WhatsApp Broadcast vs Bulk SMS: Which Is Better for BD Brands?

The Pohela Boishakh sale starts tomorrow and a clothing brand in Sylhet has 12,000 customer numbers. The marketing lead wants to send the offer on WhatsApp, with a photo of the new collection. The owner wants SMS, "because everyone reads SMS". They are both partly right.

WhatsApp broadcasts and bulk SMS are not rivals so much as tools for different jobs. This guide compares them on the things that matter to a Bangladeshi brand (reach, cost, approval, replies and rules) and shows which one to use for each kind of message.

What is the difference between a WhatsApp broadcast and bulk SMS?

A WhatsApp broadcast sends an approved template to opted-in WhatsApp users, with media, buttons and a reply channel. Bulk SMS sends plain text to any mobile number through an SMS gateway, usually one-way.

Which channel reaches more customers?

Bulk SMS reaches more customers, because it works on every phone, with or without WhatsApp or mobile data. WhatsApp reaches only customers who use WhatsApp on that number and are online to receive it.

In practice, most Bangladeshi online shoppers who order through Facebook and WhatsApp can be reached on WhatsApp. The customers you miss tend to be older buyers, people on feature phones, customers who ordered with a different number from their WhatsApp number, and anyone without data that day. For order-critical messages like "the rider is coming today", that missing group is exactly who you cannot afford to miss.

Which one costs less?

Neither is always cheaper. WhatsApp charges one rate per delivered template regardless of length, while SMS charges per segment, so long messages and Bangla text change the maths.

How to calculate the cost of a WhatsApp broadcast

Delivered messages × Meta's Bangladesh rate for the template category. Marketing templates cost more than utility templates. Bangladesh has had its own rates on Meta's rate card since 1 October 2026, and rates change by quarter, so take the current figure from Meta's pricing page. Meta charges only for delivered messages.

How to calculate the cost of bulk SMS

Recipients × segments per message × your gateway's rate per segment. Masked SMS is usually priced higher than non-masked. The segment count is the trap:

That medium Bangla message costs three times a short one. One stray Bangla character or emoji in an English message can also switch the whole message to Unicode and its 70-character limit.

Say you send a 140-character Bangla offer to 10,000 people: that is 30,000 SMS segments. Do the same calculation with your real rates and compare it with 10,000 marketing templates on WhatsApp.

Which channel gets more response?

WhatsApp is built for response; SMS is built for notice. A WhatsApp broadcast can have "Show me" or "Order now" buttons, and the reply lands in a chat where your team or a bot can sell. You also see who read the message.

SMS has no buttons. Masked SMS usually cannot be replied to, so the customer has to call, click a link or open WhatsApp. That is fine for alerts and reminders, and weak for offers that need a conversation.

Which should you use for each message?

Use WhatsApp for anything that should start a conversation, and SMS for anything that must reach every phone. Here is how that works out for a typical online shop:

How do you use WhatsApp and SMS together?

Use WhatsApp first and SMS as the fallback, and never send the same offer on both channels to the same person.

1. Keep a separate opt-in per channel. Yes to WhatsApp offers does not mean yes to SMS offers.
2. Send on WhatsApp first. To opted-in customers who use WhatsApp.
3. Fall back to SMS. For customers without WhatsApp, and for important messages that failed to deliver on WhatsApp.
4. Do not double up on offers. Two copies of the same promotion feel like spam and raise blocks on WhatsApp.
5. Use both for delivery day. The message that saves a parcel is worth sending twice.

What rules apply to each channel?

Both channels need consent, but the rules come from different places. WhatsApp rules come from Meta; SMS rules come from Bangladesh's telecom regulator and your gateway.

• WhatsApp: opt-in before you message, an approved template for every broadcast, a messaging limit that starts at 250 customers a day for new business portfolios, and per-person caps on marketing messages. See how to send a WhatsApp broadcast without getting blocked.
• SMS: gateways operate under BTRC licensing, masks (brand sender IDs) are registered through the gateway, and gateways apply rules on promotional content and sending. These rules change, so ask your gateway for the current version in writing. The glossary entry on masking SMS explains sender IDs.

How does SaleMag handle WhatsApp broadcasts and bulk SMS?

SaleMag sends WhatsApp broadcasts, bulk SMS and email campaigns from one campaigns screen, using one contact list. Each contact has separate WhatsApp, SMS and email opt-in flags, and contacts without opt-in for the chosen channel are skipped.

For SMS, SaleMag connects to 15 providers through your own account, including five Bangladeshi gateways: SMSBD, REVE SMS, BulkSMS BD, SMS.BD and MimSMS. You set the sender ID or mask per gateway, the composer shows the character count, and delivery reports come back from most providers. SMS is outbound only: replies do not reach the SaleMag inbox.

A practical fallback: export a WhatsApp campaign's failed recipients to CSV, then upload that list as the audience of an SMS campaign.

Next steps

Sort your last month's customer messages into "should start a conversation" and "must reach every phone". Send the first group on WhatsApp and the second by SMS. To run both from one list, start free with SaleMag or see pricing.