A worked estimate you can check line by line. Change the numbers to your own in the cost calculator.
What we assume
One task is an agent loop of 25 model calls. On an average call the agent re-sends about 30,000 tokens (instructions, tool list, files it has read and earlier steps), adds about 3,000 new tokens of tool results, and writes 1,500 tokens of reasoning, edits or tool calls.
Cost per task
| Model | No caching | With caching | Per 1,000 tasks, with caching |
|---|---|---|---|
| Claude Fable 5.2 | $8.10 | $2.40 | $2,400 |
| Claude Opus 5.5 | $4.05 | $1.27 | $1,275 |
| Claude Sonnet 5.5 | $2.02 | $0.637 | $638 |
| Claude Haiku 5.5 | $0.101 | $0.036 | $35.63 |
Cost per month
| Model | One developer (100 tasks/month) | Team of 20 developers |
|---|---|---|
| Fable 5.2 | $240 | $4,800 |
| Opus 5.5 | $127 | $2,550 |
| Sonnet 5.5 | $63.75 | $1,275 |
| Haiku 5.5 | $3.56 | $71.25 |
Where the money goes
- Agent loops are where caching matters most: almost everything on each call was already sent on the previous call.
- Cap the number of steps and the dollars per task. A loop that keeps calling tools is the classic surprise bill.
- Large tool results (whole files, long logs) fill the context fast. Return only what the model needs.
To check what a plan price leaves you after these costs, use the AI SaaS margin calculator. To see how much caching saves on your own prompt sizes, use the prompt caching savings calculator.
Questions
How much does one task cost with the Claude API?
With prompt caching, from about $0.036 on Claude Haiku 5.5 to about $2.40 on Claude Fable 5.2, for a task of 25 calls × (30,000 reused + 3,000 new input tokens, 1,500 output tokens). Without caching it is $0.101 to $8.10.
How much does it cost per month?
One developer (100 tasks/month): about $3.56 on Haiku 5.5 up to $240 on Fable 5.2. Team of 20 developers: about $71.25 on Haiku 5.5 up to $4,800 on Fable 5.2, with caching.
How can I make it cheaper?
Agent loops are where caching matters most: almost everything on each call was already sent on the previous call.