If you send 100 emails and 20 people open them, your open rate is 20%. This metric tells you how well your subject lines, sender name, and timing are working. A subject line like "50% off for 1 hour only!" creates urgency and drives higher opens.
Good open rates depend on your industry — average is around 20-25%. Key factors include a recognizable sender name, compelling subject lines (keep them under 50 characters for mobile), and optimal send timing. Most people check email on mobile, so short, punchy subject lines perform best. If your open rate is low, experiment with different subject lines and sending times.