Cost Analysis: AI Voice Agents vs Human Call Center (Real ROI Calculation)

If you’re comparing 5 human call center agents costing $15,000/month to running the same volume on AutoCallFlow, the AI option will usually be 70–95% cheaper depending on per-minute PSTN costs and plan choices. Below I show exact, step-by-step arithmetic for low / mid / high carrier-cost scenarios, per-call costs, monthly savings, and annualized ROI — so you can justify the purchase to a CFO right now.

Key assumptions (we’ll be explicit)

I build the math from a concrete, repeatable baseline so you (or your CFO) can adjust numbers and re-run.

Human side (given):

• 5 human agents cost = $15,000 / month (your input)

Operational assumptions (human productivity):

• Productive calls per hour per agent = 12
• Productive hours per day per agent = 8
• Working days per month = 22

Derived (human):

• Calls per agent per day = 12 × 8 = 96
• Calls per agent per month = 96 × 22 = 2,112
• Calls for 5 agents per month = 2,112 × 5 = 10,560 calls
• Average call length (minutes) = 3 minutes (conservative for qualification/booking)
• Total minutes per month = 10,560 calls × 3 minutes = 31,680 minutes

I computed these step-by-step so you can change any input and immediately see the new result.

The AI side — cost components we include

For AutoCallFlow (or any similar AI dialer) the real monthly cost =

Platform fee + Carrier minutes + TTS/STT/LLM processing + Number rental & infra + Storage/other

To be conservative, I include a small LLM/TTS/STT processing cost and a tiny storage line.

Typical line-item assumptions used below:

• Platform fee (AutoCallFlow Pro example) = $79 / month
• Number rental = $5 per number; assume a small pool (3 numbers) ⇒ 3 × $5 = $15 / month
• Storage & misc = $10 / month
• TTS/STT/LLM processing cost = $0.01 per minute (conservative combined estimate)

Carrier PSTN cost scenarios (per minute):

• Low: $0.02 / minute
• Mid: $0.05 / minute
• High: $0.10 / minute

You can substitute your exact platform fee / number rental / per-minute costs — I show formulas so it’s trivial.

Step-by-step arithmetic (digit-by-digit)

1) Human baseline (given)

Human cost per month = $15,000

2) Derived call volumes

Productive calls per hour per agent = 12
Hours/day = 8 → calls/day per agent = 12 × 8 = 96
Days/month = 22 → calls/month per agent = 96 × 22 = 2,112
For 5 agents: 2,112 × 5 = 10,560 calls / month
Average call length 3 min → total minutes = 10,560 × 3 = 31,680 minutes / month

3) AI cost per-minute (three scenarios)

We compute total AI cost = Platform fee + Number rental + Storage + (Minutes × (Carrier + LLM))

A — Low-cost PSTN (carrier $0.02/min)

Total AI monthly cost = $950.40 (usage) + $79 (platform) + $15 (numbers) + $10 (storage) = $1,054.40

Savings vs humans: $15,000 − $1,054.40 = $13,945.60 saved / month (93% savings)

Per-call cost: $0.10 (AI) vs $1.42 (Human)

B — Mid-cost PSTN (carrier $0.05/min)

Total AI monthly cost = $1,900.80 + $104 = $2,004.80

Savings: $15,000 − $2,004.80 = $12,995.20 saved / month (87% savings)

Per-call cost: $0.19 (AI)

C — High-cost PSTN (carrier $0.10/min)

Total AI monthly cost = $3,484.80 + $104 = $3,588.80

Savings: $15,000 − $3,588.80 = $11,411.20 saved / month (76% savings)

Per-call cost: $0.34 (AI)

Summary Table

Annualized view & payback

Annual savings range from $136,934 to $167,347 per year. A one-time setup fee is paid back in less than a month.

Cost-per-conversion perspective

If 10,560 calls yield 100 appointments:

• AI cost per appointment: $10.54
• Human cost per appointment: $150

AI dramatically lowers the cost per qualified lead.

Conclusion — the CFO-friendly summary

Replacing 5 human agents with AI agents on AutoCallFlow typically yields monthly savings of $11k–$14k. The cost per call is an order of magnitude lower (≈$0.10–$0.34 vs $1.42). The best approach is often hybrid: AI for qualification, humans for closing.