ESPP Calculator

A qualified Employee Stock Purchase Plan lets you buy company stock at a discount, capped at 15% by the IRS. With a lookback provision, the discount applies to the lower of the share price at the start of the offering period and the price on the purchase date. So your purchase price is min(offering price, current price) times (1 minus the discount). The lookback is what makes ESPPs especially valuable when the stock rises during the offering period.

First the calculator finds the discount reference price. With a lookback that is the lower of your offering-date price and current price; without one it is simply the current price. It then multiplies that reference by (1 minus your discount percent). For example, a 15% discount on a 50 USD reference price gives a purchase price of 42.50 USD per share.

Your total contribution is your salary times your contribution percent times the fraction of the year the offering period covers (months divided by 12). The calculator divides that contribution by the purchase price and rounds down, because plans buy whole shares. Any cash left over is shown separately and is usually refunded or carried into the next period.

The return is your immediate paper gain divided by the cash you actually invested in shares. The gain is the market value of your shares at the current price minus what you paid for them. It shows the built-in profit on purchase day if you could sell right away, before any taxes or trading costs.

No. It shows the pre-tax discount, gain, and return only. It does not model the IRS 25,000 USD annual purchase limit, ordinary income on the discount, or capital gains rules for qualifying versus disqualifying dispositions. Your real outcome depends on how long you hold the shares and your tax bracket.

No. It is an educational estimate to help you understand how your plan's discount and lookback affect your purchase. Actual results depend on your plan's exact terms, share price movements, fees, and taxes. Treat the numbers as a planning starting point, not financial or tax advice, and confirm details with your plan documents or a qualified advisor.