I have been supporting my fiance since 2018 for an ongoing workman's comp injury she suffered. Can I claim her as a dependent?

[bradfisher_99]

We live in same household whereas I maintain all the bills, groceries, mortgage. She is unable to drive, shop etc.

[DoninGA]

You can claim a non-relative as a dependent if they meet all the requirements under the Qualifying Relative rules.

To be a Qualifying Relative -

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.
2. The person either (a) must be related to you or (b) must live with you all year as a member of your household.
3. The person's gross income for the year must be less than $4,300 (social security does not count) in 2021
4. You must provide more than half of the person's total support for the year.
5. The person must be a U.S. citizen or a U.S., Canada, or Mexico resident for some part of the year.
6. The person must not file a joint return with their spouse.

[Hal_Al]

Nontaxable Social security and workers compensation doesn't count as income, for the income test, but that money she spends on her self does count as support not provided by you, for the support test. Money she puts into savings & investment does not count as support she spent on herself. Note that a fiancé is not  closely related so there is the requirement that she live with you all year.

If no one person (or married couple) provides 50% of the support (for example her family are also sending support), then a "multiple support agreement” (IRS Form 2120) can be used, to allow you to claim the dependent. https://www.irs.gov/pub/irs-pdf/f2120.pdf

The IRS has a worksheet that can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf The support value of a home is the fair market rental value, divided by the number of occupants.