I've filled out everything for my dependent (inc. I've paid for >50% of their expenses), but TurboTax tells me my filing status is "Single" since I didn't pay > 50%? Why?

[japostoles]

Additionally, they are under $4400, lived with me the full year.  

[JohnB5677]

I suggest you go back through the dependent listings.

Go to:

1. My Info
2. Select each of your dependents.
3. Go back through the interviews.
4. The wording for support is different.
   1. Did My Child pay for more than half of their living expenses and other support?  (We know My Child's a kid, but we have to ask.)
   2. Answer NO!

[japostoles]

What I'm seeing is this question:

"Did you pay for more than half of TheirName's living expenses in 2022?"

To which I answer "YES", then:

"Good news! TheirName qualifies as your dependent."

Then on the next page:

"

Your filing status: SINGLE

The IRS requires you to file this way if you weren't legally married as of Dec 31, 2022.

We checked, and even though you have a dependent, you don't qualify as Head of Household because you didn't pay for more than 50% of household expenses.

"

[JamesG1]

To qualify for Head of Household filing status, you must pay more than half the cost to keep up a home in 2022.

You may qualify for Head of Household filing status if you:

• Were unmarried as of December 31, 2022 and
• Paid more than half the cost of keeping up your home during the tax year (rent, mortgage, utilities, etc.), and
• Supported a qualifying person.

If you were legally married as of December 31, 2022 and a child lives with you, you may qualify for Head of Household filing status if:

• You will not be filing jointly with your spouse,
• Your spouse did not live in your home during the last six months of the year,
• Your home was your child's, stepchild's, or foster child's main home for more than half the year, 
• You paid more than half the costs of keeping up your home during the tax year,
• You meet the qualifications to claim the child as your dependent, even if the other (noncustodial) parent is actually claiming the child as a dependent on their return.

TurboTax software will ask you simple questions and give you the filing status, credits and deductions that you are eligible for based upon your answers.

See also this TurboTax Help.

@japostoles