SMS vs Email Sends, Klaviyo

SMS vs Email Sends for the selected period. Grouped bars comparing SMS send volume against email send volume per period. The channel-mix view: SMS is lower volume but higher cost and higher per-message conversion. How to read it, why it matters, and how to act on it.

Metrics type: Supporting Metrics • Category: Email Marketing

Your two messaging channels side by side. Email is high-volume and near-free; SMS is low-volume, paid, and converts harder per send. This card shows the balance you are striking.

At a glance

A grouped-bar comparison of SMS send volume against email send volume per period bucket, so you can see the channel mix at a glance. The two channels behave very differently: email is high-volume and effectively free per send, while SMS is low-volume, consent-gated, billed per message, and typically converts much harder per send. This card exists to make the trade-off visible, because the right channel mix is not “send everything on both” but “use email for reach and SMS for high-intent moments where its higher per-message return justifies the cost”. Reading the two bars together stops you from over-investing in expensive SMS volume that is not converting, or from leaning so hard on email that you under-use the higher-value channel. It is a planning view, not an alert view: use it to decide where the next message should go.

What it counts	Email send volume and SMS send volume per period bucket, plotted as grouped bars for direct comparison.
API endpoint + statistics field	POST /api/campaign-values-reports and POST /api/flow-values-reports, returning the recipients statistic per channel, split into email and SMS series.
Email vs SMS aggregation	Both channels, shown side by side rather than blended. Each bar is a separate channel total for the bucket.
MPP impact	None. Apple Mail Privacy Protection affects email opens only, not send counts, so neither bar is distorted by MPP.
Chart type	Grouped bar.
Time window	30D vsP
Alert trigger	A pronounced shift in the channel mix against the recent baseline, for example a surge in SMS volume, which on a paid channel warrants a spend and return check.
Roles	owner, marketing

Calculation

Calculated automatically from your Klaviyo data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.

Worked example

An illustrative gifts brand that uses email broadly and SMS selectively for time-sensitive offers. Reading the dashboard on 14 Apr 26 for the trailing 30 days (14 Mar 26 to 12 Apr 26), the grouped bars by week look like this (illustrative figures):

Week	Email sends	SMS sends	SMS share of sends
14-20 Mar 26	96,000	6,000	5.9%
21-27 Mar 26	98,000	6,200	5.9%
28 Mar-3 Apr 26	99,000	12,400	11.1%
4-12 Apr 26	101,000	12,800	11.3%

Email volume is ~16x SMS volume across the window
SMS share doubled from ~6% to ~11% in weeks 3 to 4 (a flash-sale push)
Email per send is near-free; SMS per send carries a real carrier cost

Five observations:

1. Email dwarfs SMS on raw volume, and that is normal. Email runs roughly sixteen times the SMS volume here. The point of the card is not to close that gap but to show the balance, because the channels play different roles.
2. The SMS bar grew in weeks 3 and 4 for a flash sale. SMS share doubled from about 6% to 11%. This is the deliberate use of a paid, high-intent channel for a time-sensitive moment, exactly where SMS earns its cost.
3. Cost asymmetry is the whole reason to compare. Adding email volume is nearly free; adding SMS volume is real spend. So a rising SMS bar is a spending decision, and this card is where you notice it before the bill does.
4. Lower SMS volume can still out-earn its share. Because SMS revenue per recipient typically runs well above email, the small SMS bar can contribute a disproportionate slice of revenue. Read this alongside Revenue per Send to see value, not just volume.
5. Use the mix to plan, not to equalise. The aim is not to make the bars match. It is to send email for broad reach and reserve SMS for moments where its higher per-message conversion justifies the cost. If the SMS bar grows without conversion keeping up, pull it back.

Sibling cards merchants should reference together

SMS vs Email Sends is the channel-mix planning view. Pair it with these:

Card	Why pair it with SMS vs Email Sends
Total Sends	The all-up email volume behind one of the bars. Use it to drill into the email side of the mix.
SMS Sends	The SMS bar in detail, including its role as your SMS spend line.
SMS Overview	The cockpit view of the SMS side, so a growing SMS bar can be judged on its returns.
Email Attributed Revenue	The email payoff. Pair send volume with revenue to weigh email reach against SMS value.
Revenue per Send	The value-per-message read. This is what tells you the cheaper channel is not always the better one.

Reconciling against Klaviyo

Where to look in Klaviyo:

• Klaviyo → Analytics → Performance, then compare the email and SMS channel views over the same period.
• Klaviyo → Campaigns, filtered by channel, to see email and SMS recipient counts side by side.
• Klaviyo → Flows, filtered by channel, for triggered email and SMS volume.

Why our number may legitimately differ:

Reason	Direction of divergence
Channel scoping. Klaviyo’s default dashboards often show one channel at a time, so a single-channel view will only match one of our two bars.	Matches one bar, not both.
Time zone. Vortex IQ buckets by UTC day; Klaviyo uses your account time zone. Messages near midnight can fall into a different period.	Either direction, usually marginal.
Campaign plus flow scope. Each bar blends campaigns and flows. A campaign-only Klaviyo view will read lower on the corresponding bar.	Ours reads higher than a campaign-only view.
Carrier filtering (SMS only). Some SMS messages are filtered at the carrier and may be counted differently between a live view and our snapshot.	SMS bar can read marginally low.
Page caps. Values reporting pages at 50 records per pull, so very high volumes can see slight aggregation truncation on either series.	Either bar can read marginally low for heavy senders.

Known limitations / merchant FAQs

Why is my SMS bar so much smaller than my email bar? Because the channels are built differently. Email reach can be large and is nearly free per send, while SMS reach is gated by explicit consent and billed per message. A small SMS bar next to a large email bar is the normal, healthy shape; the SMS bar earns its keep on value per send, not volume.

Should I try to grow the SMS bar to match email? No. The goal is the right mix, not equal bars. SMS is best reserved for high-intent, time-sensitive moments where its higher per-message conversion justifies the cost. Growing SMS volume indiscriminately just grows the bill.

Why compare sends rather than revenue? Because this card is the volume and effort view. Sends show where you are spending attention and, on SMS, money. Pair it with revenue cards to see whether the volume in each bar is paying off; the comparison only makes sense with both.

Does each bar include flows or only campaigns? Both. Each channel bar blends campaign and flow sends for a complete volume picture. A campaign-only Klaviyo view will read lower on whichever bar you compare against.

My SMS bar jumped, should I worry? Check the return. A deliberate SMS push for a sale is fine if conversion and revenue per send hold up. An unplanned jump, or a jump where conversion fell, is worth investigating because every extra SMS is real spend.

Does Apple Mail Privacy Protection skew this comparison? No. MPP affects email opens only, not send counts. Both bars here are send volumes, so neither is distorted by MPP.

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Tracked live in Vortex IQ Nerve Centre

SMS vs Email Sends is one of hundreds of KPI pulses Vortex IQ tracks across Klaviyo and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English.

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