Klaviyo SMS Marketing: Is It Worth It? (We've Sent 2M+ Messages)

"Should we add SMS?" is the question we get asked most by eCommerce brands. And our answer is always the same: probably yes, but not the way you think.

Most brands approach SMS like email with fewer characters. Blast the whole list, send 3x per week, slap a discount code on everything. Then they wonder why their unsubscribe rate is 5% per campaign and their phone bill is through the roof.

We've sent over 2 million SMS messages through Klaviyo across 80+ eCommerce brands. Here's what actually works, what doesn't, what it costs, and — most importantly — whether the ROI justifies it for your store.

The Real ROI Numbers (Not the Cherry-Picked Ones)

Let's start with what everyone wants to know: does SMS make money?

Across our 80+ brands with SMS enabled, here are the average numbers:

| Metric | Average | Top 25% | Bottom 25% | |---|---|---|---| | Revenue per SMS message sent | $0.18 | $0.35 | $0.06 | | Revenue per SMS subscriber (monthly) | $1.80 | $3.50 | $0.60 | | SMS revenue as % of total email+SMS revenue | 14% | 22% | 5% | | ROI on SMS spend | 28x | 45x | 8x | | Cost per SMS sent (US) | $0.01-$0.015 | — | — | | Cost per SMS sent (Canada) | $0.02-$0.03 | — | — |

Even at the bottom 25th percentile — 8x ROI — SMS is profitable. The question isn't whether it works. It's how much it works for your specific situation.

The math for a typical brand: 10,000 SMS subscribers. Send 4 messages per month (2 campaigns + 2 flow triggers). Cost: ~$600/month. Revenue generated: ~$7,200/month. That's 12x ROI.

When SMS Prints Money

SMS works best under specific conditions. Here's where we see the strongest returns:

1. Abandoned Cart SMS (The Money Flow)

Adding one SMS to your abandoned cart flow — sent 2 hours after abandonment, before the second email — increases cart recovery by 15-25%. The SMS click-through rate on abandoned cart messages averages 12-18%. Compare that to email's 3-5% CTR.

Why it works: People miss emails. They don't miss texts. And the abandoned cart SMS arrives during a high-intent moment — they were literally about to buy.

Revenue impact: For a brand with 1,000 abandoned checkouts/month and $70 AOV, adding abandoned cart SMS recovers an additional $1,200-$2,500/month.

2. Flash Sales and Limited Drops

SMS is unbeatable for time-sensitive offers. When you have a 24-hour sale or a limited product drop, email might not be opened in time. SMS gets read within 3 minutes on average.

Our data: Flash sale campaigns sent via SMS generate 3-5x more revenue per recipient than the same offer sent via email only. The key: scarcity + immediacy + direct link to the product page.

3. VIP-Only Offers

Your top customers — the VIP segment — respond incredibly well to SMS. It feels personal. "Hey [name], we're giving you first access to our new collection before anyone else. Shop here: [link]." Open rate: 95%+. Click rate: 20-30%.

4. Back in Stock / Price Drop Alerts

When a specific product is back in stock or drops in price, the person who browsed that product wants to know NOW. SMS delivers that notification instantly. RPR on these messages: $0.40-$0.80 per SMS sent (massively higher than campaign averages).

5. Post-Purchase Updates

Order confirmation, shipping updates, delivery notifications — these aren't marketing messages, but they build the habit of reading your texts. And you can weave in soft upsells: "Your order just shipped! While you wait, check out what's new: [link]."

When SMS Doesn't Work (Or Isn't Worth It)

Here's where we tell you NOT to use SMS. Because sending bad texts is worse than sending no texts.

1. Weekly "Content" Messages

Nobody wants a text that says "Check out our latest blog post" or "5 tips for better skincare." That's email content. SMS is for action — buy this, claim this, this is expiring. If there's no urgency, don't text.

2. More Than 4-6 Campaigns Per Month

We've tested send frequency extensively. Here's the unsubscribe rate data by frequency:

| SMS Campaigns Per Month | Avg Unsubscribe Rate Per Campaign | |---|---| | 2 | 0.3% | | 4 | 0.5% | | 6 | 1.2% | | 8 | 2.8% | | 10+ | 5.0%+ |

At 8+ SMS campaigns per month, you're losing subscribers faster than you're monetizing them. The sweet spot for most brands is 2-4 campaigns per month, plus flow-triggered messages.

3. Brands With Low AOV and Low Margins

If your AOV is $20 and your margin is 30%, each SMS costs you $0.01-$0.015 to send. You need a pretty high conversion rate to make the math work on campaigns. Flows still work because they're triggered by high-intent behavior, but campaign SMS has diminishing returns below $40 AOV.

4. International Audiences

SMS costs vary dramatically by country. Sending to the UK is $0.05+ per message. Australia is $0.06+. Some countries have strict opt-in laws that make SMS marketing nearly impossible. If more than 40% of your customers are outside the US and Canada, the ROI math gets tough.

5. Without Proper Consent

This is a compliance issue, not a strategy one. But we're mentioning it because we see it in audits: brands adding SMS to flows for people who only opted into email. That's a TCPA violation. Fines start at $500 per unsolicited text message. Don't do it.

Compliance: The Rules You Can't Ignore

SMS marketing is regulated more tightly than email. Here's what you need to know:

TCPA (US)

• You need express written consent before sending marketing SMS
• Consent must be separate from email consent (can't bundle them)
• Every message must include opt-out instructions ("Reply STOP to unsubscribe")
• You can't send between 9 PM and 8 AM in the recipient's time zone
• Violations: $500-$1,500 per message. Class action lawsuits are common.

CASL (Canada)

• Similar to TCPA but stricter
• Consent must be explicit and documented
• Commercial messages need clear identification of the sender
• Opt-out must be processed within 10 business days

How Klaviyo Handles This

Klaviyo has built-in compliance tools:

• Separate SMS consent collection — their signup forms have a separate SMS checkbox
• Quiet hours — you can set quiet hours so messages don't send late at night
• Auto STOP handling — when someone replies STOP, they're automatically suppressed
• Consent tracking — every subscriber's SMS consent is logged with timestamp and source

Our recommendation: Use Klaviyo's built-in SMS consent collection on your popup forms. Add a checkbox that says "I agree to receive marketing text messages from [Brand]. Msg frequency varies. Msg & data rates may apply. Reply STOP to cancel." This language is TCPA-compliant.

The Exact SMS Setup We Build for Every Client

Step 1: Enable SMS in Klaviyo

Go to Settings > SMS. Set your sender number (toll-free for most brands, short code for high-volume senders). Apply for your number through Klaviyo — they handle carrier registration.

Toll-free vs. Short code:

• Toll-free: Free to set up, sends up to 10 messages/second, fine for most brands
• Short code: $500-$1,000/month, sends up to 100 messages/second, needed for lists over 50K+

Step 2: Add SMS to Your Signup Popup

Update your popup to collect phone numbers. In Klaviyo, go to Signup Forms and edit your popup to include:

• Phone number field
• SMS consent checkbox (separate from email)
• Compliance language

Incentive: Offering an additional incentive for SMS signup (e.g., "Get 15% off via email OR 20% off when you join our text list") increases SMS opt-in rates from 5% to 15-20% of popup submissions.

Step 3: Add SMS to Key Flows

The flows where SMS adds the most value:

Abandoned Cart Flow: Add one SMS 2 hours after abandonment (before Email 2). Message: "Hey [first name]! You left items in your cart at [brand]. Complete your order before they're gone: [link]"

Welcome Flow: Add one SMS 30 minutes after signup (before Email 1 if they opted into SMS). Message: "Welcome to [brand]! Here's your [X]% off code: [code]. Shop now: [link]"

Back in Stock Flow: SMS instead of (or in addition to) email. Message: "[Product name] is back in stock! Grab yours before it sells out again: [link]"

VIP Exclusive Flow: SMS for early access. Message: "[First name], you're getting first access to our [sale/launch]. Shop 24 hours before everyone else: [link]"

Step 4: Set Up SMS Campaigns (Sparingly)

Campaign SMS should be reserved for:

• Flash sales (24-48 hour events)
• Product launches
• BFCM and major shopping events
• VIP-only offers
• Restock announcements

Frequency: 2-4 per month. No more.

