ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Claude Sonnet 3.5 v2 vs Claude Opus 4

Claude Opus 4 comes out ahead, 48 to 44 on our weighted score, though Claude Sonnet 3.5 v2 is 5× cheaper per token.

  1. Anthropic

    Claude Sonnet 3.5 v2

    Released Oct 22, 2024

    44/100
    • ECI133.5
    • Price$3.00 / $15.00
    • Context200K
    Full specs Remove Claude Sonnet 3.5 v2
  2. Our pick

    Anthropic

    Claude Opus 4

    Released May 22, 2025

    48/100
    • ECI142.7
    • Price$15.00 / $75.00
    • Context200K
    Full specs Remove Claude Opus 4

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Claude Opus 4 is our pick

Claude Opus 4 is the better all-round choice, scoring 48/100 against Claude Sonnet 3.5 v2 (44). It leads on capability and inputs & features. Claude Sonnet 3.5 v2 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Opus 4Capabilities Index (ECI): Claude Opus 4 142.7 · 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)
  • Longest contextAbout the sameClaude Sonnet 3.5 v2 200,000 · Claude Opus 4 200,000 tokens
  • Widest inputsSame inputsClaude Sonnet 3.5 v2: Text, Images, PDFs · Claude Opus 4: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightClaude Sonnet 3.5 v2Claude Opus 4
CapabilityCapabilities Index (ECI)50%5769
Price25%130
Inputs & features15%6070
Context window10%3232
Overall100%44/10048/100
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 specifications side by side
SpecificationClaude Sonnet 3.5 v2AnthropicClaude Opus 4Anthropic
Capability
Capabilities Index (ECI)133.5142.7 (best)
ECI rank#119 of 148#87 of 148 (best)
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 tokens
Max output8,192 tokens32,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningNoYes
Tool callingYesYes
Structured outputNoNo
Availability
WeightsProprietaryProprietary
API model ID——
API providers15 (best)
ReleasedOct 22, 2024May 22, 2025
Knowledge cutoffApr 30, 2024Mar 31, 2025
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
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 3.5 v2 or Claude Opus 4?

Claude Opus 4 is the better all-round choice, scoring 48/100 against Claude Sonnet 3.5 v2 (44). It leads on capability and inputs & features. Claude Sonnet 3.5 v2 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

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

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).

Which scores higher on benchmarks?

Claude Opus 4 scores higher on the Capabilities Index (ECI): Claude Opus 4 142.7 (#87 of 148) and Claude Sonnet 3.5 v2 133.5 (#119 of 148). Their confidence ranges do not overlap (140.2–144.2 vs 129.2–137.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 4 76.3%, Claude Sonnet 3.5 v2 55.3%; OTIS Mock AIME 2024–2025 — Claude Opus 4 64.4%, Claude Sonnet 3.5 v2 8.5%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Sonnet 3.5 v2 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. Both support tool calling for agent workflows.

Which has the bigger context window?

Claude Sonnet 3.5 v2 and Claude Opus 4 share the same 200,000-token context window. Maximum output per response: Claude Sonnet 3.5 v2 up to 8,192, Claude Opus 4 up to 32,000 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. They handle the same number of input types.

Are any of these open source?

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

Which is newer?

Claude Opus 4 is the newest, released May 22, 2025. 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.

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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