Claude API
What is the difference between input tokens and output tokens for billing?
QUICK ANSWER
Input tokens represent all prompt text, system instructions, and tool definitions sent to Claude, billed at a lower rate (e.g., $3/M tokens for Sonnet). Output tokens represent the generated completion text, billed at a higher rate (e.g., $15/M tokens for Sonnet).
Pricing Table (Per Million Tokens)
| Model Name | Input Price (per M) | Output Price (per M) | Prompt Cache Write | Prompt Cache Read |
|---|---|---|---|---|
| Claude 3.5 Sonnet | $3.00 | $15.00 | $3.75 | $0.30 |
| Claude 3.5 Haiku | $0.80 | $4.00 | $1.00 | $0.08 |
| Claude 3 Opus | $15.00 | $75.00 | N/A | N/A |
Verified against: Anthropic API Pricing July 2026