what stays yours from what you build together takes careful drafting.
- A large income gap. If one partner earns far more or one leaves a career to support the household, support-on-separation terms get negotiated, and each side wants their own advocate.
- Separate counsel. The single biggest cost driver is also the single biggest enforceability upgrade: each partner hiring their own lawyer. It roughly doubles the bill and is usually worth it when real money is on the line.
What a cohabitation agreement must include
At its core the document answers one question in advance: if we split up or one of us dies, who gets what and who owes what. A solid agreement covers the items below. Copy this as your starting checklist.
Clause checklist
- Full legal names, the date, and a plain statement that you intend to remain unmarried
- Property each of you owned before moving in, kept separate
- Property acquired during the relationship, and whether it is separate or jointly owned
- The home: who holds title, who pays the mortgage, who builds equity, and what happens to it on a split (buyout formula or sale)
- Bank, retirement, and investment accounts, joint and separate
- How day-to-day income and expenses are split (rent, utilities, groceries, who pays what share)
- Debts: each partner's pre-existing debt and any jointly incurred debt
- Big purchases (car, furniture, appliances) and who keeps them on separation
- Pets: who owns them and who keeps them if you part ways
- Whether either partner provides financial support during the relationship or after separation, or expressly does not
- What happens on death, with a pointer to wills and beneficiary designations (the agreement alone does not transfer assets at death)
- Dispute resolution: mediation or arbitration, and which state's law governs
- An amendment-and-termination clause so you can update it or end it in writing
- A severability clause so one bad provision does not sink the whole agreement
- Signatures and the date, ideally notarized
What actually makes it hold up in court
A signed agreement is not automatically an enforceable one. Most ranking pages list clauses and stop. The five things below are what a judge actually looks at, and getting them right is the difference between a document that protects you and a souvenir.
- Put it in writing. Oral agreements between partners can be enforced in many states after Marvin v. Marvin, but proving the terms years later is close to impossible. Write it down.
- Give consideration that is not sex. A contract needs something of value exchanged on both sides. Under Marvin, an agreement "explicitly founded on the consideration of meretricious sexual services" is void. Base it on pooling earnings, sharing property, and dividing expenses, never on the relationship itself.
- Disclose finances fully and fairly. Both partners should lay out assets, income, and debts. Hiding a major asset is the fastest way to get the whole agreement thrown out later.
- Sign voluntarily. No pressure, no signing the night before a lease starts, no duress. Give each other time to read and think.
- Use separate counsel. Each partner having their own lawyer is the strongest signal that the deal was informed and fair. It costs more. It is also the single biggest enforceability upgrade you can buy.
What a cohabitation agreement cannot do
This is where careless pages get people hurt. Some attorney sites list "child custody and child support" as things the agreement "addresses," with no warning. That is misleading. Here is what your contract genuinely cannot control, no matter what you sign.
It cannot create a marriage or marital rights. Living together, even for many years, does not make you married in the roughly 40 states without common-law marriage, and a cohabitation agreement is a contract, not a marital status.
It cannot give your partner automatic inheritance or spousal tax treatment. Without a will, an unmarried partner inherits nothing under intestacy law, and the federal spousal tax breaks do not apply. The contract has to be paired with estate documents to fix this.
Does your state actually enforce it?
This is the question almost no competitor answers, and it is the most important one. Whether your agreement is worth the paper it is on depends on your state.
Most states follow Marvin v. Marvin (California, 1976), which held that express and implied agreements between unmarried partners to share property and earnings are enforceable, with the sex-as-consideration exception noted above. That is the majority rule.
A notable minority refuse on public-policy grounds. Illinois is the clearest example: in Hewitt v. Hewitt (1979) the Illinois Supreme Court held that enforcing property claims arising from a marriage-like relationship undermines the state's marriage laws. And this is not a dusty old case. The same court reaffirmed Hewitt in Blumenthal v. Brewer (2016), ruling that unmarried cohabitants still cannot enforce marriage-like property rights and that only the legislature can change that. So in Illinois, the usual cohabitation agreement faces real headwinds.
