Since the current time is 3:47 PM EDT today, the time until 12:00 PM (noon) today has already passed because noon is earlier in the day. If you mean how many hours until 12:00 AM (midnight) tonight, that would be 8 hours and 13 minutes from now. If you meant how many hours until 12:00 PM tomorrow, that would be approximately 20 hours and 13 minutes from 3:47 PM today. To clarify:

• Hours until 12:00 PM today: 0 (already past)
• Hours until 12:00 AM midnight tonight: about 8 hours 13 minutes
• Hours until 12:00 PM tomorrow: about 20 hours 13 minutes

This is based on the standard 12-hour clock definitions and current time