ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Claude Opus 4.1 vs Claude Sonnet 3.5 v2

Claude Opus 4.1 comes out ahead, 49 to 44 on our weighted score, though Claude Sonnet 3.5 v2 is 5× cheaper per token.

  1. Our pick

    Anthropic

    Claude Opus 4.1

    Released Aug 5, 2025

    49/100
    • ECI144.1
    • Price$15.00 / $75.00
    • Context200K
    Full specs Remove Claude Opus 4.1

  2. 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

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Claude Opus 4.1 is our pick

Claude Opus 4.1 is the better all-round choice, scoring 49/100 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 4.1Capabilities Index (ECI): Claude Opus 4.1 144.1 · Claude Sonnet 3.5 v2 133.5
  • Lowest priceClaude Sonnet 3.5 v2Claude Sonnet 3.5 v2 $6.00 · Claude Opus 4.1 $30.00 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameClaude Opus 4.1 200,000 · Claude Sonnet 3.5 v2 200,000 tokens
  • Widest inputsSame inputsClaude Opus 4.1: Text, Images, PDFs · Claude Sonnet 3.5 v2: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightClaude Opus 4.1Claude Sonnet 3.5 v2
CapabilityCapabilities Index (ECI)50%7157
Price25%013
Inputs & features15%7060
Context window10%3232
Overall100%49/10044/100
02 — Side by side

Every spec in one table

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

Claude Opus 4.1 vs Claude Sonnet 3.5 v2 specifications side by side
SpecificationClaude Opus 4.1AnthropicClaude Sonnet 3.5 v2Anthropic
Capability
Capabilities Index (ECI)144.1 (best)133.5
ECI rank#81 of 148 (best)#119 of 148
GPQA DiamondGraduate-level science questions77.3% (best)55.3%
FrontierMath Tiers 1–3Research-level mathematics12.6%—
OTIS Mock AIME 2024–2025Competition mathematics68.9% (best)8.5%
SWE-bench VerifiedFixing real GitHub issues73.4%—
Price per million tokens
Input$15.00$3.00 (best)
Output$75.00$15.00 (best)
Cached input——
Blended (3:1)$30.00$6.00 (best)
Long-context rateSame rateSame rate
Price sourceMedian of 14 providersMedian of 1 providers
Limits
Context window200,000 tokens200,000 tokens
Max output32,000 tokens (best)8,192 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningYesNo
Tool callingYesYes
Structured outputNoNo
Availability
WeightsProprietaryProprietary
API model ID——
API providers14 (best)1
ReleasedAug 5, 2025Oct 22, 2024
Knowledge cutoffMar 31, 2025Apr 30, 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 Opus 4.1$300.00
  • Claude Sonnet 3.5 v2$60.00
04 — Questions

Which should you choose?

Which is better: Claude Opus 4.1 or Claude Sonnet 3.5 v2?

Claude Opus 4.1 is the better all-round choice, scoring 49/100 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 Opus 4.1 or Claude Sonnet 3.5 v2?

Claude Sonnet 3.5 v2 is cheaper at $3.00 input / $15.00 output per million tokens (median across 1 API provider). Claude Opus 4.1 costs $15.00 input / $75.00 output per million tokens (median across 14 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 4.1 (5× as much).

Which scores higher on benchmarks?

Claude Opus 4.1 scores higher on the Capabilities Index (ECI): Claude Opus 4.1 144.1 (#81 of 148) and Claude Sonnet 3.5 v2 133.5 (#119 of 148). Their confidence ranges do not overlap (141.6–146.0 vs 129.2–137.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 4.1 77.3%, Claude Sonnet 3.5 v2 55.3%; OTIS Mock AIME 2024–2025 — Claude Opus 4.1 68.9%, 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 4.1 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 Opus 4.1 and Claude Sonnet 3.5 v2 share the same 200,000-token context window. Maximum output per response: Claude Opus 4.1 up to 32,000, Claude Sonnet 3.5 v2 up to 8,192 tokens.

Which can read images, PDFs, audio or video?

Claude Opus 4.1 accepts text, images and PDFs; Claude Sonnet 3.5 v2 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. Claude Opus 4.1 and Claude Sonnet 3.5 v2 are proprietary and only available through APIs and apps.

Which is newer?

Claude Opus 4.1 is the newest, released Aug 5, 2025. Claude Sonnet 3.5 v2 came out Oct 22, 2024. Knowledge cutoff: Claude Opus 4.1 Mar 31, 2025, Claude Sonnet 3.5 v2 Apr 30, 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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