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Model Comparison

Claude Opus 5 vs o3Which Is Better in 2026?

Claude Opus 5 logoAnthropic•OpenAI: o3 logoOpenAI

Claude Opus 5 vs o3: which should you choose in 2026?

Claude Opus 5 (by Anthropic) and o3 (by OpenAI) are compared below. Here is how they stack up on benchmarks, price, and capabilities, and which one to pick in 2026.

Claude Opus 5 outperforms in 1 benchmark (OSWorld-Verified), while o3 is better at 0 benchmarks.

Claude Opus 5 leads every shared, protocol-compatible benchmark shown here.

o3 is about 2.9× cheaper on a blended 3:1 input/output basis ($3.50 vs $10.00 per 1M tokens).

Claude Opus 5 has the larger context window (1,000,000 tokens vs 200,000 tokens).

Choose Claude Opus 5 if…

  • • you want the model leading more of the 1 shared benchmark
  • • you work with longer documents, transcripts, or codebases

Choose o3 if…

  • • lower blended API cost matters for your workload

The benchmark count includes only results measured with a matching benchmark version and protocol. Arena scores are shown separately. Missing, preliminary, and incompatible data is not treated as a controlled win. Published point-score comparisons are labeled separately when protocol details are incomplete. For text-output models, the verdict also compares token pricing and context windows.

Chat with both models
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Performance benchmarks

Every value links to its source. A dash means that no reviewed result is available for that exact model and protocol.

Claude Opus 5 and o3 benchmark results
BenchmarkClaude Opus 5o3
AutomationBench-AA

A 657-task benchmark of multi-step work across simulated SaaS applications in six business domains. The Artificial Analysis protocol reports a guardrail-aware score and is distinct from both the public Zapier split and the unrelated dynamic AutoBench framework.

Guardrail-aware score

——
BrowseComp

A benchmark of difficult, verifiable information-seeking questions designed to measure an agent's ability to locate hard-to-find facts through web browsing.

Accuracy

——
OSWorld-Verified

A verified computer-use benchmark in which multimodal agents operate desktop applications and are graded from the resulting environment state.

Mean task reward

83.4%
OSWorld
23.0%
OSWorld
DeepSWE 1.1

A long-horizon software-engineering benchmark with 113 original tasks graded by hand-written tests.

Pass@1

74.0%±4.0
DataCurve
—
SWE-Bench Verified

A human-validated subset of real GitHub issues used to measure whether a coding agent can produce repository patches that resolve the associated tests.

Resolved

—
58.4%
SWE-bench
Terminal-Bench 2.1

Version 2.1 of the benchmark for completing realistic tasks in terminal environments. Harness, resource limits, and attempt count are part of the protocol.

Mean task success

——
AutoBench

A dynamic LLM evaluation framework in which models generate questions, answer them, and participate in reciprocal peer assessment. AutoBench is distinct from Zapier's AutomationBench.

Weighted peer-assessment score

——
GPQA Diamond

The highest-quality subset of Graduate-Level Google-Proof Q&A, designed to test expert-level scientific reasoning in biology, physics, and chemistry.

Accuracy

93.2%
Artificial Analysis
—
Humanity's Last Exam

A 2,500-question expert-level benchmark spanning dozens of academic fields. Tool-assisted and no-tools results are separate protocols and must not be merged.

Accuracy

54.9%
Artificial Analysis
—
LiveBench

A contamination-resistant benchmark refreshed on a fixed release cadence. Scores from different LiveBench releases must never be compared as the same protocol.

Mean of category averages

80.1%
LiveBench
—
Artificial Analysis Intelligence Index

Comprehensive comparison of AI models across intelligence, price, speed, and latency

Intelligence Index

—
65
artificialanalysis.ai

Benchmark sources

Reviewed evidence last updated 2026-08-09.

Pricing, capabilities, and model facts

Claude Opus 5 and o3 model facts
FeatureClaude Opus 5o3
Context & model facts
DeveloperAnthropicOpenAI
API providerClaude Opus 5OpenAI
Input context1,000,000 tokens200,000 tokens
Maximum output128,000 tokens100,000 tokens
Released——
Added to WritingmateJul 24, 2026Apr 16, 2025
LicenseNot availableNot available
Knowledge cutoff—2024-06-30
Capabilities
InputsText, Image, FileImage, Text, File
OutputsTextText
Provider endpoint accepts tool parametersYesYes
ReasoningYesYes
VisionYesYes
Image GenerationNoNo
Video GenerationNoNo
API pricing
Input (per 1M tokens)$5.00$2.00
Output (per 1M tokens)$25.00$8.00
Blended 3:1 input/output$10.00$3.50
API performance
p95 latencyNot measuredNot measured
Output throughputNot measuredNot measured
Writingmate shows API performance only when both models have enough observations from the same measurement window, prompt profile, and provider. Third-party latency values are not copied into this table.

Data sources

  • Writingmate model catalog (pricing, limits, and availability)

Catalog data last updated Jul 24, 2026.

Why Pay for Multiple Subscriptions?

Comparing Claude Opus 5 from Anthropic with o3 from OpenAI? Instead of managing separate API keys and subscriptions, get both with Writingmate.

Subscription-plan access for Claude Opus 5 and o3
PlanPriceClaude Opus 5o3AI ImagesAI Video
Writingmate Pro
Most popular
$20/moUltimate requiredIncludedNano Banana Pro, FLUX.2, DALL-E & moreSora 2, VEO 3.1
Writingmate Ultimate
Power users
$60/moIncludedIncludedNano Banana Pro, FLUX.2, DALL-E & moreSora 2, VEO 3.1
View Plans & Pricing

Claude Opus 5 vs o3 FAQ

Which is better, Claude Opus 5 or o3?

Claude Opus 5 outperforms in 1 benchmark (OSWorld-Verified), while o3 is better at 0 benchmarks. Claude Opus 5 leads every shared, protocol-compatible benchmark shown here. o3 is about 2.9× cheaper on a blended 3:1 input/output basis ($3.50 vs $10.00 per 1M tokens). Claude Opus 5 has the larger context window (1,000,000 tokens vs 200,000 tokens).

Which model is cheaper to use through an API?

o3 is about 2.9× cheaper on a blended 3:1 input/output basis ($3.50 vs $10.00 per 1M tokens).

Which model supports more context?

Claude Opus 5 has the larger context window (1,000,000 tokens vs 200,000 tokens).

Can I switch between Claude Opus 5 and o3?

Yes. Use the model selector on this page to open any current Writingmate model comparison. You can also run the same prompt with both models in Writingmate.