Is per-send or per-subscriber email pricing cheaper?

It depends on your send intensity: monthly sends divided by subscriber count. Below about 1, meaning you do not email your whole list every month, per-send pricing is cheaper and the gap widens as the list grows. Above about 1, per-subscriber pricing can be cheaper.

Why does my email bill go up when I have not sent more email?

Because your tool meters subscribers rather than sends, so the bill tracks list growth. Crossing a subscriber tier raises the price whether or not you send anything that month.

Does transactional email count toward a send allowance?

On day3, yes: password resets, receipts and magic links draw on the same monthly allowance as campaigns, which is usually cheaper than paying a second vendor. Add your transactional volume to your monthly sends before choosing a tier.

What happens if I go over my monthly email limit?

On day3 sending pauses at the cap with no overage charge. Not every tool works that way, so it is worth checking: an automatic overage on a per-send plan can turn one mistargeted campaign into a large invoice.

Do unused emails roll over to next month?

On day3, no, and on most tools, no. Allowances reset each billing period. If you send rarely but heavily, size the plan to the month you actually send rather than to your monthly average.

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PricingAugust 12, 20267 min read

Per-subscriber vs per-send email pricing, worked out

Almost every email tool meters one of two things: how many people are on your list, or how many emails you send them. Which is cheaper is not a matter of opinion, and you can work it out with one division.

The short version

Divide your monthly sends by your subscriber count. Call it send intensity.
Below roughly 1, meaning you do not email everyone every month, per-send pricing is cheaper and the gap grows as your list does.
Above roughly 1, meaning a weekly or daily letter, per-subscriber pricing can be cheaper. Small list, high frequency is the case where it wins.
The two curves diverge over time for most software teams, because lists compound and release cadence does not.
Per-subscriber pricing has a hidden cost: it makes an accurate list expensive, so it quietly encourages you to keep a worse one.

The one number that decides it

Take the number of emails you send in a typical month and divide it by the number of people on your list. If you have 20,000 subscribers and send two campaigns to all of them, that is 40,000 sends over 20,000 subscribers, an intensity of 2. If you have 20,000 subscribers and send one campaign every other month, it is 10,000 over 20,000, an intensity of 0.5.

Low intensity favours a per-send meter, because you are paying for the small number rather than the large one. High intensity favours a per-subscriber meter, because the subscriber count is fixed no matter how often you hit send. Everything else in this comparison is detail.

The same list, four sending cadences
Subscribers	Cadence	Sends / month	Intensity	Better meter
20,000	Every other month	10,000	0.5	Per send
20,000	Monthly	20,000	1.0	Roughly level
20,000	Weekly	80,000	4.0	Per subscriber
2,000	Daily	60,000	30.0	Per subscriber, clearly

Why software teams usually land below 1

A list compounds. Every launch, every mention, every month of organic signups adds people, and nothing removes them except unsubscribes and bounces. It is a stock that only grows.

Sending does not work like that. For a product team, sending is gated by having something worth announcing, which is gated by engineering time. You do not ship twice as often because your list doubled. So the numerator stays roughly flat while the denominator climbs, and intensity falls month after month.

That is the structural reason per-subscriber pricing feels increasingly unfair to a growing software company and feels fine to a daily newsletter. The newsletter's intensity is pinned high by its format. The software company's drifts downward by default.

The quiet cost of a per-contact meter

There is a second effect that does not show up in a spreadsheet. When contacts cost money, every decision about your list becomes partly a billing decision.

Do we put trial signups on the list, or only paying customers?
Should we delete the contacts who have not opened anything in a year?
Do we keep the churned accounts, in case they come back?
Can we afford to keep the people who unsubscribed, as a record that they did?

Every one of those has a correct answer from your business's point of view and a different answer from your invoice's. Pruning a list to reduce a bill is a strange thing to be doing, and keeping no record of who opted out is actively risky: if you cannot see that someone unsubscribed in 2024, nothing stops a fresh import mailing them in 2026.

When subscribers are free, all four questions collapse into one answer: keep the accurate list. That is worth something, even though it does not appear on either side of the price comparison.

What to check beyond the meter

Price per email is the headline, but three mechanics change the real cost more than the rate does.

Overage behaviour. Does exceeding your allowance charge you automatically, throttle you, or stop sending? An automatic overage on a per-send plan can turn a mistake into an invoice, which is why a hard cap is worth having.
Rollover. Most allowances reset monthly and do not carry forward, so an occasional sender should size the plan to the month they actually send rather than to their annual average.
Whether transactional counts. If your app sends password resets and receipts, running them through the same allowance is usually cheaper than a second vendor, but only if the allowance is sized for both. Add them to the numerator before you pick a tier.

How day3 prices it

day3 meters sends only. Subscribers are unlimited on every paid plan, transactional email through the API draws on the same monthly allowance as campaigns, and there is no overage: sending pauses at the cap rather than billing past it. Plans run from $1/mo for 1,000 emails up to $220/mo for 1,000,000, and you can move between them as your sending changes.

Which means the honest summary of who should pick it: if your intensity is comfortably below 1 and your list is growing, this model is built for you. If you send a daily letter to a few thousand people, it is not, and a per-subscriber tool will serve you better.

Questions

Is per-send or per-subscriber email pricing cheaper?: It depends on your send intensity: monthly sends divided by subscriber count. Below about 1, meaning you do not email your whole list every month, per-send pricing is cheaper and the gap widens as the list grows. Above about 1, per-subscriber pricing can be cheaper.
Why does my email bill go up when I have not sent more email?: Because your tool meters subscribers rather than sends, so the bill tracks list growth. Crossing a subscriber tier raises the price whether or not you send anything that month.
Does transactional email count toward a send allowance?: On day3, yes: password resets, receipts and magic links draw on the same monthly allowance as campaigns, which is usually cheaper than paying a second vendor. Add your transactional volume to your monthly sends before choosing a tier.
What happens if I go over my monthly email limit?: On day3 sending pauses at the cap with no overage charge. Not every tool works that way, so it is worth checking: an automatic overage on a per-send plan can turn one mistargeted campaign into a large invoice.
Do unused emails roll over to next month?: On day3, no, and on most tools, no. Allowances reset each billing period. If you send rarely but heavily, size the plan to the month you actually send rather than to your monthly average.