Checkout Calculator: Can you check out?

A browser-based retirement planning tool that estimates the lump sum principal required to fund your current lifestyle for the rest of your life.

This calculator models annual spending, increasing late-life healthcare costs, taxes, market return scenarios, and inheritance goals to estimate how much capital would be required to retire today.

The tool can be accessed at the following URL:

https://keithbar.github.io/CheckoutCalculator/

How it works

This app:

• Projects yearly spending from current age to projected death
• Gradually increases spending at user-defined intervals to simulate age-related healthcare costs
• Applies state and federal tax assumptions
• Simulates different market return scenarios (optimistic, average, pessimistic)
• Works backward to determine the minimum principal required today

Tech stack

• React (functional components and hooks)
• Vite (build tool and dev server)
• JavaScript (ES6+)
• CSS

Fully client-side; no backend or database.

Assumptions and limitations

This tool:

• Does not model inflation separately (all values are assumed in today's dollars, with market returns adjusted accordingly)
• Uses simplified tax and return assumptions
• Does not provide financial advice

Running locally

If you'd like to run it locally yourself:

npm install
npm run dev

Then open the local development URL shown in your terminal.