Calculating your open rate is straightforward once you know the Email Open Rate formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Email Open Rate Calculator.
What is Email Open Rate?
The Email Open Rate calculation tells you your open rate from a few simple inputs. The figure you are solving for here is the open rate, expressed in percent.
The Email Open Rate formula
The core formula is:
Open rate = Unique opens ÷ Emails delivered × 100Here is what each input means:
- Unique opens — a number. Example: 250.
- Emails delivered — a number. Example: 1,000.
How to calculate it step by step
- Write down the unique opens (for example, 250).
- Write down the emails delivered (for example, 1,000).
- Apply the formula above to get your open rate.
- Double-check the result with the Email Open Rate Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Unique opens | 250 |
| Emails delivered | 1,000 |
| Open rate | 25.00% |
With unique opens of 250 and emails delivered of 1,000, the open rate works out to 25.00%.
Example 2
With unique opens of 500 and emails delivered of 1,000, the open rate works out to 50.00%.
| Result | Value |
|---|---|
| Open rate | 50.00% |
Example 3
With unique opens of 130 and emails delivered of 1,000, the open rate works out to 13.00%.
| Result | Value |
|---|---|
| Open rate | 13.00% |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Email Open Rate Calculator does it instantly, for free, with the formula and a worked example built in.
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