Review your FIRE and Coast assumptions
Connect your own spending, time horizon and growth assumptions with the capital required by a constant annual model. The calculator starts with prefilled, editable model assumptions and a result. These are not an actual quote, company accounts or recommended values. Edit the inputs and recalculate; Restore example returns to the initial assumptions.
1. Enter your own consistent assumptions
Open FIRE & Coast FIRE in Financial calculators. Enter current capital, annual spending at today’s prices and the years to your target date. Choose one currency for all amounts. This choice labels the amounts and does not convert them. Enter 0 explicitly for zero capital, spending or inflation.
Supply annual inflation, an effective annual accumulation return and your assumed annual withdrawal fraction yourself. Effective return describes one annual growth factor. These fields are not populated from market history or a suggested safe rate. Valid negative growth or inflation remains negative.
2. Read the target and annual contributions
The target capital divides spending at the future price level by your withdrawal fraction. Coast capital discounts that target through your assumed annual growth to today. The existing capital projection shows growth without additions. The remaining gap determines equal contributions added at each year end.
Calculate scenario produces one result for the totals and annual table. The required annual contribution rounds upward to cents, and that same amount drives the table. Editing an assumption hides the old result until the next explicit calculation. Expand exact detail for the original decimal values, method and actual calculation time.
3. Keep a scenario separate from a retirement forecast
This model covers the years before the target date. It does not simulate retirement withdrawals, longevity, changing returns, sequence of returns, tax or fees. It supplies neither a probability of success nor a safe withdrawal rate. Changing your assumptions changes the arithmetic rather than verifying a forecast.
This is a guide to Datisto. Private features require sign-in and access to your own data. Personal models use your assumptions; availability and permitted use of source data are checked with the particular result. This is not investment advice.