financialwebtools.com• Apr 14, 2026• 1 min read
Show HN: Financial Web Tools – decision-focused calculatorsI built a set of lightweight financial decision tools (buy vs rent, house hacking, retirement, debt payoff) after trying to model a condo purchase for my girlfriend.Backstory: My girlfriend was looking into buying a condo, and I was trying to convey to her how the costs add up, even compared to renting. I knew from my personal experience with house-hacking in Seattle right out of college that the simple "renting is throwing money down the drain" philosophy can lead you to rush into buying properties without actually understanding the financial implications. I was having a tough time conveying this to her verbally, so I built a "house-hacking calculator" for her using Codex to visually model how investing a down payment and renting compares to buying a condo.Once I finished that initial prototype for her, I realized I had built something more generally useful. A lot of the available financial tools online are either overly complex for decisions like this (require modeling tax brackets,