About How Long Will It Last

The question "will this money last?" comes up at some of the most consequential moments in a person's life: the year before retiring, the month after inheriting, the week a job ends. At exactly those moments, the answers available online are frustrating — an article that circles the topic without ever producing a figure, a calculator gated behind a contact form, or a planning suite that demands an hour of setup.

None of that is warranted by the underlying maths, which is a monthly loop over a single balance. So the design principle here is that the answer appears immediately, every assumption behind it is visible and editable, and the explanation of how it was produced sits right below the tool.

Each calculator runs entirely in your browser. There is no account system, no server-side storage of your figures, and no transmission of what you type. That is partly a privacy decision and partly a simplicity one: a tool that keeps nothing cannot lose anything.

The models use standard, well-documented financial arithmetic — monthly compounding, ordinary annuity payment formulas for solving withdrawals, and conventional amortisation for the mortgage tool. Nothing is proprietary. The methodology page sets out the shared approach, and each calculator restates the specifics for its own case so you can reproduce any result yourself.

Content and calculations are written and maintained by the site's operator. We do not publish articles under invented author bylines or claim professional review that has not taken place. Where a topic requires licensed expertise — individual tax treatment, estate planning, product selection — the pages say so and point you toward a qualified professional rather than guessing.

They are educational models. They take the assumptions you supply and show you their consequences with more precision and less effort than a spreadsheet would. Used well, they change how you think about a decision: you see that spending is usually a bigger lever than return, or that an extra $200 a month removes years from a mortgage.

They are not forecasts, and they are not advice. They cannot know your tax position, your health, your job security, or next decade's markets. A projection that says thirty years is telling you what a steady-state model implies, not what will happen. Treat the result as the beginning of a conversation — with a partner, or with someone qualified to advise on your specific circumstances.

If you find a calculation that looks wrong, an explanation that is unclear, or a scenario the model handles badly, we want to hear about it — corrections to the maths take priority over everything else. Use the contact page. We cannot answer questions about your personal finances, and we will not pretend otherwise.