All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is not an obligation on you to pay Zakaah on your share from the real estate that you had inherited from your grandmother, since it is fixed assets. In addition, fixed assets are not subject to Zakaah since they are undeveloping properties unless they are a form of merchandise. In which case, such assets will be subject to Zakaah at the same rate as articles of merchandise. Moreover, if such real estate is rented, then the revenue of its monthly rent is subject to Zakaah provided that:
1) Such a revenue reaches the value of Nisaab (the value of 85 grams of gold).
2) Such a revenue should be possessed by one for a complete lunar year.
Here, we draw your attention to the fact that if the house that you inherited was sold before and your share constituted a Nisaab, then you should pay the Zakaah for all previous years after selling, whether you took your share or not, taking into consideration the above-two conditions (1, 2).
Also, know that Zakaah is obligatory on any amount of money you have, since it is a developing property, but as mentioned above in conditions 1 and 2. Concerning the Nisaab and possessing it for a complete lunar year.
The rate of Zakaah is 2.5 percentage.
For more benefit on Zakaah, please refer to Fataawa 165375, 401332, and 379973.
Allah knows best.