Per IRS Publication 587, Business Use of Your Home (Including Use by Daycare Providers), on page 7:

Rent. If you rent the home you occupy and meet the requirements for business use of the home, you can deduct part of the rent you pay. To figure your deduction, multiply your rent payments by the percentage of your home used for business.

If you own your home, you cannot deduct the fair rental value of your home. However, see Depreciating Your Home, later.

Starting in tax year 2018, you can no longer deduct expenses for using your home as an employee as a miscellaneous deduction.

If you are self-employed and file Schedule C (Form 1040) Profit or Loss From Business, complete Form 8829, Expenses for Business Use of Your Home. The calculation is then transferred to Schedule C, Line 30.

To enter information for self-employed business use of home expenses in TaxAct:

1. From within your TaxAct return (Online or Desktop), click Federal. On smaller devices, click in the upper left-hand corner, then click Federal.
2. Click Business Income in the Federal Quick Q&A Topics menu to expand, then click Business income or loss from a sole proprietorship.
3. Click + Add Schedule C to create a new copy of the form or click Edit to review a form already created.
4. Continue with the interview process to enter all of the appropriate information.
5. On the screen titled Great! Let's get started on expenses for this business, click Enter expenses.
6. On the screen titled Did you use your home for business purposes for this business?, click Yes.

Note. When reviewing via the screen titled Your net income or loss for this business is $, click Review on the "Business Use of Home" row.

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.