Klaviyo SMS Marketing: Pricing, Limits, and Two Clocks Inside One Platform

Klaviyo SMS marketing is Klaviyo’s text messaging product, sold as a prepaid monthly Mobile Messaging plan beside its email plan and, since mid-2026, priced in dollars per message rather than credits. Email and SMS share one platform, but Klaviyo applies its frequency limit, Smart Sending, to each channel separately.

This guide answers the questions Google shows for the term (can Klaviyo do SMS, what it charges, Klaviyo or Postscript, and whether SMS marketing is legal) from Klaviyo’s and Postscript’s own pages as served on October 5, 2026. Klaviyo’s help center and its product page disagree in places, because the pricing model changed in July; where they do, this guide follows the newer help article and says so. Relvino is a competitor to both vendors, so read it as informed but interested.

Can Klaviyo do SMS?

Yes. The product page calls it “Text message marketing built for smarter sends” and says SMS is “available in 20+ countries,” listing the US, Canada, the UK, Australia, New Zealand and a set of European countries and Mexico. The free plan includes “$5 of mobile messages/month” alongside 250 profiles and 500 emails, per the pricing page. Paid sending runs on a separate plan: Klaviyo’s billing article lists “Profile and Email” and “Mobile Messaging (SMS, MMS, Whatsapp, & other mobile channels)” as separate products.

How much Klaviyo charges for SMS

The model changed this summer, and not for everyone on the same day. Klaviyo’s FAQ on the change: “Mobile per-message pricing replaces Klaviyo’s credit-based system with clear, dollar-based rates for mobile messaging.” It took effect “immediately as of July 13, 2026” for new customers and free mobile plans; existing paid subscriptions move at their next billing cycle after August 13, 2026. The plan is still bought in advance: “You still purchase your plan upfront (the same commit model as today), but your plan is now denominated as a dollar amount (for example, a “$115 Mobile Messaging plan”) rather than a set number of credits.” Larger plans pay less per message, and Klaviyo says it is “adding over 70 new plan tiers with smaller gaps between them”.

The rate itself is “the dollar cost of a single text message (SMS or MMS) sent to a single recipient,” and it varies “by channel (SMS, MMS, WhatsApp, or RCS), by country, and, for US and Canada SMS, by number type (toll-free vs. short code).” The help article sends readers to their own account for exact rates, and the one public figure on the pages read is the product page’s calculator, whose default state reads 1,000 messages for $15 for United States toll-free; it is an interactive widget, so treat it as an example rather than a quote for a given plan. The same page’s FAQ still says messages “cost a different number of credits, depending on the country of the message recipient”; that is the model the July help article replaces, and this guide follows the help article.

Five billing rules from the help center change what a month costs in practice:

• Unused spend expires. “You have a set amount of plan spend each month, and unused spend doesn’t roll over.”
• Carrier fees are inside the rate. “The rate shown for each message type and region is the all-in cost,” the help center says, and “there are no separate carrier fee line items on your invoice.”
• Long messages bill per segment. “SMS allows up to 160 characters, or 70 characters when there’s an emoji or special character.” A longer send is split, and a header on each segment “brings the effective limit for a split SMS down to 153 characters per segment,” with each segment billed. MMS allows up to 1,600 characters with an image or GIF under 600 KB.
• Skipped messages are free; failed ones are not. The billing table lists “Skipped messages (smart sending, no SMS consent, etc.)” as not billable and “Failed to deliver messages (message blocked, device disconnected, etc.)” as billable.
• Flexible overage is for larger plans. “Flex is available as a billing preference for Mobile Messaging subscription plans of $490 per month or more.”

One platform, two clocks

The case Klaviyo makes for SMS is the platform. Its product page asks “Why is it better to have email and SMS in the same platform?” and answers that brands can “better personalize and segment campaigns with sms, email, mobile push, and reviews in one centralized place,” under the heading “One customer view.” Klaviyo’s help center shows one working example of the shared profile: a flow that sends both email and SMS can split on a shopper’s SMS consent.

The control that decides how much a shopper hears from the brand is not shared. Klaviyo’s text message settings article: “Smart Sending allows you to limit the number of SMS messages someone will receive in a given period of time,” with a default window of 24 hours, and then: “SMS Smart Sending and email Smart Sending are treated separately. For instance, after you send an email, you can still send an SMS the same day when Smart Sending is on. The SMS Smart Sending window only applies to SMS, and the email window only applies to emails.”

Quiet hours are an SMS setting, and even within SMS the timezone source differs by sending type: “currently, timezone from a profile’s location property is used in Campaigns quiet hours only. At this time, flows quiet hours uses only the profile’s phone number area code.”

So the platform shares the data and keeps two clocks. A shopper who receives a cart email at noon can receive the cart text the same afternoon, because the help center treats the two windows separately. That is the practical meaning of a single platform in Klaviyo’s own help center: it removes the integration between two vendors, not the second frequency limit. The Klaviyo vs Attentive guide covers the two-vendor setup.

Klaviyo SMS or Postscript?

Postscript prices the other way round. Its pricing page lists a Starter plan at $0 a month with a $49 monthly minimum spend at $0.009 per SMS and $0.045 per MMS, Growth at $100 a month at $0.008 and $0.03, and Professional at $500 a month at $0.007 and $0.024, each “+ Carrier fees,” with average US carrier fees stated as $0.0033 per SMS. It positions itself against prepaid plans: “Pay after you send. No prepaid balances, expiring credits, overages, or auto-upgrades, and carrier fees pass through at cost on their own line - so you know what you are paying for.” Its page describes plans covering “SMS, RCS and Email.”

Klaviyo’s comparison page makes the platform argument about its rival: “With Klaviyo CRM, you can go beyond SMS, combining it with email and other channels for more powerful, personalized campaigns in a single platform. With Postscript, you can’t.” That is Klaviyo’s claim about a competitor, and Postscript’s own page lists email among its plans, so it is reported here as an argument, not a fact.

• How it is billed · Klaviyo SMS: Prepaid monthly dollar plan; unused spend does not roll over · Postscript: Monthly plan fee or minimum spend plus per-message rates, billed after sending · Relvino: See /pricing
• Carrier fees · Klaviyo SMS: Included in the rate · Postscript: Passed through on their own line · Relvino: See /pricing
• Published US SMS rate · Klaviyo SMS: In-account only; calculator default of 1,000 toll-free messages for $15 · Postscript: $0.009, $0.008 or $0.007 per SMS by plan, plus carrier fees · Relvino: See /pricing
• Email in the same product · Klaviyo SMS: Yes, separate plan line · Postscript: Listed on its pricing page · Relvino: Yes, plus pop-ups
• Frequency limit across email and SMS · Klaviyo SMS: Smart Sending applied to each channel separately · Postscript: Not described on the pages read · Relvino: One decision per shopper covering every channel

Is SMS marketing legal in the USA?

Yes, with consent, and the rules are stricter than for email. Klaviyo’s compliance article: “it is also illegal to send unsolicited text messages to people without their consent, and the fines can be heavy,” with fines from “$500 per violation to $1,500 per willful violation.” The TCPA “prohibits any telephone solicitation (including text messages) anytime before 8 am and after 9 pm in the recipient’s time zone,” and some states are stricter. Email consent does not carry over: “Consent for email does not count as consent for SMS and vice versa.” Klaviyo also notes that it “cannot provide legal advice regarding US SMS compliance laws,” and neither can this guide.

When Klaviyo SMS is the right call

For a brand already on Klaviyo email that wants SMS without a second vendor, the shared profile is worth having, and the prepaid plan is predictable for a steady sending volume. For a brand whose SMS volume swings by season, the no-rollover rule and the tier choice matter more than the rate. And for a brand that wants one decision per shopper across channels, the comparison to read is Klaviyo vs Relvino; Relvino decides per shopper, in about 80ms, whether to send at all and on which of email, SMS or a pop-up. Related reading: Postscript alternatives, Attentive pricing and Klaviyo pricing.

Frequently asked questions

Can Klaviyo do SMS?

Yes. SMS, MMS and other mobile channels are sold as a Mobile Messaging plan that sits beside the email plan, in more than 20 countries. A store that already uses Klaviyo email turns it on from the same account, collects SMS consent separately from email consent, and buys a monthly mobile plan sized to its expected sending.

How much does Klaviyo charge for SMS messages?

Since July 13, 2026 Klaviyo charges a dollar rate per message that depends on channel, country and, in the US and Canada, toll-free or short code number type; the rates are visible inside the account. The plan is bought upfront each month as a dollar amount. To estimate it, multiply expected monthly messages by the number of segments each one uses, then add MMS at its higher rate.

What’s better, Klaviyo SMS or Postscript?

It depends on how steady the sending is and where email lives. Klaviyo suits a brand that wants SMS on the same profile as its Klaviyo email and sends a predictable monthly volume. Postscript suits a brand that wants to pay after sending, see carrier fees on their own line, and run SMS as its own program.

How many characters can a Klaviyo SMS have?

160 characters for a plain SMS, or 70 when the message contains an emoji or special character. Longer messages are split into segments of 153 characters and each segment is billed, even though the shopper sees one message. MMS allows up to 1,600 characters with an image or GIF under 600 KB. Klaviyo’s formula for a send is rate times recipients times message segments, so a 200-character text to 1,000 people bills 2,000 segments.

Is SMS marketing legal in the USA?

Yes, with written consent, most commonly collected through an SMS opt-in, and within quiet hours: the TCPA bars marketing texts before 8 am and after 9 pm in the recipient’s time zone, and some states are stricter. Consent for email does not count for SMS, and buying a list does not create consent. For abandoned-cart texts in the US, Klaviyo says double opt-in is a carrier requirement, and opt-outs should be honored within 10 days. Brands should confirm the details with counsel.

How long does it take to migrate from Klaviyo SMS to Relvino?

About 30 minutes for the technical cutover: connect the Shopify store, point the sending domain, connect SMS, and shopper data, including consent status, ingests automatically. There are no SMS flows to rebuild; email, SMS and pop-ups are decided per shopper inside guardrails the brand sets. Revenue is measured in a 14-day pilot beside the existing setup.