Merchants keep asking for a magic number of emails per week, but the measured data settles a narrower question: what a send is worth, what happens above 5,000 messages a day, and why the answer is about deliverability rules and return math rather than a calendar.
Most advice on email frequency answers a question nobody measured: how many sends per week keeps subscribers happy. The data that actually exists answers a different and more useful question, which is what kind of send earns money and what a mail provider requires once volume crosses a line. Neither of those is a weekly count, so a merchant who came here looking for “send three times a week” will not find that number, because it is not in any measured source. What is in the sources is a return figure, an automation gap, and a hard rule change tied to daily volume, and all three matter more than a calendar.
Email marketing generates between $36 and $40 for every dollar spent, according to multiple industry sources cited in the Omnisend report. Omnisend’s own US merchants do better than that average, seeing $76 back for every dollar spent, about double the broader figure. Neither number says whether that return came from four sends a month or forty. A high return per dollar spent is consistent with a lot of different sending patterns, so treating it as permission to send more, or as proof that less is better, both go beyond what the number supports.
The clearest frequency-adjacent signal in the data is not about how often to send but about what triggers a send. Automated emails reached a 38% open rate and generated $2.87 per email, compared to $0.18 for the same measure without automation. That gap, roughly sixteen times the revenue per email, is far larger than any plausible effect of adding or removing one weekly newsletter. Automated SMS shows the same shape: $0.74 per send compared to $0.15. Put together, the sending pattern that the data actually rewards is one built on triggers, behavior, dates, cart activity, rather than one built on a fixed number of sends per week.
| Signal | Measured value | Source |
|---|---|---|
| Industry return per dollar spent | $36 to $40 | Omnisend report |
| Omnisend US merchant return per dollar spent | $76 | Omnisend report |
| Automated email open rate | 38% | Omnisend report |
| Automated email revenue per send | $2.87 vs $0.18 | Omnisend report |
| Automated SMS revenue per send | $0.74 vs $0.15 | Omnisend report |
| Birthday email average order value | $744.37 | Omnisend report |
| BFCM email-driven revenue | part of $112.6 billion | Omnisend report |
The one place frequency shows up as a hard number is on the delivery side, not the engagement side. Google’s sender guidelines state that starting February 1, 2024, all email senders to Gmail accounts must meet a baseline set of requirements. A separate and stricter set of requirements applies to senders who send 5,000 or more messages a day, effective the same date. Senders who were already sending more than 5,000 emails a day before that date are told to keep following the guidelines going forward, so the rule did not grandfather high-volume senders out of it. This means a store growing its list and its send volume will, at some point, cross a threshold where the rules for its program change, independent of whatever cadence its marketing team picked.
Google’s documentation also gives a specific operational instruction tied to a specific error. If a sender gets error 4.7.28, the guidance is to stop sending for at least 10 minutes, and after that 10 minute window, to send emails from a single connection. That is a rate-limiting response to a signal from Google’s system, not a general cap on how many campaigns a week a store can run.
None of the measured sources here state an ideal number of campaigns per week, so any such number offered elsewhere is not coming from this data. What the data supports is building a program around automation first, since automated email and automated SMS both show large revenue and open rate advantages over their non-automated counterparts, and around date-triggered sends like birthday messages, which produced an average order value more than 4 times the overall average. It also means checking send volume against Google’s February 1, 2024 requirements, especially the added requirements that apply once daily volume reaches 5,000 messages, before scaling any calendar-based sending up.
The numbers in this report were read from Google’s published sender guidelines as loaded on September 5, 2026, and from Omnisend’s email marketing statistics report as loaded on September 8, 2026. A merchant deciding on frequency should treat the automation gap as the priority to fix before touching the count of scheduled campaigns, and should check current daily send volume against the 5,000-message threshold before assuming existing sending practices still comply.
The facts here do not contain a weekly number, and no measured source in this set states one, so any specific weekly count is invented rather than supported. What is measured is that automated, triggered emails outperform the alternative by a wide margin, reaching a 38% open rate and $2.87 per email against $0.18. That points toward building sends around triggers such as behavior and dates rather than picking a fixed weekly cadence and holding to it regardless of what a subscriber does.
Volume changes what Google requires of a sender rather than punishing volume on its own. Google's guidelines set requirements for all senders to Gmail starting February 1, 2024, and a separate, stricter set of requirements for anyone sending 5,000 or more messages a day starting the same date. Senders who were already over 5,000 emails a day before February 1, 2024 are told to keep following the same guidelines going forward. So the frequency question at scale is really a compliance question, not a subscriber-fatigue question.
Google's documentation gives one concrete instruction tied to a specific error, error 4.7.28: stop sending for at least 10 minutes. After that 10 minute pause, Google's guidance says to send emails from a single connection. That is a rate-limiting instruction, not a frequency cap on daily sends, and it only shows up when a sender hits that particular error.
The Omnisend data says yes on a per-order basis: birthday messages produced an average order value more than 4 times higher than average, at $744.37. That is a single-send, date-triggered email, not a recurring weekly one, which supports the idea that some of the highest-value sends are rare and personal rather than frequent and broad.
The measured data has SMS working alongside email rather than instead of it. Automated SMS generated $0.74 per send compared to $0.15 for the counterpart figure in the same report, a similar pattern to the automated email lift over non-automated email. Neither number says how many sends per week is right for either channel, so this argues for automation as the lever, not a channel swap.