Which is cheaper, Claude Sonnet 5.5 and Gemini 3.5 Flash-Lite?

Gemini 3.5 Flash-Lite has the lowest input price. Per 1M input tokens: Claude Sonnet 5.5 from $2.00 and Gemini 3.5 Flash-Lite from $0.30.

Which has the larger context window, Claude Sonnet 5.5 and Gemini 3.5 Flash-Lite?

Gemini 3.5 Flash-Lite has the largest context window: Claude Sonnet 5.5 1,000,000 tokens and Gemini 3.5 Flash-Lite 1,048,576 tokens.

Which is smarter, Claude Sonnet 5.5 and Gemini 3.5 Flash-Lite?

Claude Sonnet 5.5 scores highest on the Artificial Analysis Intelligence Index: Claude Sonnet 5.5 54.2 and Gemini 3.5 Flash-Lite 11.7.

Can I switch between Claude Sonnet 5.5 and Gemini 3.5 Flash-Lite 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-sonnet-5.5, google/gemini-3.5-flash-lite).

Claude Sonnet 5.5 vs Gemini 3.5 Flash-Lite

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

Estimate monthly cost for these models

Claude Sonnet 5.5 Anthropicanthropic/claude-sonnet-5.5

Gemini 3.5 Flash-Lite Googlegoogle/gemini-3.5-flash-lite

Creator

Anthropic

Google

Released

Sep 28, 2026

Jul 21, 2026

Context window

1.05M

Max output

128K

66K

Input / 1MLowest provider price

$2.00

$0.30

Output / 1MLowest provider price

$10.00

$2.50

Providers

IntelligenceArtificial Analysis index

54.2

11.7

LatencyMedian time to first token

—

1.4s

ThroughputMedian tokens per second

—

<1 t/s

Accepts

Text, Image

Text, Image, Audio, Video, Files

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Sonnet 5.5 vs Gemini 3.5 Flash-Lite: summary

Claude Sonnet 5.5 and Gemini 3.5 Flash-Lite are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Sonnet 5.5, from Anthropic, has a 1,000,000-token context window, costs from $2.00/1M input and $10.00/1M output tokens across 3 providers and scores 54.2 on the Artificial Analysis Intelligence Index.

Gemini 3.5 Flash-Lite, from Google, has a 1,048,576-token context window, costs from $0.30/1M input and $2.50/1M output tokens across 2 providers and scores 11.7 on the Artificial Analysis Intelligence Index.

Gemini 3.5 Flash-Lite is the cheapest on input, 6.7× cheaper than the next model, Gemini 3.5 Flash-Lite has the largest context window and Claude Sonnet 5.5 scores highest for intelligence.

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-sonnet-5.5", messages=[...]) # or client.chat.completions.create(model="google/gemini-3.5-flash-lite", messages=[...])

Full API docs

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Benchmark scores sourced from ArtificialAnalysis