Compare / head-to-head
Claude Opus 4.8vs
GPT-5-Codex
Claude Opus 4.8 leads 2 of 2 shared benchmarks. GPT-5-Codex is 2.7x cheaper per token. Claude Opus 4.8 has the larger context window (1M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
2 – 0
Claude Opus 4.8 leads
Cheaper per token
GPT-5-Codex
2.7x cheaper, input + output
Larger context
Claude Opus 4.8
1M tokens
Providers
2 providers
Anthropic · OpenAI
Claude Opus 4.8
Anthropic · released 2026-05-28
textvision
GPT-5-Codex
OpenAI · released 2025-09-15
textvision
Quality
Benchmark matrix
2 shared · 38 only Claude Opus 4.8 · 0 only GPT-5-Codex| Benchmark | Claude Opus 4.8 | GPT-5-Codex | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 2 | ||||
| SWE-bench Verified | 88.6% ↗ | 74.5% ↗ | +14.1 pt | Claude Opus 4.8 |
| WeirdML (Håvard Tveit Ihle) | 82.9% ↗ | 54.5% ↗ | +28.4 pt | Claude Opus 4.8 |
| Only Claude Opus 4.8 reports · 38 | ||||
| GPQA Diamond | 93.6% ↗ | not reported | — | — |
| AIME 2026 | 100% ↗matharena ⚠ | not reported | — | — |
| Humanity's Last Exam (no tools) | 49.8% ↗ | not reported | — | — |
| LMArena Elo | 1452.7 ↗ | not reported | — | — |
| APEX-Agents (Mercor) | 48.9% ↗ | not reported | — | — |
| BrowseComp | 84.3% ↗ | not reported | — | — |
| Chess Puzzles (Epoch AI run) | 34% ↗epoch run | not reported | — | — |
| DeepSWE v1.1 (Datacurve) | 59% ↗ | not reported | — | — |
| EBR-bench (Epoch AI run) | 28.6% ↗epoch run | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 56.1% ↗epoch run | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 80% ↗epoch run | not reported | — | — |
| Furniture Assembly (Epoch AI run) | 42.5% ↗epoch run | not reported | — | — |
| GSO Opt@1 (GSO) | 47.1% ↗ | not reported | — | — |
| Humanity's Last Exam (with tools) | 57.9% ↗ | not reported | — | — |
| LiveBench Agentic Coding (LiveBench) | 50.5% ↗ | not reported | — | — |
| LiveBench Coding (LiveBench) | 81.8% ↗ | not reported | — | — |
| LiveBench Data Analysis (LiveBench) | 66% ↗ | not reported | — | — |
| LiveBench Instruction Following (LiveBench) | 72% ↗ | not reported | — | — |
| LiveBench Language (LiveBench) | 79.7% ↗ | not reported | — | — |
| LiveBench Mathematics (LiveBench) | 94.3% ↗ | not reported | — | — |
| LiveBench Reasoning (LiveBench) | 89.2% ↗ | not reported | — | — |
| LMArena Agent (LMArena) | 0.0664 ↗ | not reported | — | — |
| LMArena Vision (LMArena) | 1286.4 ↗ | not reported | — | — |
| LMArena WebDev (LMArena) | 1555.5 ↗ | not reported | — | — |
| Mystery Game Puzzles (Epoch AI run) | 36% ↗epoch run | not reported | — | — |
| OSWorld-Verified | 83.4% ↗ | not reported | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 98.3% ↗epoch run | not reported | — | — |
| SAGE (Vals AI) | 54.8% ↗ | not reported | — | — |
| SimpleBench (SimpleBench) | 64.8% ↗ | not reported | — | — |
| SimpleQA Verified | 53% ↗epoch run | not reported | — | — |
| SWE-bench Multilingual | 84.4% ↗ | not reported | — | — |
| SWE-bench Multimodal | 38.4% ↗ | not reported | — | — |
| SWE-Bench Pro | 69.2% ↗ | not reported | — | — |
| tau2-bench Banking Knowledge (Sierra) | 39.7% ↗ | not reported | — | — |
| Terminal-Bench 2.1 | 74.6% ↗ | not reported | — | — |
| Terminal-Bench 4.0 (Vals AI) | 23.2% ↗ | not reported | — | — |
| Toolathlon-Verified (HKUST) | 76.2% ↗ | not reported | — | — |
| Vending-Bench 2 (Andon Labs) | 5787.43 ↗ | not reported | — | — |
| Only GPT-5-Codex reports · 0 | ||||
| GPT-5-Codex reports nothing Claude Opus 4.8 does not. | ||||
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Claude Opus 4.8 minus GPT-5-Codex in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Claude Opus 4.8 | GPT-5-Codex | Edge |
|---|---|---|---|
| Context window | 1M tokens | 400K tokens | Claude Opus 4.8 |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $5 ↗ | $1.25 ↗ | GPT-5-Codex |
| Output price / 1M | $25 ↗ | $10 ↗ | GPT-5-Codex |
| Cached input / 1M | $0.5 ↗ | $0.125 ↗ | GPT-5-Codex |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $30 | $11.25 | GPT-5-Codex |
| Modalities | text · vision | text · vision | Tie |
| Released | 2026-05-28 | 2025-09-15 | — |
| Cited benchmark scores | 47 | 2 | — |
Reliability
Provider status
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Which one wins on your data?
Public benchmarks are a starting point. Run Claude Opus 4.8 and GPT-5-Codex on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.