LoanLab

LoanLab is a calculator for people juggling more than one loan at a time — credit cards, auto, student, personal, a mortgage — who want to see exactly what an extra monthly payment does to their debt, not just guess. Add each loan's balance, interest rate and minimum payment, and LoanLab computes a real amortization schedule for it: monthly payment breakdown, payoff date, and total interest at minimums. The core of the app is the extra-payment simulator. Set one shared extra amount you could put toward debt each month and pick a strategy — avalanche (highest interest rate first, the mathematically optimal order) or snowball (smallest balance first, for faster early wins). LoanLab runs a real month-by-month simulation of every loan together as a single system: once a targeted loan is paid off, its freed-up minimum payment automatically rolls into the pool going toward the next loan in line, for every month after — not a fixed split calculated once and left alone. The signature PayoffRace widget animates every loan's balance shrinking toward zero in parallel, highlighting whichever loan is currently receiving the extra payment so the handoff between loans is visible as it happens. Every result is compared against a minimums-only baseline — total interest saved and months saved by committing that extra payment — and, with more than one loan, avalanche and snowball are run side by side on the same numbers so you can see which strategy actually saves more for your specific situation. A Stats screen tracks total debt remaining, interest paid per loan, a category breakdown, and a 12-week activity heatmap. LoanLab is a personal calculator, not financial advice, a lender, or a credit product — it computes the consequences of numbers and a strategy you choose, and never tells you what to do. Key features: • Track multiple loans side by side: balance, rate, minimum payment, category • Real amortization schedule and payoff date per loan • Unified extra-payment simulator with avalanche or snowball strategy • Automatic rollover — a paid-off loan's minimum payment feeds the next loan's payoff • PayoffRace: animated parallel balance bars showing the strategy playing out • Baseline comparison: total interest saved and months saved vs. minimums-only • Side-by-side avalanche vs. snowball comparison for the same extra amount • Stats screen with debt breakdown, interest-per-loan chart, and activity heatmap • Fully offline — all loan data stays on your device