How is zakat calculated for a house still under construction, another plot of land intended for residence, a plot of land for which a down payment has been made for commercial purposes, and a sum of money that has not yet reached its due date, knowing that the end of the hawl (zakat year) is on the Day of Ashura? Was it a mistake not to pay Zakat al-Fitr for yourself when you were employed before marriage, and what do you do now regarding Zakat al-Fitr after marriage?

Zakat (definition) is obligatory on lands designated for sale and purchase, as they are considered trade goods, but it is not obligatory on land designated for building a residence.

Your zakatable assets are the land you intend to sell for profit and the amount of money you possess. The value of the land is calculated on the day the hawl (one lunar year) is completed, and the existing money is added to it. Zakat is then paid at a rate of a quarter of a tenth (2.5%) of the total, provided you have no debts.

If there are debts, you should look at the assets exceeding your needs to cover those debts. If they suffice, then all your zakatable wealth is subject to zakat. If they do not suffice, you deduct the amount that was not covered, then pay zakat on the remaining amount.

As for Zakat al-Fitr, it is obligatory upon an unmarried woman who possesses what is sufficient for her sustenance. Her father or someone else may pay it on her behalf, provided she is informed and consents. If her father paid it in past years without informing her, she must pay it for all those years. After marriage, the husband becomes responsible for paying it.