When evaluating AI voice assistants, understanding the true cost is crucial. Unlike traditional IVR systems with fixed per-seat licensing, modern AI voice platforms use usage-based pricing across multiple components. This guide breaks down every cost factor so you can budget accurately and maximize ROI.
The Four Cost Components
Every AI voice call involves four billable components:
Total Cost = STT + LLM + TTS + Telephony
| Component | Purpose | Cost Range |
|---|---|---|
| STT (Speech-to-Text) | Converts caller speech to text | ₹0.35 - ₹1.50/min |
| LLM (Language Model) | Processes intent, generates response | ₹0.04 - ₹1.00/min |
| TTS (Text-to-Speech) | Converts response to speech | ₹0.00 - ₹12.60/min |
| Telephony | Phone number, call routing | ₹0.50 - ₹2.00/min |
The total typically ranges from ₹2 to ₹15 per minute depending on your provider choices.
STT (Speech-to-Text) Pricing
STT converts the caller's voice into text for the LLM to process. Costs vary significantly based on language support and accuracy requirements.
STT Provider Comparison
| Provider | Cost/min | Best Languages | Accuracy | Latency |
|---|---|---|---|---|
| Deepgram Nova-2 | ~₹0.35 | English, Spanish | Excellent | ~150ms |
| OpenAI Whisper | ~₹0.50 | 50+ languages | Very Good | ~200ms |
| ElevenLabs Scribe | ~₹0.56 | Indic languages | Good (10-25% WER) | ~180ms |
| Google Chirp | ~₹1.34 | 100+ languages | Excellent | ~200ms |
| Azure Speech | ~₹1.01 | 100+ languages | Excellent | ~180ms |
| AssemblyAI | ~₹0.65 | English-focused | Excellent | ~200ms |
STT Selection Guide
For English-primary deployments:
- Budget: Deepgram Nova-2 (₹0.35/min) - best price-to-quality ratio
- Quality: Google Chirp or Azure Speech - highest accuracy
For Indian languages (Hindi, Tamil, Telugu, etc.):
- Budget: ElevenLabs Scribe (₹0.56/min) - good Indic support
- Quality: Google Chirp (₹1.34/min) - best multilingual accuracy
For Assamese and regional languages:
- ElevenLabs Scribe or Azure Speech - limited options, test thoroughly
LLM (Language Model) Pricing
The LLM is the "brain" that understands intent and generates responses. This is often the most variable cost component.
Traditional LLM Providers (STT → LLM → TTS)
| Provider | Model | Cost/min* | Best For |
|---|---|---|---|
| Gemini 2.5 Flash-Lite | gemini-2.5-flash-lite | ~₹0.04 | Real-time voice, lowest latency |
| Gemini 2.0 Flash | gemini-2.0-flash | ~₹0.05 | Indic languages, balanced |
| GPT-4o-mini | gpt-4o-mini | ~₹0.08 | Good multilingual |
| Claude 3 Haiku | claude-3-haiku | ~₹0.10 | Fast, good reasoning |
| GPT-4o | gpt-4o | ~₹0.50 | Complex reasoning |
*Estimated for average 3-minute call with typical token usage
Native Audio LLM Providers (Direct Audio-to-Audio)
Native audio models bypass STT and TTS entirely, processing audio directly:
| Provider | Model | Cost/min | Voices | Latency |
|---|---|---|---|---|
| OpenAI Realtime Mini | gpt-4o-mini-realtime | ~₹4 | 8 voices | ~500ms |
| Gemini Live 2.5 HD | gemini-live-2.5-flash | ~₹8 | 30 HD voices | 377ms |
| OpenAI Realtime | gpt-4o-realtime | ~₹12 | 8 voices | ~500ms |
Important: Native audio pricing includes the equivalent of STT + LLM + TTS in a single cost. Compare against total traditional pipeline cost, not just LLM cost.
LLM Cost Example
For a traditional pipeline handling 10,000 minutes/month:
| Component | Provider | Cost/min | Monthly Cost |
|---|---|---|---|
| STT | Deepgram | ₹0.35 | ₹3,500 |
| LLM | Gemini 2.5 Flash-Lite | ₹0.04 | ₹400 |
| TTS | Sarvam Bulbul | ₹0.75 | ₹7,500 |
| Total | ₹1.14 | ₹11,400 |
Compare with native audio:
| Provider | Cost/min | Monthly Cost |
|---|---|---|
| Gemini Live 2.5 HD | ₹8 | ₹80,000 |
| OpenAI Realtime Mini | ₹4 | ₹40,000 |
Insight: Traditional pipelines are cheaper for high-volume deployments, but native audio offers better quality and lower latency.
