Short answer: Cost per customer reached is your whole channel invoice, GST included, divided by the number of distinct people who demonstrably received the message. It is the only figure that survives a comparison between WhatsApp, SMS and voice, because each of the three bills you at a different point in the delivery funnel.
Why per-message prices do not compare
Put three published rate cards side by side and they look like they are measuring the same thing. They are not. Each channel sells a different unit, and the unit is doing most of the work.
WhatsApp sells you a template message. AiSensy’s published India card, read on 6 October 2026, prices a marketing template at ₹1.09 and a utility or authentication template at ₹0.145, described as “per delivered message”. Length does not matter — a 40-character notice and a 900-character one cost the same.
SMS sells you a segment. A GSM-7 message fits 160 characters in one segment, or 153 per segment once it splits across several; a Unicode (UCS-2) message fits 70, or 67 per segment. Hindi, Telugu and every other Indic script are UCS-2. So the identical notice costs one segment in English and three in Hindi.
Voice sells you a pulse. One published Indian card quotes a 28-second pulse at ₹0.30 for a 5,000-call slab, falling to ₹0.20 at 1,00,000 calls, and states “Charged only answered call”.
Three prices, three units. Dividing by messages sent compares nothing.
The three channels charge at three different points in the funnel
| Channel | Billing unit | What triggers the charge | Read signal available? | Published India rate, read 6 Oct 2026 |
|---|---|---|---|---|
| WhatsApp utility template | One template message | Delivery (AiSensy: “per delivered message”) | Yes — read status on the webhook | ₹0.145 |
| WhatsApp marketing template | One template message | Delivery | Yes | ₹1.09 |
| SMS | One segment, 160 GSM-7 / 70 UCS-2 characters | Submission to the operator | No — none in the protocol | ₹0.25 per segment, default slab |
| Bulk voice | One pulse, 28 seconds on the card below | Call answered | Not applicable; answer and duration only | ₹0.30 per answered call |
That table is the whole argument. WhatsApp will not charge you for a message it never delivered. SMS will charge you at submission and offers no way, at the protocol level, to learn whether anyone read it. Voice charges only when somebody picks up, but picking up and listening are not the same event.
The same 160-character notice, priced three ways
| Delivery method | Units per customer | Pre-GST | Including 18% GST |
|---|---|---|---|
| WhatsApp utility template | 1 message | ₹0.145 | ₹0.1711 |
| WhatsApp marketing template | 1 message | ₹1.09 | ₹1.2862 |
| SMS in English | 1 segment | ₹0.25 | ₹0.295 |
| SMS in Hindi | 3 segments | ₹0.75 | ₹0.885 |
| Bulk voice, one answered pulse | 1 pulse | ₹0.30 | ₹0.354 |
Translating the notice into Hindi triples the SMS bill and leaves the WhatsApp bill untouched. Teams that compare “₹0.25 SMS against ₹0.145 WhatsApp” and conclude the two are close are comparing an English segment with a template that carries any language at one price.
What “reached” has to mean before you divide
The denominator is where most channel comparisons quietly fall apart, so fix it before you calculate.
WhatsApp’s status webhook reports delivery and reading as separate events, so both denominators exist. SMS has no read receipt anywhere in the protocol — a delivery report tells you the handset accepted the message and nothing more. Voice gives you answer and duration, and an IVR keypress if you ask for one — which is why our IVR survey costing works in cost per completed survey rather than per call placed.
The honest consequence: there is no single signal all three channels can produce. So pick the strictest signal each channel genuinely emits, say which one you used, and never let a vendor’s word stand in for it. The voice card quoted above also states “Delivery Ratio:- 100%” and does not define the term anywhere on the page, which is a good reason to measure your own.
We publish no reach or engagement percentages here, and you should distrust any vendor that does, ourselves included. The fraction is a property of your contact list, not of the channel.
Notice what the chart does and does not say. The ratio between two channels never moves — SMS in Hindi stays about 5.17 times WhatsApp utility at every reached share, because the fraction cancels. What grows is the rupee gap. At full reach the difference is ₹0.605 per customer; at half reach, ₹1.21; at a quarter, ₹2.42. Waste is simply more expensive on the dearer channel.
A worked example: 25,000 contacts, one Hindi notice, one month
Take 25,000 contacts and one transactional notice in Hindi. Using AiSensy’s published Pro platform fee of ₹3,200 a month and its ₹0.145 utility rate:
- WhatsApp: ₹3,200 platform fee + 25,000 × ₹0.145 = ₹3,625 in messages, so ₹6,825 pre-GST and ₹8,053.50 including GST.
- SMS in Hindi: 25,000 × 3 segments × ₹0.25 = ₹18,750 pre-GST, ₹22,125 including GST. The same notice in English would be ₹6,250 pre-GST, ₹7,375 including GST.
- Bulk voice: 25,000 answered calls × ₹0.30 = ₹7,500 pre-GST, ₹8,850 including GST.
