External variables (as of February 2026)
Input: $1/MTok
Output: $5/MTok
Tokens per second: ~110 TPS
Assumptions
Typical ratio of input to output tokens: 5:1
No caching, using extended thinking
5% of time is downtime: constructing prompts, waiting for tool calls, time to first token, etc.
Steps
110 TPS x 3600 sec/hr = ~0.4 MTok/hr output = $2/hr
5:1 ratio means ~2 MTok/hr input = $2/hr
Total of $4/hr with input and output tokens combined
~$3.80/hr assuming only 5% downtime
Result
Running Haiku 4.5 continuously costs ~$3.8/hr
Interpretations
If you are running an agent 12 hr/day, 30 days/month, it comes out to ~$1.4k per month
If you are limited to $100/month, you can pay for ~50 min/day
Adjustments for Continuous Opus 4.6 usage
Opus costs 5x more per token
Comes out to ~3.4x Haiku cost, so ~$12.90/hr, or $4.6k per month