Which is cheaper, Claude Opus 5 and Gemini 3.8 Flash?

Gemini 3.8 Flash has the lowest input price. Per 1M input tokens: Claude Opus 5 from $5.00 and Gemini 3.8 Flash from $0.75.

Which has the larger context window, Claude Opus 5 and Gemini 3.8 Flash?

Gemini 3.8 Flash has the largest context window: Claude Opus 5 1,000,000 tokens and Gemini 3.8 Flash 1,048,576 tokens.

Which is better for coding, Claude Opus 5 and Gemini 3.8 Flash?

Claude Opus 5 scores highest on the Artificial Analysis Coding Index: Claude Opus 5 76.5 and Gemini 3.8 Flash 76.3.

Which is smarter, Claude Opus 5 and Gemini 3.8 Flash?

Claude Opus 5 scores highest on the Artificial Analysis Intelligence Index: Claude Opus 5 48.1 and Gemini 3.8 Flash 40.9.

Can I switch between Claude Opus 5 and Gemini 3.8 Flash without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (anthropic/claude-opus-5, google/gemini-3.8-flash).

Claude Opus 5 vs Gemini 3.8 Flash

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Claude Opus 5 Anthropicanthropic/claude-opus-5

Gemini 3.8 Flash Googlegoogle/gemini-3.8-flash

Creator

Anthropic

Google

Released

Jul 24, 2026

Sep 2, 2026

Context window

1.05M

Max output

128K

66K

Input / 1MLowest provider price

$5.00

$0.75

Output / 1MLowest provider price

$25.00

$3.75

Providers

IntelligenceArtificial Analysis index

48.1

40.9

CodingArtificial Analysis index

76.5

76.3

LatencyMedian time to first token

30s

—

ThroughputMedian tokens per second

<1 t/s

—

Accepts

Text, Image, Files

Text, Image, Audio, Video, Files

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Opus 5 vs Gemini 3.8 Flash: summary

Claude Opus 5 and Gemini 3.8 Flash are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Opus 5, from Anthropic, has a 1,000,000-token context window, costs from $5.00/1M input and $25.00/1M output tokens across 3 providers and scores 48.1 on the Artificial Analysis Intelligence Index.

Gemini 3.8 Flash, from Google, has a 1,048,576-token context window, costs from $0.75/1M input and $3.75/1M output tokens across 2 providers and scores 40.9 on the Artificial Analysis Intelligence Index.

Gemini 3.8 Flash is the cheapest on input, 6.7× cheaper than the next model, Gemini 3.8 Flash has the largest context window, Claude Opus 5 scores highest for intelligence and Claude Opus 5 leads on coding.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="anthropic/claude-opus-5", messages=[...]) # or client.chat.completions.create(model="google/gemini-3.8-flash", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis