Head-to-head
Gemini 3.5 Flash vs Claude Opus 4.5: which AI model wins in 2026?
Gemini 3.5 Flash ($9.00/1M out) and Claude Opus 4.5 ($25/1M out) are two of the most-used AI models in 2026. Compare them line by line below, then cast your verdict.
Quick verdict
On Reasoning, Gemini 3.5 Flash and Claude Opus 4.5 are tied at 3.5/5. On budget, Gemini 3.5 Flash wins: it starts at $9.00/1M out versus $25/1M out for Claude Opus 4.5.
Line-by-line comparison
From
$9.00/1M outPaid tier flat rate $1.50/$9.00 per 1M; batch API 50% off ($0.75/$4.50), context caching $0.15/1M plus $1.00/1M per hour storage, free tier available
$25/1M outOfficial Anthropic API list price for claude-opus-4-5 (single tier, no long-context premium; 200K context, 64K max output); same $5/$25 rate as its Opus 4.6-4.8 successors; 50% batch discount and prompt caching apply. Verified against platform.claude.com models overview 2026-07.
Provider
Google
Anthropic
Context window
1M tokens (1,048,576 in / 65,536 out)
200K tokens
Input price
$1.50/1M in
$5/1M in
Output price
$9.00/1M out
$25/1M out
Modalities
text, vision, audio, video, PDF in; text out
text, vision
Open weights
No
No
Crowd score
50%(0)
50%(0)
Arena ratings (1-5)
Reasoning
3.5
3.5
Coding
4.0
3.5
Writing
3.0
3.5
Speed
5.0
2.5
Value
4.5
2.5
Strengths and weaknesses
Gemini 3.5 Flash
- Beats Gemini 3.1 Pro on agentic benchmarks: 76.2% Terminal-Bench 2.1, 1656 Elo GDPval-AA (vs 1314 for 3.1 Pro), 83.6% MCP Atlas
- Artificial Analysis Intelligence Index 50 at high thinking effort, ranking #10 of 170 tracked models
- Very fast generation (~185 output tokens/sec per Artificial Analysis); Google claims 4x faster output than other frontier models
- 1M-token context window (1,048,576) with multimodal input: text, image, audio, video, PDF
- 25% cheaper than Gemini 3.1 Pro ($1.50/$9 vs $2/$12) while outperforming it on production agent workloads
- Adjustable thinking effort (minimal/low/medium/high) plus 50% batch discount and $0.15/1M context caching
- 3x price increase over Gemini 3 Flash ($0.50/$3.00) and 5-6x over 2.5 Flash; HN devs saw it as Google probing price tolerance
- Over-eager and verbose: devs report it ignores completion criteria and embellishes beyond instructions (compared to Claude's 'Sonnet 3.7 moment')
- Reliability complaints on Flash serving: developers report frequent 503 errors during peak periods
- Weaker on long-horizon agentic tasks with arbitrary tool availability, a recurring theme devs report with Google models
- High time-to-first-token (~23s at high thinking effort per Artificial Analysis), poor fit for latency-sensitive chat
Claude Opus 4.5
- First model past 80% on SWE-bench Verified (80.9% at launch), beating Gemini 3 Pro and GPT-5.1 on real-world coding
- 66% price cut vs Opus 4.1 ($5/$25 vs $15/$75 per 1M tokens) made Opus-tier viable for production workloads
- 48-76% fewer output tokens than Sonnet 4.5 at matched or better quality, compounding the price cut
- Effort parameter (introduced with this model) lets devs trade reasoning depth for cost and latency per call
- Strong hands-on reports: one-shot complex refactors, caught race conditions other models missed, converged in ~4 agentic iterations vs ~10 for rivals
- +29% on Vending-Bench vs Sonnet 4.5, with fewer dead-ends on long-horizon autonomous tasks
- 200K context window only (64K max output), far behind the 1M of Gemini 3 Pro and later Claude models; users reported selective attention above ~70% context fill
- Gated to $100-200/month Max tiers in Claude apps at launch; Pro subscribers were locked out and heavy users still hit limits (HN called it 'penny-wise and pound-foolish')
- Moderate latency; extended thinking adds cost and delay on simple tasks
- Superseded since early 2026: Opus 4.6/4.7/4.8 cost the same $5/$25 with 1M context and higher benchmarks, leaving 4.5 no price advantage
- Legacy API surface: manual budget_tokens extended thinking rather than the adaptive thinking of newer Claude models
Cast your verdict
One recommendation per tool per gladiator. It reshapes the crowd score everyone sees.
Gemini 3.5 Flash$9.00/1M out
50%crowd score · 0
Claude Opus 4.5$25/1M out
50%crowd score · 0
The arena’s verdict on Gemini 3.5 Flash
Pick Gemini 3.5 Flash if you run agentic coding or high-volume multimodal pipelines and want near-Pro quality at 4x the speed: it actually beats Gemini 3.1 Pro on Terminal-Bench and GDPval while costing 25% less. Avoid it if you used the Flash line as a budget tier, since it costs 3x its predecessor Gemini 3 Flash, which remains the cheap option at $0.50/$3.00. Also skip it for latency-sensitive chat at high thinking effort (~23s to first token) or strict, no-embellishment output where its verbosity works against you.
The arena’s verdict on Claude Opus 4.5
Pick Claude Opus 4.5 only if you have a workload already tuned and pinned to this snapshot (claude-opus-4-5-20251101) and need stability. It was a landmark release, the first past 80% on SWE-bench Verified and a 66% price cut over Opus 4.1, but Anthropic now sells Opus 4.6 through 4.8 at the identical $5/$25 rate with a 1M context window and better scores. Anyone starting a new project should choose Opus 4.8 instead, and cost-sensitive users get near-Opus coding from Sonnet 5 at $3/$15 (intro $2/$10 through Aug 2026). Avoid it entirely if your prompts approach the 200K context ceiling.
Keep comparing
Full Gemini 3.5 Flash reviewFull Claude Opus 4.5 reviewGemini 3.5 Flash alternativesClaude Opus 4.5 alternativesGemini 3.5 Flash vs Claude Haiku 4.5Claude Opus 4.5 vs Claude Haiku 4.5Gemini 3.5 Flash vs Claude Opus 4.7Claude Opus 4.5 vs Claude Opus 4.7Gemini 3.5 Flash vs Claude Opus 4.8Claude Opus 4.5 vs Claude Opus 4.8Full AI model leaderboardTool finder
Frequently asked questions
Is Gemini 3.5 Flash better than Claude Opus 4.5?
The right pick depends on your use case. The line-by-line comparison on this page breaks down pricing, key specs and arena ratings.
Which is cheaper, Gemini 3.5 Flash or Claude Opus 4.5?
Gemini 3.5 Flash is cheaper: it starts at $9.00/1M out, while Claude Opus 4.5 starts at $25/1M out.
How much do Gemini 3.5 Flash and Claude Opus 4.5 cost per 1M tokens?
Gemini 3.5 Flash: $1.50/1M in per 1M input tokens, $9.00/1M out per 1M output tokens. Claude Opus 4.5: $5/1M in per 1M input tokens, $25/1M out per 1M output tokens.