How we compile benchmarks

The rules behind every benchmark page: where the figures come from, how sources are graded, what we show from each publisher and how the pages stay current.

Updated Sep 24, 2026

The rules

Every figure comes from one named source, shown with its sample, data window and statistic.
We never average figures from different sources into one number.
Every figure is labelled with what it counts, and figures that count different things are shown in separate groups.
Dates are data dates: we show the period the data describes, not only when a report was published.
Older data stays visible but is marked. A figure whose data is more than 24 months old is labelled "older data" and is never used as the current reference.

How we grade sources

Grade	What it means	How we use it
A	Large sample, method and data window stated by the publisher	Shown; can be the at-a-glance figure for its definition
B	Sample or method only partly stated	Shown, with the missing details noted
C	Compiled from other sources, or undocumented	Not shown as a figure; may be named as further reading

What we record for every figure

Publisher and report

Who published the figure, and the report it appears in.

Edition and data window

The edition, and the period the data covers.

Sample

What was measured, in the publisher's own words (for example, 3.6 million campaigns from 181,000 accounts).

Statistic

Median, mean or average, or "not stated" when the publisher does not say.

Definition

What counts: for example, unique or total opens, campaigns or automated emails.

Segment

The industry, region or email type the figure describes.

Last checked

When we last opened the source and confirmed the figure.

What we show from each publisher

We follow each publisher's own terms for reusing its figures.

Table

Segment tables are reproduced only where the publisher's terms allow it, for example an explicit free-use-with-credit licence.

Quote

Published factual figures reported in our own wording and presentation, each attributed and linked, where the publisher's terms do not specifically restrict citing the figures. We never copy a publisher's charts, tables or prose, and reporting a figure is not a claim that the publisher has granted a licence.

Link only

The report is named and linked, but none of its figures are shown, where the publisher's terms require permission to reproduce content.

Why sources disagree

Definitions. Unique or total opens, campaigns or automated emails, with or without Apple's automatic opens.

Who is sending. Each platform reports on its own customers: online stores, newsletters, small businesses or enterprises.

Median or average. A median resists a few extreme senders; an average does not.

Data windows. A 2021 figure and a 2025 figure describe different inboxes.

Selection. Platforms choose which accounts to include, such as active senders only or lists above a minimum size.

Keeping pages current

Every source is re-opened each quarter to confirm the link still works and to look for a new edition.
A new edition adds new figures next to the old ones. We do not overwrite history.
If a source goes offline, its figures stay on the page with a note and the date we last saw it.
A benchmark page needs at least two current graded sources. If it drops below that, we withdraw it until it has two again.

Limitations

The figures are reported by the platforms themselves about their own customers. We do not measure these metrics, and we cannot check a publisher's raw data. Where a publisher does not state its sample, statistic or data window, we say so next to the figure.

Corrections

Found an error, a newer edition or a source we should add? Tell us. We check every report and note corrections on the page.