Email marketing metrics: Open Rate, CTR, CTOR and others

You’ve sent out an email campaign; the report shows a few figures and percentages, and you’re wondering which of them actually mean anything. Open Rate, CTR, CTOR, conversion rate… Each of these metrics describes a different point of contact between the recipient and the message.

Only when read and analysed together do they reveal what worked and what needs improving. In this article, we explain how to calculate the most important metrics in email marketing and how to interpret the results without jumping to conclusions.

Open Rate – what is it and what does it tell us about the campaign?

The Open Rate is the percentage of recipients who opened the message out of all those to whom the email was delivered. It is the ratio of opens to delivered messages, always expressed as a percentage.

This metric primarily assesses the effectiveness of the subject line and preheader. Recipients decide whether to open an email within a few seconds, based on the sender’s name and the first line of text they see. Put simply, a high Open Rate indicates that the brand is recognisable and that its messages are considered credible and thematically appealing.

The average open rate in email marketing usually ranges from 15 to 25 per cent. A result above 25 per cent is considered very good, whilst the normal open rate for a regular newsletter hovers around the lower end of this range. But remember that the figures we provide are merely indicative. When evaluating results, you should take into account the specific nature of the industry and the size of the mailing list, as results can vary significantly.

Importantly, very high results also require verification. An open rate of 50–60 per cent can occur with small, highly engaged mailing lists, but more often it indicates something else: the automatic loading of a tracking pixel by privacy protection mechanisms in email clients. Opens are then counted, even though no one has actually read the message. That is why, in your analysis, it is worth comparing the open rate with click-through rates.

How to calculate the open rate? Formula and exampld

To calculate the open rate, divide the number of emails opened by the number of emails delivered, and multiply the result by 100%.

The formula is as follows: (emails opened / emails delivered) × 100%

A real-world example from an e-commerce store: the campaign was sent to a list of 19,600 addresses, of which 19,400 emails were delivered. 3,880 of these were opened. The Open Rate is therefore 20%.

Pay attention to the denominator. You’re calculating based on messages delivered, not sent. If you were to use the number of messages sent, the result would be underestimated by the number of bounces, and with a poorly maintained database, the difference can be significant.

CTR, or click-through rate in email marketing

CTR is the percentage ratio of the number of clicks on links to the number of messages delivered. The abbreviation stands for ‘click-through rate’.

CTR works on a simple principle. The system counts every click on a link included in the message and compares this to the number of people who received the email. Calculating CTR boils down to a simple formula: (clicks / messages delivered) × 100%.

In reports, you’ll come across two variants of this metric. The first takes all clicks into account, whilst the second considers only unique recipients. To compare campaigns with one another, choose one variant and stick to it consistently.

The CTR in email marketing is significantly lower than the open rate and usually ranges from 2 to 5 per cent. A high CTR indicates that the content and offer matched what the subject line promised. A low click-through rate alongside good open rates signals a mismatch between the preview and the message’s content, or a problem with the CTA itself.

CTR outside of email

The same click-through rate metric is used in search engines and advertising campaigns, except that impressions are used as the reference point rather than delivered messages.

In SEO, the click-through rate (CTR) shows what percentage of people who see your link in search results actually click on it. Google provides this data for individual keywords in Search Console. A high CTR for organic results means that the page title and meta description attract users’ attention more effectively than competing links. Improving the CTR in search engines usually translates into organic traffic without the need to achieve higher rankings.

In the case of adverts, the mechanism is identical. Ads on Google Ads, social media or display networks are billed based on the number of impressions and clicks, and CTR is used to assess which ad creatives are performing well. In digital marketing, a low CTR with a high number of impressions usually indicates that the message is poorly tailored to the target audience or that the creative is weak.

CTOR – a metric that combines opens with clicks

CTOR (click-to-open rate) is the percentage of clicks calculated not from all delivered messages, but exclusively from those who opened the message.

The formula is (clicks / opens) × 100%. This means the metric disregards the influence of the subject line and preheader, and shows only what happened within the body of the email.

This makes CTOR the best measure of the quality of the content itself. If the Open Rate has fallen but the CTOR has remained stable, the problem lies with the subject line, not the offer. The opposite situation means that you captured attention with the teaser, but the content did not meet expectations.

