About this site
howmuchineedtoretire.com started from a simple frustration: most retirement advice tells you a rule of thumb ("save 15% of your income," "aim for 25 times your expenses") without ever turning it into a number you can actually check yourself, today, with your own numbers. So this site does one thing — it takes your actual monthly expenses, your age, and your timeline, and turns them into a concrete target and a concrete monthly savings plan.
What we built, and why
The retirement calculator uses the same math behind the well-known 4% rule, but lets you adjust the withdrawal rate and expected return yourself, rather than hiding the assumptions behind a single "recommended" number. We built a companion emergency fund calculator for the same reason — because retirement planning and short-term financial safety are really the same underlying question (how much do I need, and how do I get there?) applied to different time horizons.
Every article on this site exists to explain the reasoning behind a specific input in the calculator — the withdrawal rate, the expected return, the number of months of coverage — rather than being generic personal-finance content. If you can't find the "why" behind a number the calculator is using, that's a gap we want to fix; feel free to reach out.
How the calculators work
All calculations run entirely in your browser — nothing you type is sent to a server or stored anywhere. The math is standard time-value-of-money and compound interest formulas, the same ones used in financial planning software, just built into a free, ad-supported tool instead of a paid product. The methodology behind each number is explained in the site's articles, linked from each calculator.
What this site is not
This is not financial advice, and nothing here should replace a conversation with a licensed financial advisor who knows your full situation. It's a starting point for your own thinking — a way to turn a vague goal into a specific number you can plan around, adjust, and revisit as your life changes.
Get in touch
Found an error, have a suggestion for a new calculator, or want to point out something the site got wrong? We'd genuinely like to hear it — accuracy matters more to us than any single page looking polished. See the contact details in our Privacy Policy.