If you send a lot of SMS, the cheaper-per-segment tier always looks better on a spreadsheet. The question nobody answers cleanly is: at what volume does moving down a tier actually put money back in your account — and at what point does the difference between $0.0125 and $0.0028 stop being a rounding error and start being a real line item?
Full disclosure: I work for ReadySMS, so I'm using our published numbers throughout. The nice thing is they're public and itemized, so you can check every figure against our pricing page instead of taking my word for it.
This post walks the exact crossover math. By the end you'll know what monthly send volume justifies pushing into Growth, and where the Enterprise conversation ($0.0028 floor at 500K+ segments/month) is worth having with us versus where it saves you basically nothing.
The numbers we're working with
Two components make up every send: the per-segment platform rate, which drops by tier, and a flat $0.0045 carrier pass-through that's the same at every tier and billed separately (not marked up). If you want the full story on why that line item exists and why most providers hide it inside their "per-message" price, I wrote about that in the $0.0045 line item decoded.
| Tier | Volume / month | Platform / segment | + Carrier | All-in / segment |
|---|---|---|---|---|
| Starter | 0–50,000 | $0.0155 | $0.0045 | $0.0200 |
| Growth | 50,000–500,000 | $0.0125 | $0.0045 | $0.0170 |
| Enterprise | 500,000+ | as low as $0.0028 | $0.0045 | $0.0073 |
The carrier fee never moves, so all your savings live in that platform column. That matters more than it looks: at Enterprise the platform rate drops well below the carrier fee itself, meaning further platform discounts have a shrinking effect on your all-in cost. We'll come back to that.
How tiers actually apply
These are volume tiers, not commitments you pre-pay for. Your effective rate follows your monthly send volume. So the real question isn't "should I sign up for Growth" — it's "is my send volume high enough that the lower rate is already mine, and how much is the next tier down worth?"
To keep the comparisons honest, I'm going to compare each tier's all-in rate against the tier above it and show the per-segment delta, then multiply by volume.
Crossover one: Starter to Growth (the 50K line)
This is the most common breakpoint for growing senders. Starter is $0.0200 all-in; Growth is $0.0170. The delta is $0.0030 per segment.
At the Growth entry point of 50,000 segments/month:
- 50,000 × $0.0030 = $150.00/month saved versus paying Starter rates on that volume.
That's not theoretical — it's the same mechanism my colleague worked through in the tier breakpoint post: moving base sends across a tier line adds the delta straight to an agency's monthly margin. Same mechanism, scaled.
A worked send example, because per-segment numbers feel abstract until you attach a campaign to them. Say you send a 175-character promo with one emoji. The emoji forces unicode encoding, which drops the limit to 67 characters per multipart segment — so 175 characters is 3 segments, not 1.
- 90,000 contacts × 3 segments = 270,000 segments
- At Growth: 270,000 × $0.0170 = $4,590
- At Starter rates on the same volume: 270,000 × $0.0200 = $5,400
- Difference: $810 on a single blast.
(If you'd written that same message in plain GSM-7 with no emoji, 175 characters is 2 segments of 153, and the whole thing costs you a third less. Worth remembering before you reach for the emoji.)
Crossover two: Growth to Enterprise (the 500K line)
Here's where the math gets dramatic. Growth is $0.0170 all-in; Enterprise at its floor is $0.0073. The delta is $0.0097 per segment — a far bigger per-segment gap than the Starter-to-Growth jump.
At the Enterprise entry point of 500,000 segments/month:
- 500,000 × $0.0097 = $4,850/month saved versus Growth rates.
Notice the proportion, too. Going from Starter to Growth cut your all-in rate by about 15%. Going from Growth to Enterprise cuts the platform rate from $0.0125 to $0.0028, and your all-in cost drops from $0.0170 to $0.0073 — but the fixed carrier fee now dominates: at $0.0073 all-in, most of what's left is carrier fee you can't compress.
The practical read: every tier down is worth chasing, but the carrier pass-through sets a hard floor on how cheap SMS can ever get. Nobody — us, a wholesale CPaaS provider, anyone routing on registered 10DLC — gets under that carrier fee. If a vendor quotes you an all-in number below the carrier pass-through, they're either eating margin temporarily or they're not telling you the whole bill.
The breakeven nobody asks about: is it worth restructuring to hit a tier?
Sometimes a sender is sitting just under a threshold — say 480,000 segments/month, just shy of Enterprise's 500,000. The temptation is to manufacture volume to cross the line. You'd be paying for 20,000 segments you didn't need to capture a $0.0097 discount. That's about $146 of new spend (20,000 × $0.0073) to save roughly $4,656 (480,000 × $0.0097) — which does net positive, but only because you genuinely send near the line.
The honest version: tier optimization is a measurement exercise, not a growth hack. Count your real segment volume — segments, not messages, and remember unicode and multipart inflate it — then check which side of a threshold you're on. Our cost calculator does this if you'd rather not build the spreadsheet.
A quick reference: monthly savings by tier crossing
Savings shown are the per-segment delta times the volume at the tier's entry point. Real savings scale linearly with whatever you actually send above that.
- Starter → Growth ($0.0030 delta), at 50,000/mo: ~$150/month
- Growth → Enterprise ($0.0097 delta), at 500,000/mo: ~$4,850/month
The pattern: the deltas grow, but so does the volume required to earn them. Below roughly 50K/month, tier optimization is worth little and your energy is better spent on message efficiency — shorter copy, dropping unnecessary emoji, killing dead contacts. Approaching 500K, the dollars are very real and worth planning around.
Where the bigger money usually hides
Before you spend a week negotiating an Enterprise rate, do the boring math on segment count. A high-volume sender who trims an average message from 3 segments to 2 cuts a third off the entire bill — at every tier, instantly, with no negotiation. That's a bigger lever than a tier jump for most senders.
Two cost leaks worth auditing first:
- Unicode creep. One stray emoji or a smart-quote pasted from a doc forces 70-char segments. On a million-segment month, that's the difference between a $7,300 bill and a $10,000+ one. More on this in reducing SMS costs.
- Sending to dead numbers and litigators. You pay per segment regardless of whether it lands. Running a DNC and litigator scrub at $0.005/contact removes numbers you shouldn't be paying to message anyway — and removes TCPA exposure that dwarfs any tier discount.
The practical takeaway
Tier savings are real and they compound, but they follow a clear shape: modest under 50K/month (~$150/month at the Growth line), and worth a direct conversation at 500K+ where Enterprise opens the $0.0028 floor (~$4,850/month and up). The carrier pass-through is the floor under all of it — no tier escapes it, and any quote that pretends to should make you suspicious.
If you're north of 50K segments a month, the fastest honest answer is to run your real volume through the calculator, then check your average segment count per message. If you're approaching 500K and want the Enterprise rate quoted against your actual traffic, that's a conversation we're happy to have — but only after you've squeezed the segment math, because that's usually where the larger number was hiding the whole time.