Typical results range from 10 to 20 per cent. A high CTOR indicates that the content is better aligned with users’ preferences: the email layout is clear, the CTAs are visible, and the customer is genuinely interested in the offer.

Other metrics worth analysing

Open Rate and CTR describe the start of the journey, but what happens next determines the campaign’s effectiveness. The table below summarises the metrics that are worth analysing together.

The conversion rate is the most practical metric, as it links email sends to revenue. A campaign with average open rates but high sales is simply more effective than one with a record-breaking open rate and an empty shopping cart.

The bounce rate and unsubscribe rate, in turn, act as a warning system. A high bounce rate damages the sender’s reputation and reduces the deliverability of subsequent mailings. A rising number of unsubscribes usually indicates that mailings are too frequent or that the content does not match what the recipient signed up for.

See also: KPI – what is it? What are Key Performance Indicators? >>>

How to improve the open rate and CTR?

Improving the CTR and open rate rarely results from a single change. It is more effective to make several adjustments one at a time and measure them separately.

1. Segmenting your mailing list. Tailoring content to recipients’ interests yields a higher open rate than mass mailings. Segment your list according to purchase history, activity or recipients’ stated preferences, and tailor your message to each target group individually.
2. Subject line testing. Regular A/B tests reveal which phrasing grabs attention and which is ignored. Test one element at a time: subject line length, personalisation by name, or the use of emojis. Marketing automation platforms such as ExpertSender allow you to automate these tests and send the winning variant to the rest of the mailing list.
3. Send time. The time of day and day of the week have a real impact on the likelihood of an email being opened. Optimising the send time based on subscribers’ previous activity usually yields better results than sticking to a rigid schedule.
4. Prominent CTAs and mobile-friendly design. Most emails are opened on mobile devices, so the button must be large and positioned high up on the screen. The less scrolling required before the first CTA, the greater the chance of a click.
5. List hygiene. Removing inactive addresses improves both deliverability and percentage metrics, as the denominator no longer includes inactive contacts. This is the element of the strategy that is easiest to overlook, yet it affects all email marketing campaigns simultaneously.

Metrics alone won’t improve your webshop’s situation. It’s worth defining and measuring key performance indicators, but a change in sales will only become apparent when segmentation, testing and automated mailings operate within a single system, and reports are clear and practical.

Book a free consultation and find out how to boost sales through effective marketing automation.

Frequently Asked Questions (FAQ)

What is click-through rate?

Click-through rate is the ratio of the number of clicks to the number of people who saw a message or advert. It works on a simple principle – the system counts every click on a link and compares it with the number of messages delivered or impressions. The result is expressed as a percentage and is treated as a measure of interest in the content.

What does the abbreviation CTR stand for?

CTR stands for ‘click-through rate’. It refers to the percentage of clicks amongst all recipients who had the opportunity to see the link. The same abbreviation is used in email marketing, search results and advertising campaigns.

How can you increase your CTR?

The quickest way is to tailor content to a specific segment of your mailing list rather than sending a single message to everyone. Add to this a single clear call-to-action (CTA) placed prominently in the message and regular A/B testing.

For adverts and organic search results, improving the CTR primarily requires better alignment of the headline with the intent behind the keywords. Also, remember to regularly clean your mailing list of inactive contacts.

What constitutes a good CTR?

In email marketing, a CTR of between 2 and 5 per cent is generally considered good, although much depends on the specifics of the industry and the type of campaign.

Campaigns targeting narrow, active segments can perform significantly better than mass newsletters. For business owners, it is most useful to compare their own campaigns with one another, rather than against general averages.

What exactly does the open rate measure?

The open rate measures the percentage of recipients who opened the message out of those to whom it was delivered. It primarily assesses the effectiveness of the subject line, preheader and sender recognition.

It says nothing about whether the content inside actually interested the recipients.

Is an open rate of 20–21 per cent a good result?

Yes, 20–21 per cent falls within the typical range for email marketing and is a decent result.

Only when it exceeds 25 per cent do we consider it a very good result. For your business, the trend is more important than the figure itself: a stable or rising open rate with a healthy subscriber base means more than a one-off spike.