Click-to-Open Rate
Email MarketingAlso: CTOR · Click to Open Rate
Quick definition
Click-to-open rate (CTOR) measures the percentage of people who clicked a link in your email out of those who opened it. Calculated as unique clicks divided by unique opens, multiplied by 100. CTOR isolates how well your email content performs once the subject line has done its job.
Ten to fifteen percent is a reasonable signal of content doing its job with an engaged audience. Below eight percent consistently suggests the offer, copy or design is not matching what the subject line promised.
How it varies across Australia
A CTOR above ten percent is generally a sign the content is landing with the audience that opened. Strong campaigns in well-maintained lists sit noticeably higher. Weak content or misaligned offers against a warmed audience often sit well below that line. CTOR is more stable than click-through rate across list size changes, which makes it a better trend indicator.
See email marketing benchmarks across Australian industries →What it actually means
Think of an email as a two-stage pitch. The subject line and preview text get someone to open. The body copy, design and offer get them to click. Click-through rate (CTR) blends both stages into one number. Click-to-open rate (CTOR) isolates the second stage entirely.
If your CTOR is strong and your CTR is weak, your email content is doing its job but fewer people are seeing it. Fix the subject line. If your CTOR is weak despite a healthy open rate, the email itself is the problem. The subject line made a promise the body didn't keep.
CTOR is the diagnostic tool CTR isn't. It removes list size and deliverability from the equation and asks a cleaner question: of the people who gave you their attention, how many acted on it?
There is one caveat worth knowing. Apple Mail Privacy Protection and other open-tracking workarounds inflate unique open counts by registering phantom opens. Inflated opens push CTOR down artificially. That doesn't make CTOR useless, but it does mean you should track the trend over time rather than treating any single number as absolute truth.
Click-through rate tells you how many people clicked. CTOR tells you whether the email was worth opening.
How to calculate it
CTOR = Unique clicks ÷ Unique opens × 100
Worked example. You send a campaign to 10,000 subscribers. 2,400 unique opens are recorded. Of those 2,400 openers, 312 click through to your offer. CTOR = 312 ÷ 2,400 × 100 = 13.0%. The subject line got 24% to open. The content then converted 13% of that engaged group.
The Australian context
Australian email marketers operate under the Spam Act 2003, which requires express or inferred consent before sending commercial messages. This means well-managed Australian lists tend to have a higher share of genuinely opted-in subscribers than comparable US lists, which can push CTOR up relative to global averages. If your CTOR is dragging despite good consent hygiene, the more likely culprits are content-offer mismatch or list segments that have aged without re-engagement.
ACMA enforces the unsubscribe requirements that keep Australian lists relatively clean by default. Businesses that honour those requirements see more meaningful CTOR signals because the openers in the denominator are likelier to be real people who chose to be there.
Where people get this wrong
Related terms
Common questions
What is a good click-to-open rate?
Ten to fifteen percent is a reasonable signal that content is resonating with the audience that opened. Below eight percent consistently points to a content or offer problem. Above twenty percent on a well-sized list usually indicates strong segmentation and content relevance. Context matters: promotional emails, newsletters and transactional messages all have different natural ranges.
How is CTOR different from click-through rate?
Click-through rate divides clicks by total emails delivered, blending list size, deliverability and content quality into one number. CTOR divides clicks only by the people who opened, isolating how well the content performed with an engaged audience. CTOR is the better diagnostic tool for content decisions.
Has Apple Mail Privacy Protection broken CTOR?
It has made it noisier. Apple's feature pre-loads email pixels, registering opens from users who may never have seen the email. This inflates the denominator and depresses CTOR. It hasn't made the metric useless, but it means a single-point CTOR reading is less reliable than a trend line over several sends.
How do I improve a low CTOR?
Start with the offer: does the email body deliver on what the subject line promised? Then look at the call-to-action placement and clarity. If both are solid, check whether the segment receiving the email is actually the right audience for the content. A low CTOR is almost always a content-audience mismatch problem before it's a design problem.
Keep exploring
About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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