# Email Click-to-Open Rate Calculator

> Calculate click-to-open rate (unique clicks ÷ unique opens), open rate and click rate (both ÷ delivered) for an email campaign.

Category: Marketing analytics · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/email-click-to-open-rate-calculator

Click-to-open rate shows how many people who opened an email went on to click: unique clicks divided by unique opens.

Also called: CTOR calculator, Email open rate calculator.

## Inputs
- Emails delivered (default 10000)
- Unique opens (default 2500)
- Unique clicks (default 300)

## Results
- Click-to-open rate
- Open rate (of delivered)
- Click rate (of delivered)

## Formula

```
CTOR = Unique clicks ÷ Unique opens × 100;  Open rate = Unique opens ÷ Delivered × 100;  Click rate = Unique clicks ÷ Delivered × 100
```

Where:
- Unique opens: recipients who opened (CTOR denominator)
- Delivered: emails that did not bounce (open- and click-rate denominator)

## Worked example
1. CTOR = 300 ÷ 2,500 × 100 = 12%.
2. Open rate = 2,500 ÷ 10,000 × 100 = 25%.
3. Click rate = 300 ÷ 10,000 × 100 = 3%.

**Result:** 300 clickers among 2,500 openers is a 12% click-to-open rate; 3% of all delivered recipients clicked.

## What the result means

Open rate reflects the subject line and sender; CTOR reflects the content once opened. A high open rate with a low CTOR suggests the email did not deliver on its subject line.

## Assumptions and limits
- Opens and clicks are unique (each recipient counted once).
- Privacy features such as Apple Mail Privacy Protection record opens automatically, inflating opens and lowering CTOR. Click-based metrics are more reliable.

## Questions

### Why can someone click without an open being recorded?

If images are blocked the open pixel never loads. Most email platforms count a click as an open, which is why clicks cannot exceed opens here.

## Related calculators
- [Email Bounce Rate Calculator](https://calculators.geekmidst.com/calculators/email-bounce-rate-calculator)
- [Email Unsubscribe Rate Calculator](https://calculators.geekmidst.com/calculators/email-unsubscribe-rate-calculator)
- [Click-Through Rate Calculator](https://calculators.geekmidst.com/calculators/click-through-rate-calculator)
- [Email Subscriber Growth Calculator](https://calculators.geekmidst.com/calculators/email-subscriber-growth-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/email-click-to-open-rate-calculator