ProjectionLab

ProjectionLab isn’t trying to replace your day-to-day budgeting app, it’s meant to sit on top of one. You enter your current accounts, income, and expenses by hand, then build out scenarios: retiring at 55 instead of 65, a career break, buying a second property, and the app runs Monte Carlo simulations against each one to show a range of likely outcomes rather than a single optimistic line going up and to the right.

That scenario-branching approach, where you can fork a plan and compare two futures side by side, has made it a favorite in financial-independence forums where people obsess over exactly this kind of long-range modeling. The free tier covers basic projections, Premium costs around $129 a year and opens up the full scenario and simulation toolkit, and a Pro tier near $549 a year adds more advanced modeling for people managing more complex finances. It suits someone who already tracks day-to-day spending elsewhere and wants a serious answer to “am I actually going to be okay in 20 years,” not someone looking for an everyday budget app.