Here's a conversation I've had with a dozen GHL agency owners: "We buy SMS at two cents, rebill our clients at three, and pocket a penny per message." Clean spread. Except it's usually wrong, and the reason it's wrong is a line item most people mentally round away — the carrier pass-through.
Full disclosure: I work for Ready, an SMS platform built for GHL agencies and anyone else sending text at scale. I'm writing this because the pass-through is the single most common thing agencies forget when they build their rebill sheet, and the mistake is invisible until you reconcile a heavy send month and your margin is half what the spreadsheet promised.
The number you're not counting
On Ready, an outbound segment on the Standard tier costs $0.02. But that's not your all-in cost. There's a separate, itemized $0.0045 per segment carrier pass-through — the fee the carriers charge to move the message, billed transparently and not marked up.
So your true landed cost per segment on Standard is:
$0.02 + $0.0045 = $0.0245
We keep it as its own line on purpose — you should always be able to see exactly what's platform and what's carrier (here's why that transparency matters). But the side effect is that agencies read the $0.02 headline number, build their rebill on it, and quietly leave the $0.0045 out of the cost side.
What that does to your "penny of margin"
You rebill at $0.03. You think your cost is $0.02. So you think margin is $0.01/segment — a 50% markup, feels great.
Reality:
| Per segment | |
|---|---|
| Client pays (your rebill) | $0.03000 |
| Ready base rate (Standard) | $0.02000 |
| Carrier pass-through | $0.00450 |
| Your true cost | $0.02450 |
| Actual margin | $0.00550 |
You didn't keep a penny. You kept $0.0055 — 45% less than you budgeted. Your effective markup isn't 50%, it's about 22%.
Now scale it. Say a client sends 40,000 segments in a month:
- What you thought: 40,000 × $0.01 = $400 margin
- What you actually made: 40,000 × $0.0055 = $220 margin
That $180 gap is per client, per month, and it's silent. Nobody complains. The client pays their $1,200. Your books just quietly show less profit than the model said, and if you don't reconcile carefully you'll blame it on "fees" without ever finding the leak.
Why it hides so well
Three reasons this slips past sharp operators:
- The headline rate is the sticky number. You quote yourself "two cents" once and it lodges in your head as cost. The pass-through is a rounding error per message, so your brain files it under noise.
- It's fractions of a cent. $0.0045 doesn't feel like it matters until you multiply by 40,000 or 400,000.
- Resellers that bundle it hide it worse. Plenty of providers fold the carrier fee into a single rounded "per-message" price so you never see it as a line. That feels simpler, but it means you can't separate platform cost from carrier cost when you build your own markup — more on that here. Ready splitting it out is the thing that lets you price correctly; you just have to actually add both lines.
The corrected markup table
Build your rebill off the all-in cost, not the base rate. Here's the honest math at a few common rebill prices on the Standard tier ($0.0245 true cost):
| Your rebill | True cost | Margin/seg | Real markup | Margin on 40K sends |
|---|---|---|---|---|
| $0.025 | $0.0245 | $0.0005 | ~2% | $20 |
| $0.030 | $0.0245 | $0.0055 | ~22% | $220 |
| $0.035 | $0.0245 | $0.0105 | ~43% | $420 |
| $0.040 | $0.0245 | $0.0155 | ~63% | $620 |
| $0.045 | $0.0245 | $0.0205 | ~84% | $820 |
Two things jump out. First, rebilling at $0.025 — which some agencies do thinking they're marking up 25% — actually nets almost nothing once the pass-through is counted. Second, if you want a genuine 50% markup, your rebill needs to be around $0.037, not $0.03.
For where the ceiling is before clients start auditing that line item, we worked through the markup ceiling separately.
What happens past 50,000 segments
Your cost side isn't fixed. Once an account passes 50,000 segments in a calendar month, the base rate drops automatically from $0.02 to $0.016 — Growth tier. Nobody picks it; it just applies. All-in that's:
$0.016 + $0.0045 = $0.0205 per segment
If your rebill stays at $0.03, your margin on the segments above 50K jumps:
- Below 50K: $0.03 − $0.0245 = $0.0055/seg
- Above 50K: $0.03 − $0.0205 = $0.0095/seg
Your blended margin improves, but note the pass-through doesn't drop — the $0.0045 is a carrier cost, not a platform one, so it rides along at every tier. When you model your blended rate across the breakpoint, keep the pass-through constant. The blended-rate math across that 50K line is worth reading in full, and if you're deciding whether the tier jump is worth chasing, there's a piece on exactly that.
Multi-segment and emoji: the multiplier you also forget
The pass-through and the base rate are both per segment, not per message. That matters because "one text" is often more than one segment.
- Plain GSM-7 text: 160 characters per segment; longer messages split into 153-char parts.
- Add a single emoji or unicode character and the whole message drops to 70 chars per segment (67 for multipart).
Worked example. A client sends a 175-character promo with one emoji. That's unicode, so 70 chars per segment — 175 characters lands as 3 segments. Blast it to 5,000 contacts:
- Segments billed: 5,000 × 3 = 15,000
- Your cost (Standard): 15,000 × $0.0245 = $367.50
- Rebill at $0.03: 15,000 × $0.03 = $450
- Your margin: $82.50
If you'd priced that blast as "5,000 messages at a penny each = $50 margin," you'd be off in both directions — more revenue, but also more cost — and your per-segment margin is still the $0.0055 truth, just multiplied by three. The takeaway: quote clients in segments, model your cost in segments, and remember the pass-through applies to every one of them.
How to fix your sheet in ten minutes
- Replace $0.02 with $0.0245 everywhere "cost" appears in your model. Or list the pass-through as its own row so it's never absorbed.
- Reprice rebill off the all-in number. Want 50% real margin? Rebill at ~$0.037, not $0.03.
- Quote clients per segment, not per message, and warn them emojis and long copy multiply the count. This also protects you from an angry "why was my bill 3x?" email after a unicode-heavy campaign.
- Keep the carrier line visible to your client if you rebill transparently. It's the same posture Ready takes with you, and it heads off audits — the client sees platform cost and carrier cost separately and stops assuming your whole markup is padding.
- Model the 50K breakpoint if any account is close. The base rate drops; the pass-through doesn't.
The practical takeaway
The $0.0045 carrier pass-through isn't a gotcha — it's an honest, un-marked-up line item that we deliberately keep visible so you can price correctly. The failure mode is purely a mental one: reading the base rate as the full cost. Do that at scale and you'll spend a quarter wondering where your margin went.
Rebuild your rebill sheet on the all-in $0.0245, requote where you're thin, and your penny-of-margin story becomes true again — just at a slightly higher rebill number than you started with.
If you want to sanity-check your own numbers against current pricing, the tiers and the itemized pass-through are all laid out on the Ready product page, and you can start with 2,500 free credits to run a real blast and reconcile the actual line items before you touch a client bill.