The answer isn't "as soon as you can afford it." It's "when the conditions are right for your specific situation."
Buying a home carries 3–5% transaction costs at purchase and 5–8% at sale. You need enough time and appreciation to recover those costs before the buy-vs-rent math tips in your favor. In most markets, that's 5–7 years minimum — often longer in expensive cities.
Divide the home price by annual rent for a comparable property. Below 15: buying generally makes more sense. 15–20: depends on your situation. Above 20: renting is often cheaper in the short to medium term. Many coastal US cities are above 25.
Beyond pure math, buying makes sense when you're confident in your location for 5+ years, have stable employment, and value the non-financial benefits of ownership (customization, stability, community). These matter and the calculator doesn't capture them.