Co-Buying Mortgage Equity Splitter & Legal Planner
Unmarried couples or friends buying a home together often make unequal financial contributions. This tool models how home equity splits shift year-over-year as mortgage principal is paid down, and helps outline critical legal exit and buyout terms.
Reviewed by Marcus Vance, Senior Credit & Loan Policy Advisor — Last updated
Disclaimer: This application is a mathematical modeling and outlining tool. It does not constitute legal advice, representation, or a binding legal contract. Real estate statutes, title deed requirements, and cohabitation laws vary substantially by state and county. We strongly recommend that all co-buyers review the agreement blueprint generated by this tool with a licensed local family law attorney or real estate attorney before closing. All data stays client-side.
1 Property & Mortgage Details
2 Co-Buyer Financial Contributions
3 Co-Ownership Exit & Buyout Rules
Equity Split Timeline
Agreement Blueprint Worksheet
Copy this outline. It incorporates your calculated dynamic equity splits and selected exit rules, formatted to present to your real estate lawyer.
Unmarried Couples Home Purchasing Guide: Safeguarding Joint Assets
The Difference: Tenants in Common vs. Joint Tenancy
When purchasing a home as unmarried partners or friends, how you hold title is critically important:
- Joint Tenancy with Right of Survivorship (JTWROS): Owners hold equal 50% shares. If one owner passes away, their share automatically transfers to the surviving owner. It bypasses wills. This is the default structure for married couples but can be risky for unmarried buyers or friends.
- Tenants in Common (TIC): Allows unequal ownership ratios (e.g. 80/20) matching the actual financial contributions. If an owner passes away, their share does NOT go to the other owner; instead, it goes to their designated heirs via their will.
Why a Written Cohabitation Agreement is Mandatory
Unlike divorce laws, which provide a structured framework for dividing assets when a marriage dissolves, there is no standard legal code for separating assets when unmarried co-buyers break up. Without a written agreement, any disputes will likely result in expensive litigation (Partition Lawsuits) where a judge orders a forced sale of the house, and all proceeds are eaten up by legal fees.
A written TIC agreement details the buyout option, notice times, appraisal mechanics, and capital improvement tracking upfront, keeping you out of court.
Frequently Asked Questions
- What is a Tenants in Common (TIC) agreement?
- Tenants in Common (TIC) is a legal property deed structure that allows two or more people to own unequal shares of a property. Unlike Joint Tenancy (where ownership must be split 50/50 and automatically passes to the other owner upon death), TIC allows you to detail precise ownership percentages (e.g., 70/30) and leave your share to a designated heir through a will. Unmarried co-buyers should almost always use a TIC structure combined with a written co-ownership contract.
- How does the equity split shift if we pay mortgage payments equally?
- If Partner A pays 100% of the down payment, but both partners split the monthly mortgage payment 50/50, the equity split shifts over time. Initially, Partner A owns 100% of the home equity at closing. However, as Partner B contributes 50% of the monthly principal paydown, Partner B is acquiring equity. Over 15 or 30 years, Partner B's equity percentage will slowly climb, while Partner A's percentage will decrease from 100% toward a lower balance.
- Do capital improvements affect our ownership share?
- Yes, if one partner pays for a major capital improvement (like a $20,000 roof replacement or kitchen remodel), it increases the home's value. A co-ownership agreement should specify whether that partner receives a dollar-for-dollar credit to their equity share, or if the cost is split. This planner allows you to configure how capital improvements are credited.