About Glidepath

Free calculators for people planning early or traditional retirement in the US, built to show their work.

Three ships on a distant horizon across a calm blue sea.
Photo: John Maravelakis on Unsplash

What it is

Glidepath is a set of retirement and FIRE calculators. Each one answers one question, shows how it got there and gives you a link that reopens it with your numbers.

A glide path is the course your money takes from today to the last year of retirement. Every chart on this site draws yours.

Octave Chanute, Orville and Wilbur Wright and three helpers sit in a row in front of the 1902 glider on the sand at Kitty Hawk.
The Wright brothers, friends and helpers with the 1902 glider, Kitty Hawk, North Carolina. The name comes from flying: a glide path is a steady descent to a safe landing. Photo: Lorin Wright, 1902, public domain.

How the math works

Today's dollars. We convert your expected return and inflation into a real return, (1 + return) ÷ (1 + inflation) − 1, and grow everything at that rate. Results compare directly with today's prices.

Contributions are added monthly, at the real monthly rate. Withdrawals are taken at the start of each year and rise with inflation.

Steady returns are assumed everywhere except the Monte Carlo calculator, which draws a random return for every year of every simulation from a fixed seed, so shared results are reproducible.

The trading floor of the New York Stock Exchange, with traders among banks of screens under an NYSE banner.
The New York Stock Exchange floor. Real returns vary year to year; only the Monte Carlo calculator lets them. Photo: Carol M. Highsmith, Library of Congress, public domain.

Not included: taxes, fees, Social Security and pensions, unless you account for them in your spending or withdrawal amounts. Each calculator page explains how.

Who it's for

President Franklin Roosevelt seated at a desk signing the Social Security Act, surrounded by lawmakers and Frances Perkins.
President Roosevelt signs the Social Security Act, August 14, 1935. Public domain, via Wikimedia Commons.

Anyone running the numbers on financial independence, and especially people who like to check them: every calculator offers a year-by-year table and a CSV download for your own spreadsheet.

Independence

A pilot flies a replica of the Wright brothers' 1902 glider low over a sand dune while spectators watch.
A replica of the 1902 glider flies again at Jockey's Ridge, North Carolina, 2002. Photo: Lt. Cmdr. Rick Haupt, U.S. Navy, public domain.

No bank, broker or fund owns Glidepath, and no calculator is built to steer you toward a product. Nothing here is financial advice; see the disclaimer.