Timing: Tuesday-Thursday, 10 AM - 2 PM local time performs best. Avoid Mondays (people are in work mode) and weekends (people don't want to shop from texts on Saturday morning).

Step 5: Track and Optimize

In Klaviyo, go to Analytics > SMS Performance. Track:

• Revenue per SMS sent (target: $0.15+)
• Click rate (target: 8%+)
• Unsubscribe rate per campaign (target: under 1%)
• SMS list growth rate (target: 10-15% of email list within 6 months)

SMS Message Templates That Convert

Here are actual message formats we use (with brand names removed):

Abandoned Cart:

Hey [first name]! You left something in your cart. Complete your order before it sells out: [link] Reply STOP to opt out

Flash Sale:

🚨 24-HOUR FLASH SALE 🚨 [X]% off everything at [brand]. Today only. Shop now: [link] Reply STOP to opt out

Product Launch:

[First name], it's here. Our new [product] just dropped and stock is limited. Be the first to grab yours: [link] Reply STOP to opt out

VIP Early Access:

[First name], you're a VIP. Get 24-hour early access to our [event]. Shop before anyone else: [link] Reply STOP to opt out

Back in Stock:

[Product name] is BACK. Last time it sold out in 3 days. Grab yours now: [link] Reply STOP to opt out

Key rules for SMS copy:

• Keep it under 160 characters (one segment = lower cost)
• Include the brand name
• Include a direct link (use Klaviyo's URL shortener)
• Always include opt-out language
• Use the recipient's first name when possible
• One CTA only — don't give them choices

The Cost Breakdown (What You'll Actually Spend)

Here's what SMS costs in practice for a mid-size brand:

Assumptions: 10,000 SMS subscribers, 4 campaigns/month, flows sending ~2,000 triggered messages/month.

| Item | Monthly Cost | |---|---| | Klaviyo SMS plan (included with email plan) | $0 (bundled) | | Campaign messages: 40,000 (10K x 4) | $400-$600 | | Flow messages: 2,000 triggered | $20-$30 | | Total monthly SMS cost | $420-$630 |

Expected revenue: $7,000-$12,000/month from SMS.

Net ROI: 11-19x on SMS spend alone.

Should YOU Add SMS? The Decision Framework

Add SMS if:

• [x] Your email list is 5,000+ subscribers
• [x] Your AOV is $40+ (US) or $50+ (international)
• [x] You have at least 3 active Klaviyo flows
• [x] You can commit to NOT over-sending (4-6 campaigns/month max)
• [x] You sell time-sensitive products (limited editions, seasonal, consumable)

Wait on SMS if:

• [ ] Your email list is under 2,000
• [ ] Your Klaviyo flows aren't built yet (fix email first)
• [ ] You don't have a TCPA-compliant consent collection process
• [ ] Your AOV is under $30 and margins are thin
• [ ] Most of your customers are outside North America

The Bottom Line

SMS isn't a replacement for email. It's a multiplier. The best Klaviyo accounts use email for the heavy lifting (flows, campaigns, content) and SMS for the high-impact moments (abandoned carts, flash sales, VIP offers, restocks).

We've sent 2M+ messages and the data is clear: SMS adds 12-22% to total email+SMS revenue when done right. And it destroys your list when done wrong.

If you want us to evaluate whether SMS makes sense for your brand and set it up properly inside your Klaviyo account, that's exactly what we do in our free audit.

Book your free Klaviyo + SMS audit.

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Mark Cijo is the founder of GOSH Digital, a Klaviyo Gold Partner agency that's driven $23M+ in revenue for 150+ eCommerce brands. He's personally managed SMS programs that have sent 2M+ messages — and learned what NOT to do the hard way.