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Comparison · 3 models · Updated Oct 4, 2026

Claude Sonnet 3.5 v2 vs Claude Opus 4 vs Gemini 2.0 Flash

Too close to call on our weighted score (Gemini 2.0 Flash 65, Claude Opus 4 64, Claude Sonnet 3.5 v2 54). The right pick depends on what you value most.

  1. Anthropic

    Claude Sonnet 3.5 v2

    Released Oct 22, 2024

    54/100
    • ECI133.5
    • Price$3.00 / $15.00
    • Context200K
    Full specs Remove Claude Sonnet 3.5 v2

  2. Anthropic

    Claude Opus 4

    Released May 22, 2025

    64/100
    • ECI142.7
    • Price$15.00 / $75.00
    • Context200K
    Full specs Remove Claude Opus 4

  3. Google

    Gemini 2.0 Flash

    Released Dec 11, 2024

    65/100
    • ECI134.7
    • Price—
    • Context1.05M
    Full specs Remove Gemini 2.0 Flash
01 — Verdict

Too close to call

It is close. Our weighted score puts them within 1 points (Gemini 2.0 Flash 65/100, Claude Opus 4 64/100, Claude Sonnet 3.5 v2 54/100), so choose by what matters most for your work: Claude Opus 4 for raw capability, Claude Sonnet 3.5 v2 on price and Gemini 2.0 Flash for long inputs. The score weighs capability 67%, inputs & features 20%, context window 13%.

  • CapabilityClaude Opus 4Capabilities Index (ECI): Claude Opus 4 142.7 · Gemini 2.0 Flash 134.7 · Claude Sonnet 3.5 v2 133.5
  • Lowest priceClaude Sonnet 3.5 v2Claude Sonnet 3.5 v2 $6.00 · Claude Opus 4 $30.00 per 1M tokens (3:1 blend) · Gemini 2.0 Flash unpriced
  • Longest contextGemini 2.0 FlashGemini 2.0 Flash 1,048,576 · Claude Sonnet 3.5 v2 200,000 · Claude Opus 4 200,000 tokens
  • Widest inputsGemini 2.0 FlashClaude Sonnet 3.5 v2: Text, Images, PDFs · Claude Opus 4: Text, Images, PDFs · Gemini 2.0 Flash: Text, Images, PDFs, Audio, Video
  • Self-hostingNo open weightsAll three are available only through APIs
How the score is built
MeasureWeightClaude Sonnet 3.5 v2Claude Opus 4Gemini 2.0 Flash
CapabilityCapabilities Index (ECI)67%576959
Inputs & features20%607090
Context window13%323261
Overall100%54/10064/10065/100

Left out because at least one model lacks the data: price. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Claude Sonnet 3.5 v2 vs Claude Opus 4 vs Gemini 2.0 Flash specifications side by side
SpecificationClaude Sonnet 3.5 v2AnthropicClaude Opus 4AnthropicGemini 2.0 FlashGoogle
Capability
Capabilities Index (ECI)133.5142.7 (best)134.7
ECI rank#119 of 148#87 of 148 (best)#116 of 148
GPQA DiamondGraduate-level science questions55.3%76.3% (best)—
OTIS Mock AIME 2024–2025Competition mathematics8.5%64.4% (best)—
SWE-bench VerifiedFixing real GitHub issues—70.7%—
Price per million tokens
Input$3.00 (best)$15.00—
Output$15.00 (best)$75.00—
Cached input———
Blended (3:1)$6.00 (best)$30.00—
Long-context rateSame rateSame rate—
Price sourceMedian of 1 providersMedian of 5 providers—
Limits
Context window200,000 tokens200,000 tokens1,048,576 tokens (best)
Max output8,192 tokens32,000 tokens (best)8,192 tokens
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsYesYesYes
AudioNoNoYes
VideoNoNoYes
ReasoningNoYesNo
Tool callingYesYesYes
Structured outputNoNoYes
Availability
WeightsProprietaryProprietaryProprietary
API model ID———
API providers15 (best)—
ReleasedOct 22, 2024May 22, 2025Dec 11, 2024
Knowledge cutoffApr 30, 2024Mar 31, 2025Jun 2024
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Claude Sonnet 3.5 v2$60.00
  • Claude Opus 4$300.00
  • Gemini 2.0 Flash—
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 3.5 v2, Claude Opus 4 or Gemini 2.0 Flash?

It is close. Our weighted score puts them within 1 points (Gemini 2.0 Flash 65/100, Claude Opus 4 64/100, Claude Sonnet 3.5 v2 54/100), so choose by what matters most for your work: Claude Opus 4 for raw capability, Claude Sonnet 3.5 v2 on price and Gemini 2.0 Flash for long inputs. The score weighs capability 67%, inputs & features 20%, context window 13%.

Which is cheaper, Claude Sonnet 3.5 v2, Claude Opus 4 or Gemini 2.0 Flash?

Claude Sonnet 3.5 v2 is cheaper at $3.00 input / $15.00 output per million tokens (median across 1 API provider). Claude Opus 4 costs $15.00 input / $75.00 output per million tokens (median across 5 API providers). At a typical mix of three input tokens to one output token, that is $6.00 per million tokens for Claude Sonnet 3.5 v2 versus $30.00 for Claude Opus 4 (5× as much). Gemini 2.0 Flash has no published per-token price.

Which scores higher on benchmarks?

Claude Opus 4 scores higher on the Capabilities Index (ECI): Claude Opus 4 142.7 (#87 of 148), Gemini 2.0 Flash 134.7 (#116 of 148) and Claude Sonnet 3.5 v2 133.5 (#119 of 148). Their confidence ranges do not overlap (140.2–144.2 vs 124.3–136.7), so the gap is a real one.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Sonnet 3.5 v2 and Gemini 2.0 Flash yet, so there is no like-for-like coding score. On overall capability, Claude Opus 4 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

Gemini 2.0 Flash has the largest context window at 1,048,576 tokens, against 200,000 for Claude Sonnet 3.5 v2 and 200,000 for Claude Opus 4. Maximum output per response: Claude Sonnet 3.5 v2 up to 8,192, Claude Opus 4 up to 32,000, Gemini 2.0 Flash up to 8,192 tokens.

Which can read images, PDFs, audio or video?

Claude Sonnet 3.5 v2 accepts text, images and PDFs; Claude Opus 4 accepts text, images and PDFs; Gemini 2.0 Flash accepts text, images, PDFs, audio and video. Gemini 2.0 Flash handles the widest range of inputs.

Are any of these open source?

No. Claude Sonnet 3.5 v2, Claude Opus 4 and Gemini 2.0 Flash are proprietary and only available through APIs and apps.

Which is newer?

Claude Opus 4 is the newest, released May 22, 2025. Gemini 2.0 Flash came out Dec 11, 2024; Claude Sonnet 3.5 v2 came out Oct 22, 2024. Knowledge cutoff: Claude Sonnet 3.5 v2 Apr 30, 2024, Claude Opus 4 Mar 31, 2025, Gemini 2.0 Flash Jun 2024.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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