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HEAD TO HEAD · UPDATED NOV 6, 2026
Gemini 3.8 Flash vs Claude Sonnet 5.5
Google DeepMind against Anthropic, on sourced numbers only. Green marks the higher (or cheaper) value on each row; the text below only calls a lead when the gap is bigger than measurement noise.
| Gemini 3.8 Flash | Claude Sonnet 5.5 | |
|---|---|---|
| Arena Elo | 1496 source ↗ | 1477 source ↗ |
| GPQA Diamond | 95.4% source ↗ | 95.6% source ↗ |
| $ per 1M in / out | $0.75 / $3.75 source ↗ | $2 / $10 source ↗ |
| Blended $ per 1M (3:1) | $1.50 source ↗ | $4.00 source ↗ |
| Context window | 1M source ↗ | 1M source ↗ |
| Output speed | 117 tok/s source ↗ | 155 tok/s source ↗ |
| Released | Sep 2, 2026 source ↗ | Sep 28, 2026 source ↗ |
| Open weights | No source ↗ | No source ↗ |
| Reasoning effort tiers | low · medium · high (default: medium) | low · medium · high · xhigh · max (default: high) |
| API effort control | thinking_config={"thinking_level": "low" | "medium" | "high"} source ↗ | output_config={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ |
| Additional benchmarks | DeepSWE v1.1: 73.7% source ↗ | SWE-bench Pro: 81.3% source ↗ AA Intelligence Index v5.0.1: 55 source ↗ |
| Best for (workload) | 95.4% on GPQA Diamond (Epoch AI) and 117 tok/s output (Artificial Analysis) at a Flash-tier price. source ↗ | Fast (155 tok/s, Artificial Analysis) and strong on science: 95.6% GPQA Diamond at max effort (Epoch AI), above Opus 5.5's 90.6%. source ↗ |
Arena Elo from the arena.ai text leaderboard as of Oct 27, 2026 source ↗. Speed measured by Artificial Analysis and varies by provider.
Which one should I use?
For high-volume work where cost matters most, Gemini 3.8 Flash is about 2.7 times cheaper per token. For latency-sensitive use such as live chat, Claude Sonnet 5.5 is noticeably faster (155 vs 117 tokens per second). On release timing, Google DeepMind is at day 24 of a typical ~32-day gap (MID-CYCLE), and Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP).
Key differences from the sourced numbers
- Gemini 3.8 Flash is the cheaper option: $1.50 vs $4.00 per 1M tokens at a 3:1 input-to-output mix (about 2.7 times less).
- On the Arena text leaderboard they are close (1496 vs 1477): a gap under 20 points is within the leaderboard's margin of error.
- On GPQA Diamond they are close (95.4% vs 95.6%).
- Claude Sonnet 5.5 streams output faster: 155 vs 117 tokens per second (Artificial Analysis).
- Gemini 3.8 Flash pricing note: Until Dec 31, 2026; $1.50 / $7.50 from Jan 1, 2027. No higher rate for long prompts.
- Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window.
Frequently asked questions
Is Gemini 3.8 Flash or Claude Sonnet 5.5 better?
Gemini 3.8 Flash is the cheaper option: $1.50 vs $4.00 per 1M tokens at a 3:1 input-to-output mix (about 2.7 times less). On the Arena text leaderboard they are close (1496 vs 1477): a gap under 20 points is within the leaderboard's margin of error. On GPQA Diamond they are close (95.4% vs 95.6%). Claude Sonnet 5.5 streams output faster: 155 vs 117 tokens per second (Artificial Analysis). Gemini 3.8 Flash pricing note: Until Dec 31, 2026; $1.50 / $7.50 from Jan 1, 2027. No higher rate for long prompts. Claude Sonnet 5.5 pricing note: Same rate across the full 1M context window.
Which one should I use: Gemini 3.8 Flash or Claude Sonnet 5.5?
For high-volume work where cost matters most, Gemini 3.8 Flash is about 2.7 times cheaper per token. For latency-sensitive use such as live chat, Claude Sonnet 5.5 is noticeably faster (155 vs 117 tokens per second). On release timing, Google DeepMind is at day 24 of a typical ~32-day gap (MID-CYCLE), and Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP).
How much does Gemini 3.8 Flash cost compared with Claude Sonnet 5.5?
Gemini 3.8 Flash lists at $0.75 / $3.75 per 1M input/output tokens ($1.50/1M blended at 3:1). Claude Sonnet 5.5 lists at $2 / $10 per 1M input/output tokens ($4.00/1M blended at 3:1).
Facts checked Nov 5, 2026 against official sources. Every number links to its source. Spotted an error? Email [email protected].