Why Cost Per Message Is the Wrong Number
Many businesses judge SMS by price per message and decide it looks cheap or expensive. Neither conclusion tells you much. Return on investment asks a better question: for every unit of currency spent, how much value came back? A message that costs a little more but produces a sale is far better than a cheaper one nobody acts on. Measuring ROI properly lets you compare SMS fairly against other channels and decide where your budget works hardest.
The Formula
The basic calculation is revenue attributed to the campaign, minus the total cost of the campaign, divided by the total cost, multiplied by 100 to give a percentage. A positive result means the campaign paid for itself, and a higher result means a stronger return. The arithmetic is easy. The real work is deciding what counts as revenue and what counts as cost.
A Worked Example With Illustrative Numbers
Suppose a clothing store sends a weekend sale message to 10,000 opted-in customers. Assume, for illustration only, that the messages cost Rs 0.20 each, so sending costs Rs 2,000. The platform fee allocated to this campaign is Rs 1,000, and a team member spent two hours on planning and copy, valued at Rs 600. The sale offered 15 percent off, and 120 orders were placed through the tracked link, with an average order value of Rs 1,800 before discount. Revenue before discount is 120 times Rs 1,800, which is Rs 216,000. The discount given is 15 percent of that, Rs 32,400, so net revenue is Rs 183,600.
The total cost is Rs 2,000 plus Rs 1,000 plus Rs 600, which is Rs 3,600. But a fair view also considers cost of goods. If the product margin is 40 percent of net revenue, the gross profit is Rs 73,440. Subtracting the campaign cost of Rs 3,600 leaves Rs 69,840 of profit, and dividing by the campaign cost gives a return of about 1,940 percent on profit. These numbers are invented to illustrate the method, not to suggest typical results, but they show why it matters to include discounts and margin: revenue alone would have overstated the real gain, and ignoring staff time would have understated the cost.
What Counts as Cost
Include sending costs, platform or subscription fees allocated to the campaign, registration costs, creative and staff time, and any discounts or incentives. Discounts are most often forgotten, and they reduce the margin on every sale a campaign produces. Including them gives a more honest picture than revenue alone.
Attributing Revenue Honestly
Attribution is the hardest part. The most reliable approach uses a unique tracked link or discount code in each campaign, so each click or redemption can be traced to the message. In-store sales can use unique codes or reply keywords. Direct attribution tends to understate impact, because some customers see the message and buy later through another route. To estimate the true effect, many businesses hold back a small random control group that does not receive the message, then compare purchases between the two groups. The difference is the incremental effect of the campaign.
Metrics That Explain the Result
ROI is the headline, but supporting metrics show why it is high or low. Delivery rate tells you whether messages arrived. Click-through rate shows how compelling the message was. Conversion rate shows how well the landing page turns clicks into orders. Opt-out rate shows whether frequency and relevance are sustainable. Revenue per message and customer lifetime value add depth, since a customer acquired through SMS may keep buying long after the first campaign.
Where ROI Usually Improves First
Automated flows such as cart recovery, renewal reminders, and win-back sequences often show some of the strongest returns because they reach customers at moments of high intent. Better segmentation raises returns by sending the right offer to the right people. Cleaning invalid numbers lowers wasted spend. Testing send times and offers reveals what your audience prefers. Review results after each campaign, and apply one improvement at a time so you can see what worked.
Common Mistakes
Common errors include counting gross revenue without subtracting discounts, ignoring staff time, crediting every sale in the campaign window to SMS, comparing campaigns with different audiences, and judging a long-term program by a single campaign. Another is measuring clicks only, which tells you about interest but not about profit.
Frequently Asked Questions
What is a good SMS ROI?
It depends on your margins, industry, and audience, so compare against your own past campaigns and against other channels, not a universal benchmark.
Can I measure ROI without special software?
Yes. Unique discount codes and a simple spreadsheet are enough to get started.
Should I include lifetime value?
For acquisition campaigns, yes. Looking only at the first purchase can undervalue campaigns that bring in loyal customers.
Conclusion
Calculating SMS ROI means looking past the price of a message to the profit it creates. Define costs fully, track revenue with unique links or codes, use a control group if you can, and support the headline number with delivery, click, conversion, and opt-out data. Businesses that measure carefully usually find that steady, data-guided improvements matter more than any single clever campaign.