Free, in your browser

Compound interest and FIRE calculator.

Move the sliders and watch a portfolio compound year by year, with contributions and interest side by side. Every number updates as you go, the full chart and table sit right below, and any calculation is one link away from a friend.

Want the year you reach FI, and how long the money lasts? That is what the app is for.

Portfolio · 2036Details ›
$0
Passive income $0 /mo
Start
Contributions
Interest
Projection details

Year by year

Year 102036
$0
Portfolio
This yearSo far
Start·
Contributions
Interest

Tap or drag across the chart to pick a year.

YearPortfolioContributionsInterest

Assumptions: annual compounding, deposits at the end of each month, no inflation, passive income at a 4% withdrawal rate. The same defaults as the app.

The app

Three questions. Three calculators. One app.

The calculator above is one of three in simpleFIRE. The app adds the two questions that come next, when you reach your target and how long the money lasts once you live off it, and then shows every number behind the answer: the chart you tap through year by year, the table, the assumptions.

Projection calculator: result card with portfolio value and passive income, sliders below
What will it grow into?

Projection

Starting portfolio, monthly contribution, period and annual return. Watch the portfolio compound year by year, with your contributions and the interest they earned side by side.

Time to FI calculator: years to target with the FI date and passive income
When do I get there?

Time to FI

Set your FI target and see the year and month you reach it, the passive income it pays, and how far along you are each year. Not sure of your number? The app estimates it from what you spend.

Drawdown calculator: how long the portfolio lasts and how much you can withdraw
How long will it last?

Drawdown

Start taking money out. See the year the portfolio runs dry, how much you can withdraw to last your whole planning horizon, and whether the returns outrun your withdrawals.

Everything in the app

Every number, explained.

The result is one tap from the year-by-year story behind it, and every assumption is a slider you can see and change.

Tap through the years

Drag a finger across the chart and the panel follows: contributions and interest for that year and so far.

Today's money or nominal

Inflation is one tap away on every calculator. Flip the main result between what the money will be worth then and what it buys today.

Share it as a PDF or a picture

A clean one-page report with the chart, the assumptions and the yearly table, or an image made for messages and social media.

Saved profiles

Keep several scenarios, a cautious one and a bold one, and switch between them in a tap.

Your assumptions, your rules

Compounding, contribution timing and yearly increases, withdrawal rate, planning horizon: every setting is a slider, and every result lists the ones it depends on.

Milestones on the chart

The year interest overtakes your deposits, the month you reach FI, the year the money runs out: flagged where they happen.

Dark, light, and yours

Two themes, your currency and number format, text that follows your accessibility settings.

iPhone, iPad and Mac

One app across all your Apple devices, with Split View and Slide Over on iPad.

Private by design

No account, no sign-in, no tracking. Your numbers never leave your device. Privacy policy.

Get simpleFIRE for iPhone, iPad and Mac.

Everything on this page, plus Time to FI and Drawdown, in your pocket.

Blog

The magic of compounding.

All posts
Ten years of waiting costs $651,000.Same deposits, same return, one decade later. In year 11, your money out-earns you.When interest quietly overtakes your deposits. A million isn't a million.What $1,000,000 buys after thirty years of 3% inflation.
What's new

Version 2.0

Full changelog
2.0
September 14, 2026

A completely new look, and two new calculators.

Every screen has been rebuilt around a result card you can read at arm's length, charts you tap through year by year, and a light theme if that's more your thing. The numbers have the same rigour as before; everything around them is new.

Also new

  • Time to FI and Drawdown join Projection: the year and month you reach your target, and how long the money lasts once you live off it.
  • Inflation, one tap away: flip the main result between today's money and nominal value.
  • PDF and image report: share any calculation as a document or a picture.
  • Planning horizon, a year-by-year table for every mode, and a new app icon.

Take the calculator with you.

simpleFIRE for iPhone, iPad and Mac. Your numbers stay on your device.