Your annual appeal letter costs money before a single dollar comes back. Printing, folding, the reply envelope, the postage, the list rental if you're prospecting. By the time it hits a mailbox, you've spent somewhere between $0.45 and $0.75 per piece to ask. That's the part development directors have internalized so deeply they stop questioning it — direct mail is expensive to send, so the whole model is built around a response rate low enough that most pieces are a loss and a small fraction of large gifts carries the appeal.
Full disclosure: I work for ReadySMS, so I have a horse in this race. But the point of this post isn't "text everyone instead of mailing them." It's to put three channels on the same spreadsheet — direct mail, email, SMS — using the metric that actually matters to a board: cost per dollar raised. Because the answer is more nuanced than any channel evangelist will tell you, and knowing exactly where SMS wins and loses is worth more than a blanket recommendation.
The metric that matters: cost per dollar raised
Response rate is a vanity number if you don't attach cost to it. A channel with a 0.5% response rate can beat a channel with a 4% response rate if it's cheap enough per contact and the average gift holds up. So the model has three inputs per channel:
- Cost per contact — what it costs to put the ask in front of one person.
- Response rate — the share who give.
- Average gift — what a responder gives.
Multiply response rate by average gift and you get revenue per contact. Divide cost per contact by revenue per contact and you get cost to raise $1. That last number is the one to compare.
I'll use round industry approximations for response rates — treat them as directional, not gospel, because your file behaves differently than the sector average. Every nonprofit's numbers are its own.
Setting up the model: a mid-size annual appeal
Say you're a development director at an organization with a house file of 20,000 reachable donors and lapsed donors. You're running your fall annual appeal. Here's a defensible set of assumptions for each channel.
Direct mail:
- Cost per piece (print + fold + reply envelope + first-class-ish postage, prospecting excluded): ~$0.55
- Response rate on a warm house file: ~4% (mail still pulls the highest response of the three, especially with older donors)
- Average gift: ~$85 (mail donors skew older and give larger checks)
Email:
- Cost per email: effectively ~$0.001 on any reasonable ESP plan, call it a rounding error
- Response rate: ~0.2% (email appeal conversion is low; most nonprofit email fundraising leans on volume)
- Average gift: ~$55
SMS:
- Cost per segment on ReadySMS Standard: $0.02 + $0.0045 carrier = $0.0245. A well-written appeal with a link runs 2 segments, so ~$0.049 per contact.
- Response rate on an opted-in list: ~1–2% (opted-in SMS donor lists convert far above email; I'll use 1.5%)
- Average gift: ~$45 (mobile giving skews toward smaller, impulse-friendly amounts)
The side-by-side table
Here's the full model on our 20,000-contact file. SMS numbers use two segments per message at ReadySMS Standard pricing.
| Direct Mail | SMS | ||
|---|---|---|---|
| Cost per contact | $0.55 | ~$0.001 | $0.049 |
| Response rate | 4% | 0.2% | 1.5% |
| Average gift | $85 | $55 | $45 |
| Revenue per contact | $3.40 | $0.11 | $0.675 |
| Cost to raise $1 | $0.162 | $0.009 | $0.073 |
| Cost to reach 20,000 | $11,000 | $20 | $980 |
| Responders | 800 | 40 | 300 |
| Total raised | $68,000 | $2,200 | $13,500 |
| Net raised | $57,000 | $2,180 | $12,520 |
Read the "cost to raise $1" row first. Email is the cheapest per dollar — it costs less than a penny to raise a dollar — but it raises almost nothing in absolute terms because the response rate is so low. Direct mail costs the most per dollar (16 cents) but raises the most gross revenue because average gift and response rate are both high. SMS sits in between: 7.3 cents to raise a dollar, and it pulls real money — $13,500 net — off a file where email pulled $2,180.
What the table is actually telling you
None of these channels "wins." They do different jobs.
