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OTP cost: SMS vs WhatsApp
At ₹0.25 an SMS and ₹0.25 a WhatsApp authentication message, 1,000 people logging in 1.3 times cost ₹374 by SMS and ₹343 by WhatsApp, ex-GST. At the same unit price WhatsApp wins on resends: fewer codes go missing. Email OTP is cheaper still, and employee codes or delegate PINs cost nothing per login.
SMS vs WhatsApp
WhatsApp is cheaper by ₹31
SMS ₹374 · WhatsApp ₹343 for 1,300 logins, ex-GST
At these rates WhatsApp is cheaper by ₹31, mostly because fewer codes need resending. Keep SMS as the fallback for people not on WhatsApp.
- SMS per login
- ₹0.291,495 messages
- WhatsApp per login
- ₹0.261,297 + 75 fallback SMS
- Cheapest OTP of all
- Email: ₹72+₹13 GST
| SMS1,495 messages · ₹0.29 per login | ₹374 |
|---|---|
| WhatsApp (SMS fallback)1,372 messages · ₹0.26 per login | ₹343 |
| Email1,430 messages · ₹0.06 per login | ₹72 |
| Employee code or delegate PINno message sent; works where you issue codes or PINs | ₹0 |
| Logins1,000 people × 1.3 | 1,300 |
| SMS price where WhatsApp becomes cheaper | ₹0.23 |
Estimate. Messages are billed on actuals, GST extra; Meta and DLT operators change rates, so every rate is editable.
How we calculate
- Logins
people × logins per personA second phone, a reinstall or being logged out all need a new code.
- SMS cost
logins × (1 + SMS resend rate) × SMS rateEvery resend is another paid message.
- WhatsApp cost
logins on WhatsApp × (1 + WhatsApp resend rate) × WhatsApp rate + the rest by SMSPeople not on WhatsApp get the code by SMS.
- Break-even SMS price
WhatsApp messages × WhatsApp rate ÷ (SMS messages − fallback SMS)Above this SMS price, WhatsApp OTP is the cheaper channel.
Assumptions
- Default rates are Sociana’s on-actuals prices, ex-GST: SMS ₹0.25, WhatsApp utility and authentication ₹0.25, email ₹0.05, from the price list dated 23 Oct 2026.
- Meta’s India authentication rate was about ₹0.115 per message in 2026 before GST and the provider fee. WhatsApp OTP runs through the organisation’s connected WhatsApp provider account, so enter that account’s rate if you have one.
- Resend rates are planning assumptions; your delivery logs give the real ones.
- SMS needs DLT registration of the sender and template in India.
Prices as of 23 Oct 2026.
Worked examples
| Scenario | Result | In one line |
|---|---|---|
| Conference, 1,000 delegates | WhatsApp is cheaper by ₹31 SMS vs WhatsApp | OTP cost: 1,000 people, 1,300 logins. SMS ₹374, WhatsApp ₹343, email ₹72 (ex-GST). Cheapest of all: Email. SMS break-even for WhatsApp: ₹0.23 per SMS. |
| Dealer meet, 3,000 partners, own WhatsApp account | WhatsApp is cheaper by ₹622 SMS vs WhatsApp | OTP cost: 3,000 people, 4,500 logins. SMS ₹1,350, WhatsApp ₹728, email ₹248 (ex-GST). Cheapest of all: Email. SMS break-even for WhatsApp: ₹0.13 per SMS. |
Example inputs are illustrative, not client data. Tap “Start from” above to load either one.
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Questions about this calculator
Is WhatsApp OTP cheaper than SMS in India?
Usually, by a little. At ₹0.25 an SMS and ₹0.25 a WhatsApp message the unit prices tie, so the difference comes from resends: SMS codes go missing more often. If your SMS rate is lower or SMS resends are rare, SMS can come out cheaper. On your own WhatsApp provider account at about ₹0.15, WhatsApp is cheaper still.
How much does OTP login cost for an event app?
Very little either way: for 1,000 people it is a few hundred rupees. Choose the channel your audience receives reliably; the cost difference rarely decides it.
Can people log in without an OTP?
Yes. Employee-code login and delegate ID with PIN need no message at all, which suits closed audiences such as employees or registered delegates.
What about international participants?
Email OTP is the simple answer for people without an Indian mobile number; one occasion let international partners log in by email while everyone else used phone OTP.