One more myth to kill, because it shows up in search results from foreign firms: there is no US rule that you "automatically become spouses after living together two years." That is a Canadian (British Columbia) regime, not American law. In the US the default is the opposite. Unmarried partners get nothing automatically, which is exactly why the contract exists.
The tax and inheritance gap nobody mentions
Every top cost page is silent on this, and it is where unmarried couples get blindsided. You are not spouses in the eyes of the IRS or your state's inheritance law, and that has hard consequences.
$19,000
2026 annual gift-tax exclusion per recipient. Transfers to a partner above this are taxable gifts (you may need IRS Form 709) because the unlimited marital deduction applies only to legal spouses, not to unmarried partners, registered domestic partners, or civil-union partners.
- No spousal transfer break. Move more than $19,000 in money or property to your partner in 2026 and you are making a reportable gift that eats into your lifetime exemption. Married couples have no such limit between them.
- No automatic inheritance. If you die without a will, your partner inherits nothing under intestacy, which passes to legal relatives. The house, the accounts, all of it can go to family you may be estranged from.
- Registered partners are still not spouses federally. A civil union or registered domestic partnership does not grant federal spousal tax treatment.
- So pair the agreement with an estate plan. A will, updated beneficiary designations on retirement and life-insurance accounts, a durable power of attorney, and a healthcare proxy. The cohabitation agreement divides assets; these documents actually transfer them and let you speak for each other in a crisis.
Which tier do you actually need?
Use this to size your spend before you call anyone. Work top to bottom and stop at the first row that fits.
| Your situation | What to do | Roughly |
|---|---|---|
| A home, a business, retirement accounts, a big income gap, or kids from a prior relationship | Attorney-drafted, separate counsel for each partner | ~$1,000 to $3,000+ |
| Meaningful shared finances but no real estate or business | One attorney, flat fee, with full disclosure on both sides | ~$500 to $1,500 |
| Modest shared rent, furniture, a joint account or two | Reputable flat-fee service or a template, then notarize | ~$0 to $750 |
Whichever row you land in, add two steps: confirm whether your state follows Marvin or, like Illinois, leans the other way, and pair the agreement with estate documents (will, power of attorney, healthcare proxy, beneficiaries).
General information, not legal or tax advice. US law varies by state and changes over time. We cite primary sources so you can verify everything, but for your own situation confirm with a qualified attorney or tax professional in your state. See our editorial & sourcing policy.
Common questions
Is a cohabitation agreement legally binding?
Do you need a lawyer to write one?
What is the difference between a cohabitation agreement and a prenup?
Can a cohabitation agreement cover child custody and child support?
Does living together for several years make you common-law married?
Does a cohabitation agreement need to be notarized?
Sources & further reading
- 1.IRS, Frequently Asked Questions on Gift Taxes (2026 annual exclusion $19,000; marital deduction for legal spouses only; not for registered domestic partners or civil unions)
- 2.Marvin v. Marvin, 18 Cal.3d 660 (Cal. 1976), Stanford SCOCAL official opinion record
- 3.Marvin v. Marvin, 18 Cal.3d 660 (Cal. 1976), Justia full opinion
- 4.Hewitt v. Hewitt, 77 Ill.2d 49 (Ill. 1979), Justia (Illinois Supreme Court)
- 5.Blumenthal v. Brewer, 2016 IL 118781, Illinois Supreme Court official opinion (reaffirms Hewitt)
- 6.Uniform Marriage and Divorce Act, Section 306 (separation-agreement terms binding on the court except those for support, custody, and visitation of children), Uniform Law Commission
- 7.In re Marriage of Hogsett & Neale, 2021 CO 1 (Colorado common-law marriage elements), Justia
- 8.Colorado Department of Revenue, Common Law Marriage (official state .gov)
- 9.Texas Family Code Section 2.401, Proof of Informal Marriage (official Texas statutes)