You can tax deduct using form 8829:https://www.irs.gov/pub/irs-pdf/... However home office with declared area above 30% and 300 sq ft, and/or expenses above $5k deduction will more likely attract the IRS attention. In particular especially if you have significant source of other income from forms W2 , and to less degree from 1099 Misc. You can deduct proportionally property tax, mortgage interest, insurance, maintenance, also you can add depreciation of home value often around 2.5%/yr(you will need a special excel table for that), utilities, and casualty losses, etc.50% use for home office probably will be a red flag. Allowable percentage also will depend on the code you use for the type of activity that your business is involved in.Also consider using form 4562 with section 179 for other business assets depreciation.