ESPP Stay-In Calculator

A frontend-only tool that compares the net dollar gain of two ESPP strategies for a participant whose plan runs Dec–May and Jun–Nov purchase periods:

1. Stay in the current Dec–May period (using prior-year IRS-limit rollover, possibly spilling into the current year's $25K cap).
2. Withdraw from the current period (forfeiting rollover) and deploy the full $25K cap into Jun–Nov.

You enter prices, growth assumptions for each period, your rollover, and your total contribution amounts; the app shows shares purchased, refunds from cap overflow, gross sell-immediately gain in each scenario, and a recommendation.

Develop

npm install
npm run dev

Test

npm test

Build

npm run build
npm run preview

Deploy

Import the repo into Vercel; framework preset Vite, build npm run build, output dist. No env vars.