Prenup vs Cohabitation Agreement in Canada: Which One Do You Need, and When?

If you're moving in together, getting engaged, or planning a wedding, you've probably run into two terms that sound similar but aren't quite the same:

• Prenup (often called a marriage contract in Canada)
• Cohabitation agreement (for couples living together who aren't married)

They both exist for the same reason: to help couples get aligned about money and expectations while things are good, instead of trying to negotiate in the middle of a breakup or a crisis.

This article is general information, not legal advice. Family law rules and terminology vary by province, and your personal situation matters. The goal here is to help you choose the right starting point and avoid common confusion.

If you only read one section: the decision tree

1) Are you married (or getting married soon)?

If yes, you're usually looking for a prenup / marriage contract.

• If you haven't married yet: it's commonly called a prenup
• If you're already married: it's still typically a marriage contract, just signed after the wedding (sometimes called a postnup)

2) Are you not married, but moving in together (or already living together)?

If yes, you're usually looking for a cohabitation agreement.

3) Are you not married now, but plan to marry later?

Many couples do both, in sequence:

• Cohabitation agreement now (before or shortly after moving in)
• Update it later, or transition it into a marriage contract when you marry (how this works depends on the province)

First, a quick language translation (because Canada is confusing)

People use "prenup" as a catch-all, but in Canadian law and practice you'll see terms like:

• Marriage contract (very common in Canada)
• Cohabitation agreement
• Domestic contract (a broader category in some provinces)
• In Quebec, you'll also see marriage contract (notarized) and contrat de vie commune for de facto unions

So if you're Googling and nothing feels consistent, it's not you. It's the vocabulary.

What is a prenup in Canada?

A "prenup" is generally an agreement made before marriage that sets expectations about financial and practical issues, like:

• what happens to property if you separate
• how you'll handle debts
• support expectations (in plain language: whether one person would help financially if the relationship ends)

In Ontario, for example, the Family Law Act describes a marriage contract as an agreement between people who are married or intend to marry, covering rights and obligations under the marriage or on separation or death, including property and support.

What is a cohabitation agreement?

A cohabitation agreement is for couples who live together (or plan to) but aren't married.

It's especially useful when you're making "big life" moves like:

• moving into one partner's home or condo
• buying furniture or a car together
• merging finances or opening joint accounts
• planning for one partner to take time off work
• moving cities or changing jobs for the relationship

In Ontario, the Family Law Act specifically describes a cohabitation agreement as an agreement between people who are cohabiting or intend to cohabit, and aren't married to each other, covering rights and obligations during cohabitation or if you stop cohabiting or on death.

The real difference: relationship status and timing

Here's a simple comparison that's accurate in spirit across Canada, even though the details vary province to province.

A key Canada nuance: "common-law" can mean different things in different places

One reason couples end up on Prenuply is simple: they assume "common-law" automatically means "same as married."

That is sometimes true for some purposes, and not true for others. Even federally, the tax definition is different from provincial family law definitions.

For example, the Canada Revenue Agency describes "living common-law" (for tax) as living in a conjugal relationship for at least 12 continuous months (with additional criteria also possible).

Meanwhile, in British Columbia, the Family Law Act defines "spouse" to include people who have lived in a marriage-like relationship for at least 2 years (and it also includes a child-related rule for some parts of the Act).

The takeaway: your agreement choice should follow your province's family law reality, not just the label "common-law."

Province callouts (Ontario, BC, Alberta, Quebec)

These are not "everything you need to know" summaries. They're the specific details that most commonly change what couples need.

Ontario: cohabitation agreements can turn into marriage contracts

Ontario's Family Law Act:

• describes marriage contracts (section 52)
• describes cohabitation agreements (section 53)
• says that if the parties to a cohabitation agreement marry each other, the agreement is deemed to be a marriage contract (section 53(2))
• says a domestic contract is generally unenforceable unless it's in writing, signed, and witnessed (section 55)

Practical meaning: if you're moving in now and marrying later, a cohabitation agreement can be a sensible "start now" step.

British Columbia: "spouse" can include common-law after 2 years

BC's Family Law Act defines "spouse" to include someone who has lived in a marriage-like relationship for at least 2 years.

BC also emphasizes that you can make a written agreement about property and debt at any time, and if it's signed and witnessed, courts will likely not change it.

Practical meaning: in BC, the timing of when you become "spouses" for certain rights can matter, which is exactly why many couples choose to write things down early.

Alberta: "common-law" is often an adult interdependent relationship

In Alberta, many people use "common-law," but legislation often uses "adult interdependent partner" language. The Adult Interdependent Relationships Act sets out ways you can become adult interdependent partners, including living together in a relationship of interdependence for at least 3 years, or having a child, or entering into an adult interdependent partner agreement.