TTS (Text-to-Speech) Pricing
TTS converts the AI's response into natural speech. This is where costs vary the most dramatically.
TTS Provider Comparison
| Provider | Cost/min | Languages | Quality | Latency |
|---|---|---|---|---|
| HeyPixa Luna | Free* | Hindi only | Good | ~300ms |
| Sarvam Bulbul | ~₹0.75 | 10 Indic | Very Good | ~200ms |
| Azure Neural | ~₹1.01 | 100+ | Excellent | ~150ms |
| OpenAI TTS | ~₹1.26 | Multilingual | Excellent | ~200ms |
| Google WaveNet | ~₹1.34 | 100+ | Excellent | ~180ms |
| Deepgram Aura | ~₹1.50 | English | Very Good | ~100ms |
| Cartesia Sonic | ~₹2.00 | Multilingual | Excellent | ~80ms |
| ElevenLabs | ~₹12.60 | Multilingual | Premium | ~200ms |
*HeyPixa Luna is currently free/unauthenticated (may change)
TTS Selection Guide
For Hindi deployments:
- Budget: HeyPixa Luna (free) - good quality, Hindi only
- Balanced: Sarvam Bulbul (₹0.75/min) - 10 Indic languages
- Premium: ElevenLabs (₹12.60/min) - highest quality
For English deployments:
- Budget: Azure Neural (₹1.01/min)
- Balanced: OpenAI TTS (₹1.26/min)
- Premium: ElevenLabs (₹12.60/min)
For lowest latency:
- Cartesia Sonic (~80ms) or Deepgram Aura (~100ms)
Telephony Pricing
Telephony costs include phone numbers, incoming/outgoing call charges, and connection fees.
Indian Telephony Providers
| Provider | DID Cost | Incoming | Outgoing | Best For |
|---|---|---|---|---|
| Exotel | ₹500/mo | ₹0.50/min | ₹0.80/min | Enterprise |
| Plivo | ₹300/mo | ₹0.40/min | ₹0.70/min | Scalability |
| Twilio | ₹400/mo | ₹0.60/min | ₹0.90/min | Global reach |
| Alohaa | ₹200/mo | ₹0.35/min | ₹0.65/min | Budget |
International Telephony
| Country | Provider | Incoming | Outgoing |
|---|---|---|---|
| US/Canada | Twilio | $0.0085/min | $0.014/min |
| UK | Twilio | $0.01/min | $0.015/min |
| UAE | Plivo | $0.02/min | $0.10/min |
Total Cost Examples
Example 1: Budget Hindi Voice Agent
| Component | Provider | Cost/min |
|---|---|---|
| STT | ElevenLabs Scribe | ₹0.56 |
| LLM | Gemini 2.5 Flash-Lite | ₹0.04 |
| TTS | HeyPixa Luna | ₹0.00 |
| Telephony | Alohaa | ₹0.35 |
| Total | ₹0.95/min |
Monthly cost for 10,000 minutes: ₹9,500
Example 2: Premium English Voice Agent
| Component | Provider | Cost/min |
|---|---|---|
| STT | Google Chirp | ₹1.34 |
| LLM | GPT-4o | ₹0.50 |
| TTS | ElevenLabs | ₹12.60 |
| Telephony | Twilio | ₹0.60 |
| Total | ₹15.04/min |
Monthly cost for 10,000 minutes: ₹1,50,400
Example 3: Native Audio (Gemini Live 2.5 HD)
| Component | Provider | Cost/min |
|---|---|---|
| Native Audio | Gemini Live 2.5 HD | ₹8.00 |
| Telephony | Exotel | ₹0.50 |
| Total | ₹8.50/min |
Monthly cost for 10,000 minutes: ₹85,000
Example 4: Balanced Multilingual Agent
| Component | Provider | Cost/min |
|---|---|---|
| STT | Deepgram Nova-2 | ₹0.35 |
| LLM | Gemini 2.0 Flash | ₹0.05 |
| TTS | Azure Neural | ₹1.01 |
| Telephony | Plivo | ₹0.40 |
| Total | ₹1.81/min |
Monthly cost for 10,000 minutes: ₹18,100
Cost Optimization Strategies
1. Choose the Right Architecture
| Volume | Best Architecture | Why |
|---|---|---|
| < 5,000 min/mo | Native Audio | Simpler, better quality |
| 5,000 - 50,000 min/mo | Evaluate both | Test ROI with actual calls |
| > 50,000 min/mo | Traditional Pipeline | Significant cost savings |
2. Match Providers to Use Case
Don't overpay for capabilities you don't need:
- English-only? Use Deepgram STT (saves ~₹1/min vs Google)
- Hindi-only? Use HeyPixa TTS (saves ~₹1/min vs Sarvam)
- Simple queries? Use Gemini Flash-Lite (saves ~₹0.50/min vs GPT-4o)
3. Optimize Call Duration
The single biggest cost factor is call length. Reduce average call duration by:
- Clear, concise AI responses
- Efficient conversation flows
- Quick intent detection
- Proactive information delivery
Example: Reducing average call from 4 min to 3 min saves 25% on all usage-based costs.
