What is the earliest time it’s considered socially acceptable to call a co-worker to discuss business?

The acceptable time to call a co-worker for business purposes can vary depending on cultural norms, the nature of your work, and your co-worker's personal preferences. However, a general guideline is to avoid calling outside of typical business hours unless it's an urgent matter.

In many cultures, the standard business hours are considered to be from 9 AM to 5 PM, Monday through Friday. Calling during these hours is usually safe and acceptable. Before 9 AM and after 5 PM, it's advisable to avoid non-urgent business calls, as people may be with their families, engaged in personal activities, or simply winding down for the day.

If you need to discuss business matters outside of regular hours, it's often better to send an email or use other asynchronous communication methods. This allows the recipient to respond at a time that is convenient for them.

It's essential to be mindful of your co-workers' preferences and the cultural norms within your organization to ensure that your communication is respectful and considerate of their time. If you're unsure, you can always ask your co-worker about their preferred communication times or check any company policies that might be in place.