About This Site
Free, privacy-first financial tools built for people who want to understand their money.
Why This Site Exists
Personal finance math is not complicated — but most tools that do it are locked behind paywalls, cluttered with ads, or require you to hand over an email address just to run a calculation.
This site exists to change that. Every calculator here runs entirely in your browser. No data is sent to a server. No account is required. No spreadsheet skills needed. You put in your numbers, you get your answer, and you keep your privacy.
The goal is simple: help people understand the math behind saving, investing, and reaching financial independence — so they can make better decisions for their own lives.
What You'll Find Here
This site offers a growing set of free tools and educational resources covering compound interest, retirement planning, and the FIRE (Financial Independence, Retire Early) movement.
Compound Interest Calculator
The core tool on this site. Enter an initial deposit, monthly contribution, interest rate, and time horizon. See an interactive chart showing exactly how your principal and interest grow year by year, along with your final balance.
FIRE Dashboard
A comprehensive retirement planning tool. Track your progress toward your FIRE number, model optimistic and pessimistic return scenarios, explore the impact of mortgage paydown, and see how small changes in savings rate dramatically shorten your timeline.
Coast FIRE Calculator
Coast FIRE is the idea of saving enough early that compound growth alone carries you to retirement — without another dollar of contributions. This calculator finds your Coast FIRE number and shows how far along you already are.
FI Insights
Data-driven context for your financial journey. Savings benchmarks by age, millionaire statistics, the first $100K phenomenon, and an interactive Rule of 72 explorer — all in one place.
Our Philosophy
Privacy First
Every calculation runs locally in your browser using WebAssembly. We never see your numbers. We don't store them, transmit them, or log them. Your financial situation is yours alone. We use Google Analytics to understand which tools are most useful (page views, not personal data), and Google AdSense to keep the site free. See our Privacy Policy for full details.
Education Over Sales
Nothing on this site is financial advice, and nothing here is trying to sell you a product. We don't recommend brokers, push affiliate links for financial products, or suggest you buy anything. The calculators are educational tools. Use them to build intuition, run scenarios, and ask better questions of a qualified financial advisor if you need one.
Free, Always
Every tool on this site is and will remain free. The site is supported by non-intrusive display advertising. If you'd like to support the project directly, there's a link in the footer. No pressure either way.
Who Is This For?
These tools are useful for anyone at any stage of their financial journey:
Beginners who want to understand why "start saving early" actually matters — the compound interest calculator makes it visual and tangible.
Mid-career savers who want to know if they're on track and how much longer they need to keep working at their current pace.
FIRE enthusiasts modeling aggressive savings scenarios, exploring Coast FIRE, or stress-testing their withdrawal strategy against different return assumptions.
Parents and educators looking for a clear, jargon-free way to demonstrate the power of compounding to younger people.
A Note on Accuracy
The calculators on this site use standard financial formulas for compound interest and retirement projections. They are designed to give you accurate ballpark figures for planning purposes.
That said, real-world investing involves taxes, fees, variable returns, inflation, and life events that no calculator can fully model. The numbers you see here assume constant rates and no withdrawals during the accumulation phase. Treat the results as directional guidance — a starting point for planning, not a guarantee.
For major financial decisions, always consult a qualified financial professional. See our Terms of Service for full disclaimers.