If you are a freelancer, self-employed and/or have a home-based business, then you probably know to use Schedule C to itemize deductible expenses. There’s another tax form that you will want to use, Form 8829 (Expenses for Business Use of Your Home) are the main forms for home-based business owners.
From the Business Owner’s Toolkit:
Self-employed people must fill out a special form to claim the home office deduction. You must complete Form 8829, and then transfer the total to your Schedule C when you file your income tax return. Unfortunately, Schedule C-EZ, which is a much simpler form, can’t be used if you’re claiming the home office deduction. The business portion of your home mortgage interest and real estate taxes is claimed on Form 8829 and cannot be claimed again as an itemized deduction on Schedule A of your return.