Cost Per Conversation Calculator
Estimate LLM cost and margin per conversation.
With the default inputs, $0.00156 per conversation — Margin $0.4984 at $0.5000 revenue. Enter your own numbers below to recompute instantly; the full step-by-step math is shown under the worked example.
Results update automatically as you type.
- Messages
- 8
- Cost per conversation
- $0.00156
- Margin
- $0.4984
Estimate what a single AI conversation costs and, if you charge for it, your margin. Set messages per conversation and average tokens to see the per-conversation cost.
How this is calculated
Cost per conversation = messages per conversation × (input tokens per message × input price + output tokens per message × output price), using your model's live per-token rates. If you enter revenue per conversation, we subtract the model cost to show gross margin per conversation.
This is a simpler, flat model than the chatbot calculator: it assumes a steady token size per message rather than growing history, which is a good approximation when you trim or window history.
Is this a good result? What to do next
For a monetised conversation, aim for model cost well under ~20–30% of revenue per conversation so there's room for infrastructure, support and profit. For an internal tool, compare it to the human cost of the same interaction — a support conversation handled by a person can cost several dollars, so cents per AI conversation is a large saving.
Typical planning ranges
- Mini/budget model, short conversation
- ~$0.002–$0.02
- Mid-tier model, longer conversation
- ~$0.03–$0.20
- Healthy model-cost share of revenue
- < 20–30%
Ranges are typical planning figures to sanity-check your result, not authoritative benchmarks. Your numbers will vary with use case, volume, and vendor.
How to improve this number
- Use a smaller model or trim messages per conversation.
- Shorten responses and system prompt; cache repeated context.
- Raise or add revenue per conversation if margin is thin.
Common mistakes
- Ignoring the system prompt, which is re-sent on most messages.
- Assuming a fixed message count when real conversations vary widely.
- Costing only the model and forgetting support and infra overhead.
When to use a different approach
If history genuinely grows through the session, the chatbot cost calculator models that growth more accurately. To price per seat or per user, use the per-seat or cost-per-user calculators.
Worked example (defaults)
With the default inputs above, here is the result:
- Messages
- 8
- Cost per conversation
- $0.00156
- Margin
- $0.4984
Sources & references
Frequently asked questions
How do I price an AI feature?+
Estimate cost per conversation, add infrastructure and margin, and make sure your price or plan covers heavy users. This calculator gives the model cost baseline.
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