Attic Pine Oriented Strand Board (Common: 5/8 in. x 2 ft. x 4 ft.; Actual: 0.594 in. x 23.75 in. x 47.75 in.)

OMAR, The community has rallied to answer your question, so we grouped the first three responses because they are going to be helpful to you and others DIYers: Check the distance between the centers of the joists. Common spacings used include, but are not limited to: 12, 16 and 24 inches. If your centers are at 24 inches or 12 inches, then cutting in half would work. A 16 inch center covers a third of the sheet. Note: be careful when cutting, as sloppy joist layout or warped joists may make the spacing non-uniform. Measure several joists to determine the average spacing. You may have to modify your cuts as you go if the layout is non-uniform. I usually lay out several panels across the joists before cutting or attaching to be sure the spacing will work out. Often times a non-uniform section is limited to a specific area requiring special care during cutting and fitting. Yes. These install the long way, face grain perpendicular across 3 or 4 joists depending on your spacing. So if you wanted to stagger, start the next panel over by one joist. For 16” on center joists cut the board 32” or 16”

yes, as this is exactly what I used it for and there's no give and it's study with 16 off center studs

Check your local building code. For living areas you typically need thicker underlayment that supports a higher live load

yes, but why use something this thick? If yiur floor is that bad, I would even it out with thinset to make it level first

I didn't need the extra support with 16" off center studs, unless you're over 200lbs or plan on putting a lot of weight up there. it was fine to walk on with no movement or give

Check your local building code. Typically you will need a thicker underlayment in living areas.

Yes

4ft side.

very good & easy for home repair.

I used 2 inch screws and it worked great.