Do I lose money from freelance work when I declare it for my taxes?

If I earn 45k this year doing freelance, do i lose $7000?

I earned 45k from what I got paid but supplies add up too so technically only made about 31k so if they take near 10k away from me I'll have made near nothing for hours of labor.
Update: I didn't actually earn this yet still just a rough calculation.

I work selling custom furniture and artwork
12 answers 12