korWork

Stock option calculator

Estimate exercise gain, venture exemption and additional tax.

Your stock options

Use the exercise price in your grant agreement and the fair market value on exercise day.

For unlisted shares, use the value determined under applicable tax rules.

Annual limit: KRW 200,000,000

Company limit: KRW 500,000,000

Leave blank to omit the tax estimate.

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Exercise gain and estimated tax

What happens when you exercise?

Estimate exercise gain, the venture exemption and additional tax.

Tax rates and exemption sources · 2026

Checked 2026-09-23. This is reference information, not tax advice.

Frequently asked questions

What is exercise gain?
Market value per share on the exercise date minus exercise price, multiplied by shares exercised. A nonpositive difference yields no exercise gain.
What does the venture exemption cover?
For qualifying venture-company stock options, a portion of exercise gain may be exempt up to an annual and company-wide limit. Eligibility and grant conditions must be confirmed.
Is the tax estimate final?
No. It estimates incremental progressive income tax on the taxable exercise gain. Deductions, withholding, special payment options and capital gains tax on sale are excluded.