Email Click To Open Rate (CTOR) Calculator

For email marketers, lifecycle teams, and analysts. Compute your Click-To-Open Rate—a key engagement metric—instantly. All calculations run offline in your browser; your data never leaves your device.

Estimates only. Verify with your analytics data.

Input Your Numbers

Unique Opens (count)

Total number of recipients who opened the email (unique opens).

Unique Clicks (count)

Total number of unique recipients who clicked any link in the email.

Decimal places

Results

Click-To-Open Rate (CTOR)

0.00%

Unique Clicks ÷ Unique Opens × 100

Unique Opens: 0

Unique Clicks: 0

Click‑to‑Open Ratio: 0.0000

Assumptions Used

CTOR = (Unique Clicks / Unique Opens) × 100
Unique opens and clicks are for the same email campaign and time period.

Why Email CTOR Matters

Click‑To‑Open Rate (CTOR) isolates the engagement of your email’s content from its deliverability. While open rate measures how well your subject line and sender name performed, CTOR tells you whether the email body resonated with those who opened it. A low CTOR suggests your content, offer, or layout didn’t compel action—even though recipients opened the email. This metric helps lifecycle and retention teams optimize content, calls‑to‑action, and design for higher in‑email engagement.

Understanding Each Input

Input	What it represents	Where to find it	Common pitfall
Unique Opens	Number of individual recipients who opened your email at least once. Deduplicated; multiple opens by the same person count as one.	Email platform reports (Mailchimp, Klaviyo, HubSpot, SendGrid). Usually labelled “Unique Opens” or “Recipients who opened”.	Confusing “total opens” (includes re‑opens) with “unique opens”. Use unique opens for CTOR.
Unique Clicks	Number of individual recipients who clicked any link in the email at least once. Deduplicated; multiple clicks by the same person count as one.	Same email platform reports, labelled “Unique Clicks” or “Recipients who clicked”. Not “total clicks”.	Using “total clicks” inflates the rate. Ensure the time window matches the opens metric exactly.

Step‑by‑Step Guide

Pull the campaign report from your email platform.
Locate the Unique Opens and Unique Clicks figures for the same campaign and same time period.
Enter the numbers into the calculator above.
Review the CTOR percentage and the intermediate ratio.
Use the “What‑If” helper below to model how changes in opens or clicks affect CTOR.

Realistic Examples

Example 1: Newsletter

Inputs: Unique Opens = 10,000; Unique Clicks = 850.

Calculation: 850 ÷ 10,000 = 0.085; 0.085 × 100 = 8.5% CTOR.

Interpretation: 8.5% of opened emails resulted in a click. Benchmark varies by industry; 8‑12% is typical for broad newsletters.

Example 2: Promotional Campaign

Inputs: Unique Opens = 2,500; Unique Clicks = 600.

Calculation: 600 ÷ 2,500 = 0.24; 0.24 × 100 = 24.0% CTOR.

Interpretation: High CTOR indicates a highly relevant offer/CTA to the opened audience. Above 20% is strong for promotional emails.

Interpretation Guide

If CTOR is higher than expected

Your email content strongly resonates with the segment that opened.
Calls‑to‑action (CTAs) are clear and compelling.
Check if the sample size (opens) is sufficient (>200).

If CTOR is lower than expected

Content may not match the promise of the subject line.
CTAs might be hidden, unclear, or unappealing.
Design or layout could be broken on certain email clients.

What to double‑check before acting

Are unique clicks and opens from the same attribution window? Clicks tracked later than opens can undercount.
Did the email contain only one link? Multiple links can increase unique clicks but also indicate engagement fragmentation.
Is your audience segment consistent? A/B test variants should be compared separately.

Common Mistakes Checklist

Using “total opens” or “total clicks” instead of unique counts. Comparing CTOR across campaigns with vastly different open rates. Ignoring email client rendering issues that suppress clicks. Not segmenting by audience type (new vs. engaged subscribers).

What‑If: Target CTOR Helper

Given your current unique opens, how many additional unique clicks would you need to reach a target CTOR?

Current Unique Opens

Current CTOR (%)

Desired CTOR (%)

Required Lift

0 additional unique clicks

This is the extra unique clicks needed, assuming the same unique opens.

Frequently Asked Questions

How accurate is this calculator?

It performs exact arithmetic on the numbers you provide. Accuracy depends entirely on your input data’s correctness and the appropriateness of the CTOR formula for your context.

What’s a “good” CTOR?

Benchmarks vary by industry, email type, and audience. Newsletter CTOR often ranges 8‑15%; promotional emails 15‑25%. Track your own baseline over time rather than chasing generic benchmarks.

Why use unique clicks instead of total clicks?

Unique clicks measure how many people engaged. Total clicks include multiple clicks by the same person, which can inflate engagement perception. CTOR is a person‑based metric.

How does CTOR differ from Click‑Through Rate (CTR)?

CTR is (Clicks ÷ Delivered Emails). CTOR is (Clicks ÷ Opens). CTR measures overall campaign performance including deliverability; CTOR measures content performance among those who opened.

Can I compare CTOR across different email platforms?

Yes, but ensure each platform defines “unique opens” and “unique clicks” consistently. Some platforms may count opens/clicks differently (e.g., image‑loading vs. engagement pixels).

Formulas & Assumptions

CTOR = (Unique Clicks ÷ Unique Opens) × 100

If opens are zero, CTOR is undefined (treated as 0%).

Unique metrics are deduplicated at the recipient level.
All numbers are treated as non‑negative integers; decimals are truncated.
Rounding: final CTOR is rounded to the selected decimal places using standard rounding.
This tool does not apply any weighting, seasonality, or predictive adjustments.

Disclaimer: For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool does not replace professional marketing, analytics, or financial advice.

Sources & References

Basic email marketing metrics: Open Rate, Click‑Through Rate (CTR), Click‑To‑Open Rate (CTOR)
Email platform reporting conventions (Mailchimp, Klaviyo, HubSpot, SendGrid)
Engagement measurement: unique vs. total interactions

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Email Click To Open Rate CTOR Calculator

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