Unlimited, on every plan, and it is one of Xero’s genuine structural advantages over competitors that bill per seat. You can give access to your bookkeeper, your business partner, an office manager and us without any of it changing your subscription. That changes how you should think about setup: instead of sharing a login to save money — which destroys your audit trail and is a security problem — give everyone their own account with permissions matched to their role. Xero’s permission levels are reasonably granular, so an employee raising sales invoices need not see payroll or your bank balance. The one thing worth being disciplined about is removing access when someone leaves, which is exactly the sort of thing nobody remembers to do.