[GTM glossary](/glossary.md) Open rate

Sales Development & Prospecting

# Open rate

In short

Open rate is the percentage of delivered emails that registered as opened. It is calculated as unique opens divided by emails delivered, multiplied by 100.

Opens are usually detected with a tiny tracking image. Because some mail apps preload images or block them, open rate is a directional signal, not an exact count of people who read your message.

## How open rate is calculated

Say you deliver 500 emails and 150 register an open. Your open rate is 30 percent. This is an example calculation, not a benchmark.

* **Delivered, not sent:** Use delivered emails so bounces do not distort the rate.
* **Unique vs. total:** Unique opens count each recipient once; total opens count repeats.

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## Why open rate is less reliable now

Some email clients prefetch images automatically, which can record an open the person never made. Others block images, hiding real opens. Treat the number as noisy.

* **Inflated:** Automatic image loading counts opens with no human action.
* **Deflated:** Blocked images hide real opens.
* **Hard to compare:** Different tools count opens differently.

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## What open rate can tell you

Despite the noise, comparisons inside the same audience and tool are useful.

* **Subject line tests:** Compare two subject lines sent to similar lists.
* **Deliverability warning:** A sudden drop across all campaigns can point to inbox placement problems.
* **Trend, not target:** Watch direction over weeks rather than a single number.

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## Better metrics to pair with it

* **Reply rate:** Shows that a real person responded.
* **Positive reply rate:** Shows interest, not just activity.
* **Meetings booked:** The outcome that matters.

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## Common mistakes

* **Optimizing for opens only:** A clever subject line that misleads lowers trust and replies.
* **Comparing to outside averages:** Audience and list quality vary too much.
* **Ignoring list quality:** Bad data lowers opens before copy matters.

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## Open rate FAQs

**What is open rate in email?**

Open rate is the percentage of delivered emails that registered as opened, calculated as unique opens divided by delivered emails times 100. It is detected with a tracking pixel, so it is an approximate engagement signal rather than an exact reading count.

**How do you calculate email open rate?**

Divide the number of unique opens by the number of delivered emails, then multiply by 100. For example, 150 unique opens from 500 delivered emails gives a 30 percent open rate. Use delivered emails, not sent, to exclude bounces.

**Is open rate still a reliable metric?**

Less than before. Some email apps preload images, which can count opens that never happened, and others block images, hiding real opens. Use open rate for relative comparisons and rely on replies and meetings for decisions.

**How can I improve my email open rate?**

Send to accurate, relevant lists, use clear honest subject lines, keep sender names recognizable, protect deliverability, and test timing. Make changes one at a time, and judge success by replies and meetings, not opens alone.

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## More related phrases

* [Connect rate](/glossary/connect-rate.md)
* [Email bounce rate](/glossary/email-bounce-rate.md)
* [Email personalization](/glossary/email-personalization.md)

## Similar phrases

* [Click-through rate (CTR)](/glossary/click-through-rate.md)  
Click-through rate (CTR) is the percentage of people who click a link, ad, or email after seeing it, calculated as clicks divided by impressions or sends.
* [Reply rate](/glossary/reply-rate.md)  
Reply rate is the percentage of delivered outreach messages that get any response, used to judge how well your targeting, copy, and deliverability work.
* [Email deliverability](/glossary/email-deliverability.md)  
Email deliverability is your ability to get emails into recipients’ inboxes instead of spam or being rejected, shaped by reputation, authentication, and content.
* [Positive reply rate](/glossary/positive-reply-rate.md)  
Positive reply rate is the share of outbound messages that get an interested response, such as a meeting request, rather than just any reply.
* [Bounce rate](/glossary/bounce-rate.md)  
Bounce rate is the percentage of sent emails that are rejected by the recipient's mail server and never reach an inbox, split into hard and soft bounces.