Does anyone have a good profit calculator for the full supply chain?

I’m very new to this and I’m thinking of manufacturing my first product.

Cogs will be 4 dollars for qty 500, I’m thinking it can retail for 25 dollars.

I need to get the shipment from factory and do a repack, since I’m not comfortable having my factory ship straight to Amazon warehouse (maybe that’s not a valid concern). I used a basic free spreadsheet I found and after running the numbers I end up with only 1,5 dollars of profit. To me that’s insane! From 4 dollars cogs all the way to 23,5 dollars. Is that realistic or is something off? I know that’s a lot of questions in 1 post, but having a calculator spreadsheet that the community here likes would also be a big help.

Cheers!