What RPM is and why it exists
RPM (revenue per mille — revenue per thousand) is a normalised form of the RPV (revenue per visitor)
metric. The formula:
RPM = (Revenue / Number of visitors) × 1,000
If a store took $1,500,000 in a month from 500,000 unique visitors:
RPV = 1,500,000 / 500,000 = $3 per visitor
RPM = 3 × 1,000 = $3,000 per 1,000 visitors
RPM is particularly convenient when comparing channels or segments with substantially different
traffic — “per thousand” as a unit makes the numbers legible instead of leaving them as small
fractions.
RPM as a function of conversion and order value
RPM decomposes into its components:
RPM = CR × AOV × 1,000
At CR = 2% and AOV = $150:
RPM = 0.02 × 150 × 1,000 = $3,000
Which means any improvement in CR or AOV lifts RPM directly. A rise in CR from 2% to 2.2% (+10%)
produces an RPM of $3,300 — the same 10% gain. Personalization that affects both components at once
produces a multiplicative effect.
Comparing channels with RPM
| Channel | Visitors | Revenue | RPM |
|---|---|---|---|
| SEO | 600,000 | $1,800,000 | $3,000 |
| Email campaign | 80,000 | $480,000 | $6,000 |
| Paid search | 150,000 | $750,000 | $5,000 |
| Direct | 200,000 | $800,000 | $4,000 |
Email shows the highest RPM — the audience is warm and already familiar with the store. SEO, despite
its enormous volume, has the lowest RPM: it carries a lot of informational traffic with no intent to
buy.
Tip: when planning budget, read RPM alongside the cost of the channel (CPC, CPM for paid
traffic). A channel with a high RPM but expensive acquisition can deliver a lower ROI than SEO with
a low RPM and near-zero variable cost.
RPM by category and segment
RPM is useful not only for channels but for analysing the earning power of individual sections of
the site:
- An electronics category with low conversion can still show a high RPM, thanks to a large AOV
- An accessories category with high conversion but a low AOV can end up at a comparable RPM
Analysing RPM by category helps prioritise personalization work: is it worth investing effort in a
section whose RPM was low to begin with?
The limits of RPM
RPM ignores margin. A category with an RPM of $5,000 at a 15% margin is worth less than a category
with an RPM of $3,500 at a 40% margin. For strategic decisions, pair RPM with gross margin, or use
RPM × gross margin as the working metric.