What Is the 3-3-3 Rule in Real Estate?

The 3-3-3 rule is a personal-finance heuristic for home affordability that has spread through investor and homebuyer communities in several slightly different versions. Unlike lending standards set by Fannie Mae or FHA, it is not an official rule - it is a memorable shorthand, and it is worth knowing both what it commonly means and where it breaks down.

The Most Common Version of the 3-3-3 Rule

1. 1Spend no more than 3 times your annual gross household income on a home purchase price.
2. 2Keep at least 3 months of living expenses in reserve, separate from your down payment, before closing.
3. 3Keep your total monthly housing payment at or below roughly 3 weeks of take-home pay (a stand-in for keeping housing costs proportional to income).

Why the Numbers Vary by Source

Because the 3-3-3 rule is not codified by any lending body, you will find versions online that swap in a 20% down payment requirement, or use 3x income as a hard cap rather than a guideline, or apply it to investment property affordability instead of a primary residence. Treat any version as a sanity check, not a formula to plug numbers into and trust blindly.

Does the 3x Income Cap Work in DFW?

On a $90,000 household income, a strict 3x cap points to a $270,000 home, which is achievable in many DFW suburbs but tight in higher-demand areas like Southlake, Plano, or parts of Frisco. For investors specifically, the ratio matters less than whether the property cash-flows - a property priced above 3x your income can still be a good investment if the rent supports it, which is why this rule fits primary-residence affordability better than investment underwriting.