Runway: Financial Calculator

Your savings rate is the one number that actually moves your FI date. Not your net worth. Not your budget categories. Your savings rate. Runway calculates it every month - and tracks the gap between what you planned to save and what you actually saved. That gap becomes your Flex Fund: a guilt-free buffer you can draw on next month, or let compound over time. *WHAT RUNWAY DOES Every month, you open Monthly Close. You enter your take-home income, set your savings rate target, and log your spending. Runway calculates your actual savings rate in real time, shows you the flex delta (how far above or below target you landed), and locks the month when you're done. No going back. The Flex Fund tracks every locked month cumulatively. Come in under target in April? You've earned a cushion to spend in May. Go over in June? It draws down. It resets the guilt cycle that makes most budgets collapse. *THE COCKPIT Open the app and you see one number: your savings rate. Below it, your Flex Fund balance and your Financial Independence date - calculated in real time from your current net worth, your locked spending history, and the 4% withdrawal rule. The FI date isn't a fantasy projection you set once and forget. It recomputes every time you lock a month. Spend less → the date moves closer. The feedback loop is immediate. *PULSE: TRACK YOUR PROGRESS Lock three months and your history starts showing up. The savings heatmap maps every month - green when you came in under target, red when you went over, scaled by how far. Tap any month to see the breakdown. The Insights section shows your savings rate trend, income trajectory, spending pattern, and how your Flex Fund has grown over time. Including the questions most apps won't ask: which month do you consistently overspend? Is your income actually growing? Beginner mode shows the three most useful cards. Expert mode shows all eight with moving averages. *FIRE TRAJECTORY (PRO) The trajectory chart projects your net worth across 30 years using compound interest, real return assumptions, and your actual locked data. Three what-if levers let you model scenarios in real time: - Savings rate slider - drag it up and watch your FI year move - Income growth - add 2% annual raises and see the decade it buys you - Allocation preset - conservative, balanced, or aggressive The year delta pill shows how many years each change saves or costs. The math is the 4% rule. The data is your own. *WHAT RUNWAY ISN'T Not a budgeting app. Not a bank sync. Not a subscription. There are no accounts. Your data lives on your device in a local SQLite database. Nothing leaves your phone. Runway Pro is a single one-time purchase - yours forever. *RunwayPRO Unlock for $9.99 (one-time): - FIRE Trajectory chart + 30-year projection - Three what-if levers (savings rate, income growth, allocation) - Full Pulse insights (9 charts, seasonality, year-over-year) - Savings Rate Card - a shareable for the moments you want to show your rate - CSV export of all locked months *DESIGNED FOR THE FIRE COMMUNITY If you've ever used a spreadsheet to track your savings rate month by month, Runway is that spreadsheet - built as an app, without the maintenance. Privacy-first. No ads. No tracking. Just the numbers that matter. runway · track your rate