How Long to Leave a Face Mask On (By Mask Type)Leaving a face mask on too long can irritate or over-dry skin. Clay masks: 10–15 minutes. Sheet masks: 15–20 minutes. Overnight masks: sleep in them. Here's the complete guide.Frequently asked questionsIs TimerRush free?Completely free — no account required.Where can I try the timers mentioned in this guide?All timers are at timerrush.com. Bookmark /t/25m or /t/5m for quick one-click access.