How can i turn off round up in qbo? And if this is not possible, is it possible in qb desktop?

Glad to have you here in the Community, @raalduraiee.

At this time, the option to turn off rounding off of the sales and expense transactions amount isn't available in both QuickBooks Online (QBO) and QuickBooks Desktop (QBDT).

I can see how beneficial it is for you and your business to turn off the round-up option in both QBO and QBDT. However, QuickBooks is designed to round off the amounts automatically.

For now, you can visit our blog site so you'll be able to get the latest news about QuickBooks and what our Product Care Team is working on. 

Keep in touch if you need any more assistance with this, or there's something else I can do for you. I've got your back.