Email Open Rate Calculator: Opens as a Share of Delivered Emails
Work out your email open rate from opens and delivered emails — the classic engagement metric for newsletters and campaigns, with the unopened share shown alongside.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Open rate | Not opened |
|---|---|---|
| 420 of 2,000 (21%) | 21.00% | 79.00% |
| 300 of 1,000 (30%) | 30.00% | 70.00% |
| 1,200 of 8,000 (15%) | 15.00% | 85.00% |
| 550 of 1,000 (55%, small engaged list) | 55.00% | 45.00% |
How This Calculator Works
Enter the number of opens and the number of delivered emails (sent minus bounces). The calculator divides one by the other and multiplies by 100 to give the open rate, with the unopened share next to it. Always use delivered, not sent, as the base for an accurate figure.
The Formula
Part as a Percentage of a Whole
Part is the portion, Whole is the total it belongs to
Worked Example
420 opens from 2,000 delivered emails is a 21% open rate, with 79% not opened. Average open rates vary by industry but commonly land in the 15%–30% range. Two important caveats: always calculate on delivered (not sent) emails so bounces don't distort the rate, and know that open tracking has become unreliable — Apple's Mail Privacy Protection pre-loads tracking pixels, automatically counting 'opens' that may not reflect a real read, which inflates open rates for audiences with many Apple Mail users.
Key Insight
Open rate used to be the headline email metric, but privacy changes have made it far less trustworthy, so treat it as a directional signal rather than gospel. Apple's Mail Privacy Protection (and similar features) pre-fetch the tracking pixel, registering opens that didn't happen — which can inflate open rates substantially and break historical comparisons. The practical response is to lean on metrics that survive these changes: click-through rate and clicks-to-delivered measure actual engagement, conversions tie email to revenue, and list health (unsubscribes, spam complaints, bounce rate) signals deliverability. If you do track opens, use them for relative trends within the same audience and tooling, segment heavily, and never optimize subject lines on open rate alone now that the number is polluted. The fundamentals still matter most: a clean, engaged list, a recognizable sender, relevant content, and good send timing drive both real opens and the clicks that actually count.
Frequently Asked Questions
How is email open rate calculated?
Divide opens by delivered emails, then multiply by 100. 420 opens from 2,000 delivered is a 21% open rate, with 79% not opened. Use delivered (sent minus bounces), not total sent, as the base.
Should I use sent or delivered as the base?
Delivered. Bounced emails were never received, so including them in the base understates your true open rate. Most email platforms report on delivered by default — calculating on delivered gives an accurate picture of how your reachable audience engaged.
What's a good email open rate?
It varies by industry, commonly 15%–30%, but benchmarks have become less meaningful since privacy features distort open tracking. Compare against your own historical rates within the same audience and tools rather than chasing a universal number.
Why is open rate unreliable now?
Apple's Mail Privacy Protection and similar features pre-load email tracking pixels, registering 'opens' that may not reflect a real read. This inflates open rates for audiences with many Apple Mail users and breaks comparisons to older data, so open rate is now a directional signal, not a precise one.
What should I track instead?
Metrics that survive privacy changes: click-through rate and clicks-to-delivered (actual engagement), conversions (email's link to revenue), and list-health signals like unsubscribes, spam complaints, and bounce rate. These measure real interest and deliverability better than a polluted open rate.
Related Calculators
Methodology & Review
The open rate is opens divided by delivered emails, multiplied by 100. The complement is the share not opened. It uses delivered (not sent) as the base; open tracking relies on a pixel load, which privacy features like Apple Mail Privacy Protection can inflate or distort.
Written by Ugo Candido · Last updated May 22, 2026.