About the ESPP Calculator
This ESPP calculator shows exactly what your employee stock purchase plan earns you. Enter how much you contribute during an offering period, the plan discount (often 15%), whether the plan has a lookback, and the share price at the start (offering date) and end (purchase date). It calculates the purchase price, how many whole shares you get, your profit if you sell, and the return on the money you put in.
It is meant for employees deciding whether to enrol, how much to contribute, and whether to sell immediately or hold. With a 15% discount and a lookback, the plan price is 85% of the lower of the two prices, so a rising stock can produce returns far above 15% in just six months.
The tax estimate follows US rules for qualified Section 423 plans. A quick sale is a disqualifying disposition: the bargain element at purchase is ordinary income and any extra gain is treated as a short-term capital gain. A qualifying disposition (held two years from the offering date and one year from purchase) limits ordinary income to the smaller of the actual gain and the discount on the offering-date price, and taxes the rest at long-term rates.
With the default inputs, the pre-tax profit is $3,520.00. Change any value above to recalculate instantly.
How to use the espp calculator
- 1Enter the total contributions withheld during the offering period.
- 2Set the plan discount and turn the lookback on if your plan uses the lower of the start and end prices.
- 3Enter the share price on the offering date and on the purchase date.
- 4Enter your sale price and choose whether you sell right away or hold for a qualifying disposition.
- 5Add your tax rates to see the after-tax profit and return.
Formula and method
The plan applies the discount d to the purchase-date price P₁, or — if there is a lookback — to the lower of the offering-date price P₀ and P₁. Your accumulated contributions C buy as many whole shares as possible; the leftover cash is typically carried into the next period or refunded. Profit is the sale value minus what you paid, and return is profit divided by the cost of the shares.
For a disqualifying disposition, the bargain element (P₁ minus the purchase price, per share) is ordinary income and the rest of the gain or loss is a capital gain, assumed short-term and taxed at your ordinary rate. For a qualifying disposition, ordinary income is the smaller of the actual gain and the discount applied to the offering-date price (d × P₀ per share); the remainder is a long-term capital gain.
- d
- Plan discount (e.g. 15%)
- P₀, P₁
- Share price on the offering and purchase dates
- C
- Contributions for the period
- S
- Sale price per share
Worked examples
15% discount with lookback, stock rises from $40 to $50, sold immediately
The lookback uses the lower $40 price, so you pay 85% × $40 = $34. $7,500 buys 220 whole shares for $7,480, with $20 carried over. Selling at $50 gives a $3,520 profit — a 47% return. In a quick sale the whole $3,520 bargain element is ordinary income, taxed at 24% ($844.80), leaving $2,675.20.
No lookback, falling stock
Without a lookback the discount applies to the $45 purchase-date price: 0.85 × $45 = $38.25. $7,500 buys 196 shares for $7,497. Selling at $45 earns $6.75 per share, or $1,323 — the guaranteed 17.6% return from a 15% discount.
Qualifying disposition after the stock climbs to $70
Holding the 220 shares until they qualify and selling at $70 gives a $7,920 profit. Ordinary income is limited to the 15% discount on the $40 offering price: 220 × $6 = $1,320, taxed at 24% ($316.80). The remaining $6,600 is a long-term gain taxed at 15% ($990), so total tax is $1,306.80.
Frequently asked questions
How does an ESPP lookback work?+
A lookback sets the purchase price using the lower of the share price on the first day of the offering period and on the purchase date, then applies the discount. If the stock rises during the period you get the discount on the older, lower price.
Should I sell ESPP shares immediately?+
Selling right away locks in the discount (at least 17.6% on your money with a 15% discount) and avoids concentration risk in your employer’s stock. Holding for a qualifying disposition can lower the tax rate on further gains but exposes you to price drops.
What is the ESPP contribution limit?+
Under Section 423 you can buy no more than $25,000 worth of stock per calendar year, measured at the offering-date price before the discount. Plans also usually cap payroll contributions at 10–15% of pay.
How is ESPP taxed?+
You pay no tax at purchase. When you sell, part of the gain is ordinary income (reported on your W-2) and the rest is a capital gain or loss. How much is ordinary income depends on whether the sale is a qualifying or disqualifying disposition.
Why is my return higher than the 15% discount?+
A 15% discount means you pay 85 cents for each dollar of stock, which is a 17.6% return on your money (15 ÷ 85). A lookback on a rising stock adds the price increase since the offering date on top of that.
What happens to leftover contributions?+
Plans buy whole shares (and sometimes fractional shares). Money left over after the purchase is usually rolled into the next offering period or refunded to you without interest.
Tax results are estimates based on published rules and simplified assumptions. They are not tax advice — check official guidance or a tax professional for your situation.