Direct mail wins on gross dollars and large gifts. If a channel has to carry your appeal, it's still mail — the older, higher-capacity segment of your file gives through the mailbox, and $85 average gifts don't happen over text. Don't kill your mail program because a spreadsheet says SMS is more efficient per dollar. Efficiency isn't the goal; net revenue is, and mail still produces the most of it here.
Email wins on marginal cost. At effectively free, there's no reason not to send it. The problem is that "free to send" makes people over-send, and inbox fatigue kills the response rate over time. Email's job is reach and reinforcement, not conversion.
SMS wins on cost-efficiency per dollar among the paid channels, and on speed. It raised nearly $12,500 net at a fraction of mail's spend. And it does something mail can't: it converts inside a window. A "we're $4,000 short with 6 hours left" text on year-end raises money mail could never reach in time. We wrote up the year-end send schedule that captures the last-3-days-of-December surge — that's where SMS earns its keep against mail's lead time.
Where the SMS math gets better (and worse)
The 7.3-cent figure isn't fixed. Two things move it.
It gets worse if you use unicode or write long. Drop an emoji into your appeal and the segment limit collapses from 160 GSM-7 characters to 70 unicode characters. A 175-character message that would have been 2 GSM-7 segments becomes 3 unicode segments — so your cost per contact jumps from $0.049 to about $0.0735, and your cost to raise $1 climbs proportionally. On a 20,000-send appeal that's the difference between $980 and $1,470 in send cost for the same message. Write in plain characters and keep it tight.
It gets better at volume. If your file is larger and you cross 50,000 segments in a calendar month, ReadySMS drops you to the Growth rate ($0.016 + $0.0045 = $0.0205/segment) automatically — you don't pick a plan or call anyone. On a big year-end push across multiple sends, that discount applies to the segments past 50K without you doing anything. The growth-tier crossover math walks through exactly where that kicks in if you want to plan your December volume around it.
There's also a compliance cost floor mail doesn't have. To text donors legally you register for A2P 10DLC — roughly $10/mo per brand and $20/mo per campaign in carrier fees, approved in a few days. That's a fixed ~$30/mo overhead, trivial against a $13,500 appeal but worth noting so it doesn't surprise your finance team. If you're deciding SMS vs email specifically, we ran that comparison in more depth in what it actually costs to raise $1 by text vs email.
The compliance line item mail donors never made you think about
Here's the honest tradeoff. Direct mail has no consent problem — you can mail anyone whose address you have. SMS is different: you can only text people who opted in, and every message has to honor STOP instantly. That's not a downside so much as a different discipline, and it's largely automated on our side. Inbound STOP is honored and propagated so an opted-out donor can't be messaged again across any campaign. Quiet-hours enforcement holds sends outside permitted local hours based on the recipient's area, which reduces TCPA exposure. And opt-in attestation is captured for bulk sends, building an audit trail.
For nonprofits, the exposure is real — TCPA violations run $500–$1,500 per text, and one careless blast to a non-consented list can cost more than your whole appeal raised. That's why the compliance automation matters more here than the per-segment price. We're not lawsuit-proof — the sender is always ultimately responsible — but the guardrails are doing the boring, expensive-to-get-wrong work by default. If you want the full picture, our nonprofit SMS compliance guide covers consent, opt-in structure, and 10DLC filing.
The practical takeaway
Don't replace channels. Sequence them. The model says:
- Keep mail as the workhorse for your higher-capacity, older file segments — it produces the most gross revenue and the largest gifts.
- Keep email for reach and reinforcement — it's nearly free, so let it do the volume work.
- Add SMS where mail can't compete: time-sensitive asks, year-end and Giving Tuesday closes, sustainer upgrades, and the segment of your file that lives on their phone. At ~7 cents to raise a dollar and money that lands in minutes, it fills the gap between mail's cost and email's weak conversion.
If you want to run these numbers against your own file — your response rates, your average gift, your list size — the cost calculator will do the segment math, and there are 2,500 free credits to test a small appeal before you commit a dollar. Model it against your real donors, not my round assumptions. That's the only version of this table that matters.