What Is Email Open Rate and How Do You Improve It?

Email open rate is the percentage of your subscribers who open a given email campaign. If you send an email to 500 people and 100 of them open it, your open rate is 20 per cent. It is the first metric most email marketers look at because it tells you whether your subject line and sender name are compelling enough to earn attention in a crowded inbox.

Open rate is a useful indicator but not the full picture. It is tracked by loading a tiny invisible image in the email, which means it can be affected by email clients that block images or pre-load them automatically — Apple Mail, for example, began pre-loading images in 2021, which inflated open rates for many senders. Despite this limitation, open rate trends over time remain a valuable signal of list health and subject line effectiveness.

What Is a Good Open Rate?

Average open rates vary significantly by industry. Across all sectors, a rate of 20 to 30 per cent is generally considered healthy for a permission-based list. Some niches — particularly professional services, nonprofits, and membership organisations — routinely see higher rates. Retail and e-commerce tend to sit at the lower end. The most useful benchmark is your own historical average: focus on improving your rate over time rather than chasing an industry number.

If your open rate is below 15 per cent, it is worth investigating why. Common causes include a subject line that fails to create curiosity or convey value, a sender name that subscribers do not recognise, a list that has grown stale with many inactive addresses, or emails landing in spam. Each of these has a different fix.

Subject Lines and Preview Text

Your subject line is the single biggest lever for open rate. It appears in the inbox alongside your sender name and, on most email clients, a short preview snippet of the email body. Together, these three elements are all a subscriber sees before deciding whether to open or ignore your message.

Effective subject lines tend to be specific, short, and either curiosity-driven or benefit-led. "3 things holding your website back" outperforms "Our latest newsletter" every time. Avoid all-caps, excessive punctuation, and words commonly associated with spam. Test different approaches — most platforms allow A/B testing where half your list receives one subject line and the other half receives an alternative, and you can see which performs better.

List Hygiene and Sender Reputation

A list full of inactive addresses drags your open rate down and damages your sender reputation, making it more likely your emails land in spam for everyone. Most platforms show you which subscribers have not opened an email in six months or more. Periodically send a re-engagement campaign to these contacts asking whether they still want to hear from you. Those who do not respond should be removed.

Your sender reputation is also affected by bounce rates and spam complaints. Keep bounces low by removing hard bounces immediately, and make it easy for people to unsubscribe — a difficult unsubscribe process leads to spam complaints, which hurt your deliverability far more than a clean opt-out would.