Model comparison
Claude Haiku 5.5 vs GPT-5.1-Codex
Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 38.6 on the Noometry Index.
Last verified . 1 shared benchmarks.
Summary
- They share 1 benchmark with published results for both. Claude Haiku 5.5 scores higher in 2 categories and GPT-5.1-Codex in 0 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Haiku 5.5 leads 73.6 to 30.3.
- Claude Haiku 5.5 is cheaper at $0.10 / $0.50 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- Claude Haiku 5.5 accepts more context: 1M tokens versus 400K.
Side by side
| Claude Haiku 5.5 | GPT-5.1-Codex | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 49.5 | 38.6 |
| Released | 2026-10-07 | 2025-11-12 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 400K |
| Max output | 128K | 128K |
| Input $ / M tokens | $0.10 | $1.25 |
| Output $ / M tokens | $0.50 | $10 |
| Results tracked | 9 | 6 |
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Category by category
Coding Claude Haiku 5.5 leads
Claude Haiku 5.5: 49.2 (#50), GPT-5.1-Codex: 41.9 (#116)
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| LMArena WebDev | 1587 | 1337 |
| SWE-bench Verified (bash only) | — | 66% |
| ALE-Bench | — | 1,245 |
Agentic & Tool Use Not comparable
Claude Haiku 5.5: —, GPT-5.1-Codex: 38.0 (#33)
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| Terminal-Bench | — | 60.4% |
| METR Time Horizons | — | 70.8% |
Reasoning Not comparable
Claude Haiku 5.5: 35.2 (#69), GPT-5.1-Codex: —
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| NYT Connections (extended) | 65.7% | — |
| Mystery Game Puzzles | 30% | — |
Math Claude Haiku 5.5 leads
Claude Haiku 5.5: 73.6 (#18), GPT-5.1-Codex: 30.3 (#235)
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| FrontierMath (Tiers 1-3) | 75.1% | — |
| FrontierMath Tier 4 | 46.3% | — |
| OTIS Mock AIME 2024-2025 | 98.9% | — |
| ProofBench | — | 9% |
Knowledge Not comparable
Claude Haiku 5.5: 50.8 (#70), GPT-5.1-Codex: —
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| GPQA Diamond | 89.6% | — |
| SimpleQA Verified | 23.8% | — |
Multimodal Not comparable
Claude Haiku 5.5: 43.7 (#21), GPT-5.1-Codex: —
| Benchmark | Claude Haiku 5.5 | GPT-5.1-Codex |
|---|---|---|
| Furniture Assembly | 47.5% | — |
Frequently asked questions
Is Claude Haiku 5.5 better than GPT-5.1-Codex?
Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 38.6 on the Noometry Index.
Which is cheaper, Claude Haiku 5.5 or GPT-5.1-Codex?
Claude Haiku 5.5 is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is Claude Haiku 5.5 or GPT-5.1-Codex better for coding?
Claude Haiku 5.5 scores higher on coding benchmarks: 49.2 versus 41.9 in the Noometry coding category.
Which has the bigger context window?
Claude Haiku 5.5 does, with 1M tokens against 400K.
How many benchmarks do Claude Haiku 5.5 and GPT-5.1-Codex share?
1 benchmark has published results for both models. Claude Haiku 5.5 has 9 scored results on Noometry and GPT-5.1-Codex has 6.