Model comparison
Claude Opus 5 vs GPT-5.3 Codex
Head-to-head evidence from 12 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Opus 5 #1 (Estimated); GPT-5.3 Codex #29 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Opus 5 and GPT-5.3 Codex share 12 comparable benchmark results. 2 of 8 categories are comparable. 67 results are unique to Claude Opus 5; 9 to GPT-5.3 Codex.
Updated July 24, 2026- Shared results
- 12
- Claude Opus 5 only
- 67
- GPT-5.3 Codex only
- 9
- Comparable categories
- 2 / 8
Pick Claude Opus 5 if you want the stronger benchmark profile. GPT-5.3 Codex only becomes the better choice if you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 12 shared benchmark results across 4 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Opus 5 is clearly ahead on the BenchAlign aggregate, 85.88 to 65.81. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Opus 5's sharpest advantage is in coding, where it averages 89.5 against 67.2. The single biggest benchmark swing on the page is SWE-bench Pro, 79.2% to 56.8%.
Claude Opus 5 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $1.75 input / $14.00 output per 1M tokens for GPT-5.3 Codex.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Opus 5 | Δ | GPT-5.3 Codex |
|---|---|---|---|
| Coding | Claude Opus 589.5 | Margin← 22.3 | GPT-5.3 Codex67.2 |
| Agentic | Claude Opus 590.8 | Margin← 19.4 | GPT-5.3 Codex71.4 |
| Reasoning | Claude Opus 590.4 | MarginNo overlap | GPT-5.3 CodexNot measured |
| Knowledge | Claude Opus 564.7 | MarginNo overlap | GPT-5.3 CodexNot measured |
| Multimodal | Claude Opus 566.9 | MarginNo overlap | GPT-5.3 CodexNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Pro
CodingA 79.2%B 56.8%Winner: Claude Opus 5Δ 22.4SWE-bench Pro: Claude Opus 5 scored 79.2%; GPT-5.3 Codex scored 56.8%. Claude Opus 5 wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 96%B 85%Winner: Claude Opus 5Δ 11SWE-bench Verified: Claude Opus 5 scored 96%; GPT-5.3 Codex scored 85%. Claude Opus 5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Opus 5 | GPT-5.3 Codex | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Opus 5$5 input / $25 output | GPT-5.3 Codex$1.75 input / $14 output | GPT-5.3 Codex has the lower combined listed price. |
| Generation speedtokens per second | Claude Opus 5Not available | GPT-5.3 Codex79 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Opus 5Not available | GPT-5.3 Codex88.26 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Opus 5Not available | GPT-5.3 Codex400K | A complete context comparison is not available. |
Benchmark Deep Dive
AgenticClaude Opus 5 wins29 benchmarks
| Benchmark | Claude Opus 5 | GPT-5.3 Codex | Result |
|---|---|---|---|
| FrontierBench v0.1Source | 43.3% | — | Not comparable |
| BrowseCompSource | 90.8% | — | Not comparable |
| HLE w/ toolsSource | 64.7% | — | Not comparable |
| DeepSearchQASource | 95.0% | — | Not comparable |
| DRACOSource | 88.6% | — | Not comparable |
| BrowseComp (10-agent, prerelease)Source | 93.6% | — | Not comparable |
| OSWorld 2.0Source | 70.6% | — | Not comparable |
| MCP AtlasSource | 85.8% | — | Not comparable |
| MCP-Atlas claim coverageSource | 89.1% | — | Not comparable |
| LAB all-pass (Anthropic harness)Source | 23.58% | — | Not comparable |
| LAB criterion-pass (Anthropic harness)Source | 93.74% | — | Not comparable |
| LAB all-pass (Harvey held-out)Source | 11.7% | — | Not comparable |
| LAB criterion-pass (Harvey held-out)Source | 94.1% | — | Not comparable |
| GDPval-AASource | 1861 | — | Not comparable |
| Toolathlon-VerifiedSource | 80.6% | — | Not comparable |
| Toolathlon Verified Pass@3Source | 87.0% | — | Not comparable |
| Toolathlon Verified Pass³Source | 73.1% | — | Not comparable |
| Toolathlon Verified avg. turnsSource | 23.5 turns | — | Not comparable |
| AutomationBenchSource | 26.0% | — | Not comparable |
| AA Agentic IndexSource | 55.3% | — | Not comparable |
| GDPval-AASource | 68.0% | — | Not comparable |
| AA Tau3 BankingSource | 30.3% | — | Not comparable |
| AA BriefcaseSource | 1720 | — | Not comparable |
| aaTerminalBench21Source | 89.1% | — | Not comparable |
