Running Haiku 4.5 continuously in an agent harness would cost ~$4/hr

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

Opus inference is slower, ~75 TPS

Comes out to ~3.4x Haiku cost, so ~$12.90/hr, or $4.6k per month