# GPT-5.3 Codex vs GPT-5.6 Terra

> Side-by-side benchmark comparison for GPT-5.3 Codex and GPT-5.6 Terra across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-gpt-5-6-terra
- Last updated: September 24, 2026

- Shared sourced benchmarks: 3
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.3 Codex and GPT-5.6 Terra share only 3 sourced benchmark rows.

## Summary

- Only 3 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- GPT-5.6 Terra has the lower published output-token price.
- GPT-5.6 Terra has the larger published context window at 1.05M.

## Model Snapshot

| Property | GPT-5.3 Codex | GPT-5.6 Terra |
|----------|----------|----------|
| Creator | OpenAI | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 1.05M |
| Independent public score (not head-to-head) | 62.18 | 72.58 |
| Benchmarks Covered | 10 | 32 |
| Pricing (input/output) | $1.75 / $14.00 | $2.00 / $12.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 54.2 (Estimated · #31/105)
- GPT-5.6 Terra public-lane score: 59.5 (Supported · #18/105)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | Coming soon | Coming soon |
| OSWorld-Verified | 64.7% | Coming soon | Coming soon |
| Gert Labs | 57.47% | Coming soon | Coming soon |
| JobBench | 33.7% | Coming soon | Coming soon |
| Terminal-Bench 3.0 | Coming soon | 20.8% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 87.4% | Coming soon |
| BrowseComp | Coming soon | 87.5% | Coming soon |
| OSWorld 2.0 | Coming soon | 50.2% | Coming soon |
| CyberGym | Coming soon | 81.8% | Coming soon |
| ExploitGym | Coming soon | 23.2% | Coming soon |
| Toolathlon | Coming soon | 53.1% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 77.5% | Coming soon |
| ApprenticeBench | Coming soon | 16% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 55.9 (Supported · #26/135)
- GPT-5.6 Terra public-lane score: 64.7 (Supported · #8/135)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | Coming soon | Coming soon |
| SWE-bench Pro | 56.8% | 63.4% | GPT-5.6 Terra |
| SWE-Rebench | 58.2% | Coming soon | Coming soon |
| Vibe Code Bench | 61.77% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.3% | 85.9% | GPT-5.3 Codex |
| SWE-bench (Vals) | 78.0% | 95.4% | GPT-5.6 Terra |
| Terminal-Bench 2.1 | Coming soon | 87.4% | Coming soon |
| DeepSWE | Coming soon | 69.6% | Coming soon |
| FrontierCode 1.1 Extended | Coming soon | 55.8% | Coming soon |
| cursorBench32 | Coming soon | 64.9% | Coming soon |
| VulcanBench v3 | Coming soon | 87.0% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 79.3 (Unranked · 2 rankable rows)
- GPT-5.6 Terra public-lane score: 65.4 (#12/19)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | Coming soon | 83.9% | Coming soon |
| ARC-AGI-3 | Coming soon | 0.8% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 75.7 (Unranked · 1 rankable row)
- GPT-5.6 Terra public-lane score: 77.2 (#16/50)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | Coming soon | 80.7% | Coming soon |
| MMMU-Pro w/ Python | Coming soon | 82% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 64.3 (Estimated · #26/158)
- GPT-5.6 Terra public-lane score: 71.1 (Supported · #9/158)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| GPQA | Coming soon | 92.9% | Coming soon |
| GPQA-D | Coming soon | 92.9% | Coming soon |
| HLE-Verified | Coming soon | 51.1% | Coming soon |
| LABBench2 | Coming soon | 81.2% | Coming soon |
| HealthBench Professional | Coming soon | 57.7% | Coming soon |
| HealthBench Hard | Coming soon | 32.7% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 90.9% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 86.7% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 91.2 (#14/124)
- GPT-5.6 Terra public-lane score: 85.7 (#35/124)

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 96.8 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.3 Codex | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | Coming soon | 84.9% | Coming soon |
| FrontierMath v2 (Tiers 1-3) | Coming soon | 84.900% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 68.300% | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.3 Codex and GPT-5.6 Terra?

Not yet. The models share only 3 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [GPT-5.3 Codex vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-vs-gpt-5-3-codex-spark)
- [GPT-5.6 Terra vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-gpt-5-6-terra)
- [GPT-5.3 Codex vs GPT-5.6 Sol](/compare/gpt-5-3-codex-vs-gpt-5-6-sol)
- [GPT-5.6 Terra vs GPT-5.6 Sol](/compare/gpt-5-6-sol-vs-gpt-5-6-terra)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [GPT-5.6 Terra profile](/models/gpt-5-6-terra)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)