| Terminal-Bench 2.0Source | — | 77.3% | Not comparable |
| OSWorld-VerifiedSource | — | 64.7% | Not comparable |
| τ²-bench resultsSource | — | 86% | Not comparable |
| Gert LabsSource | — | 57.47% | Not comparable |
| JobBenchSource | — | 33.7% | Not comparable |
CodingClaude Opus 5 wins14 benchmarks
| Benchmark | Claude Opus 5 | GPT-5.3 Codex | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 96% | 85% | Claude Opus 5 leads |
| SWE-bench ProSource | 79.2% | 56.8% | Claude Opus 5 leads |
| SWE MultilingualSource | 89.5% | — | Not comparable |
| SWE MultimodalSource | 59.4% | — | Not comparable |
| deepSweSource | 68.8% | — | Not comparable |
| FrontierCode 1.1 MainSource | 53.4% | — | Not comparable |
| FrontierCode 1.1 ExtendedSource | 63.6% | — | Not comparable |
| ProgramBench (episode 1)Source | 83.0% | — | Not comparable |
| ProgramBenchSource | 93.0% | — | Not comparable |
| cursorBench32Source | 70.0% | — | Not comparable |
| AA Coding IndexSource | 78.0% | — | Not comparable |
| AA-SciCodeSource | 55.7% | 53.2% | Claude Opus 5 leads |
| SWE-RebenchSource | — | 58.2% | Not comparable |
| Vibe Code BenchSource | — | 61.77% | Not comparable |
Reasoning5 benchmarks
Knowledge21 benchmarks
| Benchmark | Claude Opus 5 | GPT-5.3 Codex | Result |
|---|---|---|---|
| HLESource | 64.7% | — | Not comparable |
| HLE w/o toolsSource | 56.3% | — | Not comparable |
| HealthBench (raw)Source | 67.1% | — | Not comparable |
| HealthBench (length-adjusted)Source | 57.8% | — | Not comparable |
| HealthBench ProfessionalSource | 59.8% | — | Not comparable |
| HealthBench Professional (raw)Source | 73.4% | — | Not comparable |
| BioMysteryBench (human-solvable)Source | 90.1% | — | Not comparable |
| BioMysteryBench (human-difficult)Source | 49.4% | — | Not comparable |
| SpatialBench VerifiedSource | 72.5% | — | Not comparable |
| SingleCellBenchSource | 60.6% | — | Not comparable |
| ProteinGym HardSource | 47.7% | — | Not comparable |
| Protein DesignSource | 42.5% | — | Not comparable |
| Organic chemistry V2Source | 61.6% | — | Not comparable |
| Protocols (troubleshooting)Source | 61.1% | — | Not comparable |
| Protocols (understanding)Source | 78.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 60.7% | 44.3% | Claude Opus 5 leads |
| AA-GPQA DiamondSource | 93.2% | 91.5% | Claude Opus 5 leads |
| AA-HLESource | 52.6% | 39.9% | Claude Opus 5 leads |
| AA-Omniscience IndexSource | 31.3% | 9.9% | Claude Opus 5 leads |
| AA-Omniscience AccuracySource | 54.2% | 51.8% | Claude Opus 5 leads |
| AA-Omniscience Hallucination RateSource | 50.1% | 86.9% | Claude Opus 5 leads |
Math5 benchmarks
Multilingual3 benchmarks
Multimodal10 benchmarks
| Benchmark | Claude Opus 5 | GPT-5.3 Codex | Result |
|---|---|---|---|
| Chartography (no tools)Source | 29.6% | — | Not comparable |
| Chartography (tools)Source | 83.0% | — | Not comparable |
| BenchCAD Vision2Code (no tools)Source | 0.366 | — | Not comparable |
| BenchCAD Vision2Code (tools)Source | 0.821 | — | Not comparable |
| GDP.pdf (no tools)Source | 83.4% | — | Not comparable |
| GDP.pdf (tools)Source | 85.5% | — | Not comparable |
| OfficeQASource | 78.1% | — | Not comparable |
| OfficeQA ProSource | 66.9% | — | Not comparable |
| AA-MMMU-ProSource | 84.7% | 78.5% | Claude Opus 5 leads |
| Design Arena WebsiteSource | — | 1193 | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Claude Opus 5 | GPT-5.3 Codex | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 75.4% | Not comparable |
Frequently Asked Questions (3)
Which is better, Claude Opus 5 or GPT-5.3 Codex?
Claude Opus 5 is ahead on BenchLM's BenchAlign leaderboard, 85.88 to 65.81. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 79.2% and 56.8%.
Which is better for coding, Claude Opus 5 or GPT-5.3 Codex?
Claude Opus 5 has the edge for coding in this comparison, averaging 89.5 versus 67.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Claude Opus 5 or GPT-5.3 Codex?
Claude Opus 5 has the edge for agentic tasks in this comparison, averaging 90.8 versus 71.4. GPT-5.3 Codex stays close enough that the answer can still flip depending on your workload.