Betterment tax (known also as “Capital Gains Tax” or “improvement tax”) is a ta
x levied on a real estate property seller, in accordance with the Land Taxation Law (betterment and purchase), 5723 – 1963.
If you're planning to sell your home or property, you want to make sure you calculated all your costs before and have a better estimate of how much you'll be able to keep in your pocket after all taxes an expenses.
Usually, the heaviest tax for the seller is the "mas shevach" (betterment tax) which requires a complex calculation.
Here are two links to options of how to get a very good estimate of that would be.