text model comparison
Claude Sonnet 5.5 vs Gemini 3.8 Flash
Claude Sonnet 5.5 and Gemini 3.8 Flash are both current text models, from Anthropic and Google. Gemini 3.8 Flash is 63% cheaper per 1M input tokens than Claude Sonnet 5.5, $0.75 vs $2. On Arena Text, Claude Sonnet 5.5 scores 1476 Elo and Gemini 3.8 Flash 1497 Elo (Arena, measured October 8, 2026). Both accept about 1.05M tokens of context (1,048,576 and 1,000,000).
Data verified October 12, 2026 · Dataset 2026-10-12
Side by side
Standard-tier prices in effect today. The better value in each row is highlighted.
| Fact | Claude Sonnet 5.5 | Gemini 3.8 Flash |
|---|---|---|
| Price per 1M input tokens | $2 | $0.75 (better) |
| Price per 1M output tokens | $10 | $3.75 (better) |
| Cost of 10M input and 2M output tokens | $40 | $15 (better) |
| Arena Text | 1476 Elo (#17 of 39) | 1497 Elo (#4 of 39) (better) |
| GPQA Diamond | 95.6% (#2 of 37) (better) | 95.4% (#3 of 37) |
| FrontierMath Tiers 1-3 (v2) | 88.8% (#7 of 37) (better) | 68.4% (#21 of 37) |
| SimpleQA Verified | 46.5% (#21 of 34) | 69.7% (#7 of 34) (better) |
| Provider | Anthropic | |
| Release date | September 28, 2026 | September 2, 2026 |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 1,048,576 tokens |
| Max output | 128,000 tokens | 65,536 tokens |
| Input | text, image | text, image, audio, video |
| Output | text | text |
When to choose each
Claude Sonnet 5.5
Best for
- Production workloads that need frontier-adjacent quality at a mid-tier rate
- Latency-sensitive agent steps inside a larger pipeline
Watch out for
- Same list price as Claude Sonnet 5, so the gain is capability and cache economics rather than a cheaper rate card
- Anthropic positions Opus 5.5 rather than this as the default, so reach for Sonnet 5.5 when latency matters more than peak capability
Gemini 3.8 Flash
Best for
- High-volume agentic and coding workloads where per-token cost dominates the decision
- Multimodal pipelines that need audio, video and PDF input in one model
Watch out for
- The listed price is promotional and ends 31 December 2026; on 1 January 2027 input and output both double, to $1.50 and $7.50, and cached input goes from $0.075 to $0.15
- Output pricing is billed inclusive of thinking tokens, so reasoning-heavy prompts cost more than the output length suggests
- Google’s published comparisons are against its own previous Flash release and were not independently reproduced here
Claude Sonnet 5.5 vs Gemini 3.8 Flash FAQ
Which is cheaper, Claude Sonnet 5.5 or Gemini 3.8 Flash?
Gemini 3.8 Flash is 63% cheaper per 1M input tokens than Claude Sonnet 5.5, $0.75 vs $2. For 10M input and 2M output tokens, Claude Sonnet 5.5 costs $40 and Gemini 3.8 Flash $15 at standard rates.
Which scores higher on independent benchmarks, Claude Sonnet 5.5 or Gemini 3.8 Flash?
Gemini 3.8 Flash leads on Arena Text, 1497 Elo to 1476 Elo; Claude Sonnet 5.5 leads on GPQA Diamond, 95.6% to 95.4%; Claude Sonnet 5.5 leads on FrontierMath Tiers 1-3 (v2), 88.8% to 68.4%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, Claude Sonnet 5.5 or Gemini 3.8 Flash?
Both accept about 1.05M tokens of context (1,048,576 and 1,000,000).
Related comparisons
- Claude Opus 4.8 vs Gemini 3.8 Flash
- Claude Opus 5.5 vs Gemini 3.8 Flash
- Claude Opus 5 vs Gemini 3.8 Flash
- Claude Sonnet 5.5 vs GPT-4.1
- Claude Sonnet 5.5 vs GPT-5.4
- Claude Sonnet 5.5 vs GPT-5.6 Terra
- Claude Sonnet 5.5 vs GPT-6.1 Sol
- Claude Sonnet 5.5 vs GPT-6 Sol
- Claude Sonnet 5.5 vs Grok 4.5
- Claude Sonnet 5.5 vs Grok 4.6
Production evaluation
Choosing between Claude Sonnet 5.5 and Gemini 3.8 Flash?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty