Gemini 3.1 Pro vs Claude Sonnet 4.6: the developer API cost face-off
Gemini 3.1 Pro is more economical across the board for both base input and output costs. Claude Sonnet 4.6 is preferred if you need Anthropic's specific coding and instruction-following strengths.
Coding workhorses and reasoning model showdown.
For complex coding and agentic reasoning, Gemini 3.1 Pro and Claude Sonnet 4.6 are the top contenders. Their cost structures depend heavily on prompt caching efficiency.
By TechCompare · Updated
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.
Side-by-side specs
| Spec | Gemini 3.1 Pro (<=200k) | Claude Sonnet 4.6 |
|---|---|---|
| Input Cost (per M) | $2.00 (better on this spec) | $3.00 |
| Output Cost (per M) | $12.00 (better on this spec) | $15.00 |
| Cached Input (per M) | $0.20 (better on this spec) | $0.30 |
| Batch Discount | 50% | 50% |
How they differ
Gemini 3.1 Pro costs $2.00 per million input tokens and $12.00 per million output tokens, with a 75% cache discount. Claude Sonnet 4.6 is priced at $3.00 per million input tokens and $15.00 per million output tokens, also with a 90% cache discount.
Verdict
Gemini charges $2.00/M input and $12.00/M output against Sonnet's $3.00 and $15.00, so it wins every base row by 33% on input and 20% on output. The cached row flips: Sonnet's deeper 90% discount lands at $0.30/M against Gemini's $0.50/M (75% off $2.00), so heavy prompt reuse favors Sonnet on input. Sonnet's other edge is ergonomic: tighter tool use and instruction following, plus a 500K context that is usually enough for agentic loops. Pick it for the cache and the ergonomics, not the base bill.
Which should you pick?
Choose Gemini 3.1 Pro (<=200k)
Massive context size processing (up to 2M tokens) and general cost savings.
Choose Claude Sonnet 4.6
State-of-the-art multi-file code editing, tool use, and agentic loops.