Now divide by a reach count rather than a send count. The numbers below are illustrative denominators, not claims about what any list achieves:
| Customers actually reached | SMS (Hindi) | Voice | |
|---|---|---|---|
| 25,000 | ₹0.3221 | ₹0.885 | ₹0.354 |
| 18,000 | ₹0.4474 | ₹1.2292 | ₹0.4917 |
| 12,500 | ₹0.6443 | ₹1.77 | ₹0.708 |
| 7,500 | ₹1.0738 | ₹2.95 | ₹1.18 |
At 25,000 reached, WhatsApp and voice are only about three paise apart — the ₹3,200 platform fee closes most of the gap the per-message rates suggest. That is the point: the fee is part of cost per customer reached, and it is invisible in a rate card comparison.
Where the platform fee hides
A fixed monthly fee behaves like a per-customer charge that shrinks as you send more. Against AiSensy’s published monthly fees, and at 25,000 contacts, the fee adds ₹0.06 per contact on Basic (₹1,500), ₹0.128 on Pro (₹3,200), ₹0.364 on Premium (₹9,100) and ₹1.80 on Unlimited (₹45,000). Put another way, the Pro fee equals 22,069 utility messages before you have sent one.
So a low per-message rate on a high fixed fee can lose to the opposite combination, and which wins depends entirely on your volume. Our own WhatsApp Business API pricing guide works through the layers of that bill, and SMS vs WhatsApp vs voice takes the channel comparison further.
Volume slabs move the per-unit number, not the method
Both the SMS and voice cards, read on 6 October 2026, are slab-priced on money paid up front. Fast2SMS lists ₹0.25 per SMS as the default, falling through ₹0.21, ₹0.19, ₹0.17, ₹0.15 and ₹0.13 to ₹0.11 on a top-up of ₹6,00,000 or more — 56% below the default. For the three-segment Hindi notice that is ₹0.75 per customer at the default and ₹0.33 at the top slab. The voice card runs ₹0.30 down to ₹0.20 between 5,000 and 1,00,000 calls, and pulse rounding does more damage to that figure than the slab does — bulk voice call pricing sets out why.
Slabs change the numerator. They do not change the fact that you must divide by people, not messages.
How to work it out for your own list
Pull one month of invoices per channel, GST included. Pull the delivery, read or answer counts from your provider’s reports or webhooks. Deduplicate the recipients so one person counts once however many notices they received. Divide, and label each figure with the signal you used. Do that once and the channel argument usually settles itself. If you would like the measurement set up alongside the sending, start at our pricing page.
Frequently asked questions
Is cost per customer reached the same as cost per conversation? No. A conversation-based figure counts billable windows; this counts people. If one customer receives three notices in a month, that is three charges and one customer reached.
Should GST be inside the number? Yes, if you are not reclaiming input tax credit. Telecommunication services sit under SAC 9984 at 18% GST, and the voice card we read prints GST on every slab. Keep it consistent across channels or the comparison breaks.
Which denominator should I use for SMS, given there is no read receipt? Use delivery reports and label the figure as cost per delivered SMS. It is not comparable with a WhatsApp cost-per-read figure, and saying so is more useful than pretending otherwise.
Does WhatsApp charge for messages that fail? AiSensy’s card describes its rates as per delivered message. Meta’s own developer pricing page, read on 6 October 2026, did not state the trigger explicitly either way, so confirm it against your own invoice rather than assuming.
Are utility and service messages free inside the 24-hour window? Two live sources disagree, and we are not going to reconcile them for you. Meta’s developer pricing page, read 6 October 2026, states “Utility templates delivered within an open customer service window are free” and “Effective November 1, 2024 – Service conversations are now free for all businesses.” AiSensy’s pricing page, read the same day, states that from 1 October 2026 utility messages inside the window are chargeable and that service messages cost ₹0.145 after 1,000 free per number per month, attributing the change to Meta. Check your own invoice for October.
Does a cheaper channel always win on this number? No, and that is the useful part. Because the reached fraction cancels out of a ratio, a channel only wins by being cheaper per unit, needing fewer units per customer, or reaching a materially different set of people.
Verification note
Every figure above was read from a live source on 6 October 2026 and no figure was carried over from an earlier post. All arithmetic was computed rather than estimated. Rates change without notice — re-check before you budget.
Figures we could not verify on 6 October 2026, and therefore did not use: Meta’s own India INR list rate card (the rate table on whatsappbusiness.com loads dynamically and could not be read); Interakt’s rate card, which returned HTTP 403 that day, so none of its figures were reused; and any reach, delivery or read percentage, which no primary source publishes.
Disclosure: xreach51 sells WhatsApp, SMS, voice and IVR messaging in India, so AiSensy, Fast2SMS and the voice provider named above are competitors of ours. We have published their figures with dates so you can check them yourself, and we have not published ours.
Sources
- Meta, Pricing on the WhatsApp Business Platform,
developers.facebook.com/docs/whatsapp/pricing— read 6 October 2026 - AiSensy, WhatsApp Business API Pricing,
aisensy.com/pricing/— read 6 October 2026 - AiSensy, WhatsApp service message pricing update, October 1 2026 — read 6 October 2026
- Fast2SMS, Bulk SMS Pricing,
fast2sms.com/bulk-sms-pricing— read 6 October 2026 - Bulk SMS Plans, Bulk Voice Call,
bulksmsplans.com/voice-calls.html— read 6 October 2026 - Twilio, What is the SMS character limit? — read 6 October 2026
- GST Council, An Overview of Telecom Services — GST perspective (SAC 9984, 18%) — read 6 October 2026