Hey PH! I'm Alex. A few years ago, I was carrying $80K across 7 credit cards. COVID, family health, life — it adds up fast. I never missed a payment in two decades, but I was burning $1,400/month in interest alone. I was throwing extra cash at whichever card "felt" right, with zero math behind it. So I did what any developer does: I opened Excel. But for 7 cards with different APRs and complex allocation rules, it became a mess. I rebuilt it in .NET with actual charts, and that's when I saw something that stopped me cold. One of my balances was actually going UP. My cash advance balance (29.99% APR) was generating $125/month in interest. Because of how the CARD Act works, my payments were hitting my 17% purchase balances first while the high-interest debt just compounded. That $9,800 sub-balance would have taken 25 years to pay off, costing me $38,000 in total. I checked NerdWallet and Credit Karma — none of them track Purchase vs. Cash Advance APR separately. They don't show you the real math of where every dollar goes. So I built Senaro. It started as a personal tool and is now a free web app. Separate APR Tracking: Track different APRs on a single card — purchase and cash advance separately. Side-by-Side Comparison: Compare Avalanche vs. Snowball with your actual numbers. Privacy First: No signup, no backend, no data collection. Everything stays in your browser's localStorage. I've paid off half my debt since I started using this. It didn't change my income; it changed my visibility. The core calculator will always be free. I'm currently working on Pro features like AI-powered "what-if" scenarios and PDF exports. Full story with charts: https://senaro.ai/blog/why-i-bui... I'd love your feedback: What's the one thing about your credit card debt that's hardest to get clarity on?

Senaro

Free credit card payoff calculator + cash advance tracking

Free credit card payoff calculator + cash advance tracking