Alberta also has specific formal requirements for agreements dealing with property division, including acknowledgements made before separate lawyers (often discussed under the Family Property Act).

Practical meaning: the "paperwork steps" can matter more in Alberta than couples expect, so it's worth planning your process carefully.

Quebec: marriage contracts are notarized, and de facto unions are treated differently

Quebec's government guidance states:

• A marriage contract must be notarized and signed before a notary
• You can sign it before or after marriage

Quebec's Directeur de l'état civil also notes that de facto spouses do not have the same rights and responsibilities as spouses in a marriage or civil union, regardless of how long they live together.

Quebec also uses the term contrat de vie commune as a written agreement for people living together in a de facto union.

Practical meaning: Quebec couples often benefit from getting clear early about which union type applies, because the default legal framework differs.

Real-life examples: which agreement fits?

Scenario 1: "We're moving into my condo"

Most couples in this situation want a cohabitation agreement, even if marriage is on the horizon.

Why? Because moving into an owned home changes day-to-day finances fast:

• Who pays what?
• Are payments "rent," contributions, or something else?
• What happens if you break up after renovations?

Scenario 2: "We're engaged and already living together"

You can choose either path depending on timing:

• If the wedding is soon, you might go straight to a marriage contract
• If the wedding is far away and you're making big financial moves now, a cohabitation agreement can be a useful bridge

Scenario 3: "We're not sure we want to marry, but we're building a life"

Cohabitation agreement, almost always.

It's for couples who want clarity without needing marriage as the trigger.

Scenario 4: "One of us has debt, the other has savings"

Either agreement can help, depending on marriage plans.

The point isn't to shame debt or protect one person from the other. It's to prevent resentment and misunderstandings later.

Scenario 5: "We're in Quebec and want to choose our matrimonial regime"

You're likely looking at a notarized marriage contract, and it's worth understanding the difference between marriage, civil union, and de facto union.

What these agreements can cover (in plain language)

Not legal advice, just the conversation topics couples most often include:

Money and property

• What you each bring into the relationship (assets and debts)
• How you'll handle shared purchases
• What happens if you split up
• What happens if one person pays more for housing

Support and lifestyle expectations

• How you handle career changes
• How you handle a period of unemployment
• What happens if one person takes time off work for caregiving

Process and communication

• How you'll revisit the agreement after major life changes (kids, relocation, buying a home)
• How disputes will be handled (for example: "we agree to talk first, then mediate")

What agreements usually can't "solve" on their own

Most couples want certainty on everything, but child-related issues are often treated differently under Canadian law.

For example, in Ontario the Family Law Act makes it clear that provisions in a marriage contract or cohabitation agreement about decision-making responsibility or parenting time aren't enforceable in Ontario.

Practical takeaway: you can talk about values and intentions, but you should be cautious about assuming a contract can lock everything in.

When should you do this?

A good time is when you're making a "threshold decision":

• moving in together
• buying property
• getting engaged
• planning a wedding date
• starting a business
• deciding one partner will take time off work

If you wait until emotions are high (wedding stress, family conflict, or relationship strain), everything gets harder.

If you want a step-by-step timeline and prep list, see our Canadian Prenup Checklist.

A simple, low-drama process to get started

1. Have the conversation first Start with goals: fairness, clarity, and reducing future stress.

2. Do basic financial disclosure (to each other) List assets, debts, income, and major obligations. You don't need perfection to start, but you do need honesty.

3. Draft a first version This is where templates are valuable: they turn "big emotional topics" into structured decisions.

4. Take time Sleep on it. Re-read it. Make edits.

5. Finalize in a way that matches your province Some provinces emphasize things like witnesses, notaries, or lawyer acknowledgements more than others.

Where Prenuply fits

If you've read this far, you're probably the kind of couple who wants to do this thoughtfully and without drama.

Prenuply is designed to help you turn your decisions into a structured draft quickly, so you can focus on getting aligned with your partner instead of starting from a blank page.

If you're ready to create a first draft:

• Visit Prenuply.ai
• Choose your province and situation
• Generate a template you can review and refine together

Related reading

• What is a Prenuptial Agreement in Canada? A Complete Guide
• Prenup Laws by Province: Ontario, BC, Alberta & Quebec Guide
• How Much Does a Prenup Cost in Canada? 2026 Price Guide
• The Canadian Prenup Checklist: Timeline, Documents, and Questions to Ask
• How to Talk About a Prenup Without Starting a Fight
• Is Wanting a Prenup a Red Flag? What It Actually Says About Your Relationship