無料のオンライン email open rate calculator. 計算 open rate, opens needed, or emails delivered for your email marketing campaigns. Compare against industry benchmarks. 純クライアントサイド, 広告なし.
Email Open Rate is one of the most important metrics in email marketing. It measures the percentage of delivered emails that were opened by recipients. A healthy open rate indicates strong subject lines, good sender reputation, and relevant content. This calculator helps you quickly compute open rate, required opens, or required delivery volume — whichever two values you know. All calculations happen entirely in your browser — no data is ever sent to a server.
Email Open Rate is the percentage of delivered emails that were opened by recipients. The formula is: Open Rate = (Opens / Emails Delivered) × 100. For example, if you sent 5,000 emails and 1,250 were opened, your open rate is 25%. 注: open rate is calculated against emails delivered, not total sent (bounces are excluded).
A good open rate varies by industry. 平均 across all industries is 21–25%. Retail/e-commerce typically sees 15–20%, SaaS/tech 20–25%, finance/banking 25–30%, healthcare 23–28%, and non-profits often achieve 25–35%. Your own historical performance is the best benchmark.
To improve open rates: write compelling subject lines (keep under 50 characters), personalize with recipient names, segment your audience for relevance, optimize send times, maintain a clean email list, use a recognizable sender name, avoid spam trigger words, and A/B test subject lines regularly.
Open rate measures how many recipients opened your email. Click-through rate (CTR) measures how many of those openers clicked a link inside the email. Open rate reflects subject line and sender reputation effectiveness, while CTR reflects content and call-to-action quality.