4. Use VAD Profiles Wisely
Voice Activity Detection (VAD) affects both cost and quality:
low_latency(100ms) - Faster turns, but may cut off speakersbalanced(200ms) - Good defaultconservative(350ms) - Better for Indian languages, longer pauses
Incorrect VAD settings cause repeated clarifications, increasing call duration.
5. Implement Caching
Cache common responses:
- Greetings and pleasantries
- FAQ answers
- Policy information
- Business hours
This reduces LLM calls significantly for high-volume deployments.
ROI Calculation
Cost Comparison: AI vs Human Agents
| Metric | Human Agent | AI Voice Agent |
|---|---|---|
| Cost per minute | ₹8-15/min | ₹2-8/min |
| Hours available | 8-12 hrs/day | 24/7 |
| Training time | 2-4 weeks | Instant updates |
| Scalability | Linear (hire more) | Instant |
| Consistency | Variable | 100% consistent |
Break-Even Analysis
Assuming:
- Human agent cost: ₹12/min (fully loaded)
- AI agent cost: ₹3/min (traditional pipeline)
- Monthly call volume: 10,000 minutes
| Scenario | Human Cost | AI Cost | Savings |
|---|---|---|---|
| 10,000 min/mo | ₹1,20,000 | ₹30,000 | ₹90,000 (75%) |
| 50,000 min/mo | ₹6,00,000 | ₹1,50,000 | ₹4,50,000 (75%) |
| 100,000 min/mo | ₹12,00,000 | ₹3,00,000 | ₹9,00,000 (75%) |
Hybrid Model
Most successful deployments use AI for:
- Tier 1 queries (60-70% of calls) - Fully automated
- Complex queries - AI assists human agent
- After-hours - 100% AI coverage
This typically achieves 50-60% cost reduction while maintaining customer satisfaction.
Edesy Pricing
On Edesy, you get transparent, usage-based pricing:
What's Included
| Feature | Included |
|---|---|
| Platform fee | Usage-based (no per-seat) |
| Agent builder | Unlimited agents |
| Integrations | CRM, Calendar, Custom APIs |
| Analytics | Full dashboard |
| Support | Email + Documentation |
Pay-As-You-Go Components
| Component | You Choose |
|---|---|
| STT Provider | 6 options |
| LLM Provider | 8 options |
| TTS Provider | 9 options |
| Telephony | BYOC or Edesy-provided |
Volume Discounts
| Monthly Volume | Discount |
|---|---|
| 0 - 10,000 min | Standard rates |
| 10,001 - 50,000 min | 10% off |
| 50,001 - 100,000 min | 15% off |
| 100,000+ min | Custom pricing |
Frequently Asked Questions
What's the cheapest way to run a voice AI agent?
The cheapest traditional pipeline:
- STT: Deepgram (₹0.35/min)
- LLM: Gemini 2.5 Flash-Lite (₹0.04/min)
- TTS: HeyPixa Luna (₹0.00/min, Hindi only)
- Total: ~₹0.40/min (plus telephony)
Is native audio worth the extra cost?
For sub-500ms latency requirements or when emotional AI matters, yes. Native audio (Gemini Live 2.5 HD at ₹8/min) provides:
- 50-70% faster response times
- Emotional detection and adaptation
- More natural conversations
- No "stitching" artifacts between STT/TTS
How do I estimate my monthly costs?
Formula:
Monthly Cost = (Avg Call Duration × Daily Calls × 30) × Cost Per Minute
Example:
- Average call: 3 minutes
- Daily calls: 100
- Cost per minute: ₹2.50
Monthly cost = 3 × 100 × 30 × ₹2.50 = ₹22,500
Can I switch providers mid-deployment?
Yes. On Edesy, you can change STT, TTS, or LLM providers from the dashboard without code changes. This allows you to:
- A/B test providers
- Optimize for cost or quality
- Adjust based on actual usage patterns
What hidden costs should I watch for?
- Number porting fees - One-time cost to transfer existing numbers
- Minimum commitments - Some providers require minimums
- Overage charges - Check what happens when you exceed limits
- API call limits - Some providers charge for metadata/analytics calls
Need help estimating costs for your specific use case? Contact the Edesy team for a personalized quote.