There are a few different types of sinus infections and one is contagious and the other one is not.
But if you're unsure which sinus infection you do have you should stay home from work or other public places until the sinus infection clears up.
If you have a viral sinus infection then the viral sinus infection can be contagious for a few days even before you actually feel the sinus infection coming on and the sinus infection can also remain contagious for 3 to 6 days afterwards.
Sometimes it may be contagious for as long as a week but that's rare.
Most sinus infections whether bacterial or viral clear up within 10 to 14 days but more severe sinus infections may last 4 to 12 weeks.
If you have a bacterial sinus infection then that cannot be spread and nobody else can catch the bacterial sinus infection from you but they can catch a viral sinus infection from you.
If you have a fever and a viral sinus infection then stay home from work or other public places until the fever is as least gone.
Sinus infections are contagious and can be spread from person to person easily so you could give a sinus infection to your coworkers especially if you happen to work close together as in an office.
If you do go to work with a sinus infection you may not be as productive anyway so it would be best to stay home until you recover from the sinus infection.
If you have a fever with the sinus infection you should stay home because when you have a fever with the sinus infection you're almost always still contagious.
Do yourself and your coworkers a favor and take a few days off from work until you're feeling better from the sinus infection.
Sometimes you can be contagious for a few days even before you got the sinus infection and then when you get the sinus infection you can be contagious for a few more days afterwards to as long as a week.