# DeepSeek-V3.1-Terminus vs GPT-5.3 Codex

> GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 43.1 on the Noometry Index. DeepSeek-V3.1-Terminus costs 11× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/deepseek-v3-1-terminus-vs-gpt-5-3-codex
- Last updated: 2026-10-12
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. DeepSeek-V3.1-Terminus scores higher in 0 categories and GPT-5.3 Codex in 1 category; one gap is clear of the uncertainty.
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 42.0.
- DeepSeek-V3.1-Terminus is cheaper at $0.27 / $1 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- GPT-5.3 Codex accepts more context: 400K tokens versus 164K.
- DeepSeek-V3.1-Terminus has downloadable open weights; the other is API-only.

## Snapshot

| | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Noometry Index | 43.1 | 45.8 |
| Rank | 97 | 69 |
| Context | 164K | 400K |
| Input $/M | $0.27 | $1.75 |
| Output $/M | $1 | $14 |
| Weights | Open | Proprietary |

## Coding

- DeepSeek-V3.1-Terminus: 42.0 (#113)
- GPT-5.3 Codex: 48.6 (#56)

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| ALE-Bench | 745.17 | 1,655 |
| SWE-bench Verified | — | 74.8% |
| LMArena WebDev | — | 1409 |
| SciCode | 40.6% | — |
| WeirdML | — | 79.3% |
| LMArena Coding | 1426 | — |

## Agentic & Tool Use

- DeepSeek-V3.1-Terminus: —
- GPT-5.3 Codex: 48.0 (#9)

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| Terminal-Bench | — | 78.4% |
| METR Time Horizons | — | 74.5% |
| Vending-Bench 2 | — | 5,940 |

## Reasoning

- DeepSeek-V3.1-Terminus: 26.4 (#133)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| Kagi LLM Benchmark | 57.4% | — |
| CritPt | 1.7% | — |
| LMArena Hard Prompts | 1426 | — |
| DTBench | 81.3% | — |
| LMCA | 28.6% | — |
| Epoch Capabilities Index | — | 156.77 |

## Math

- DeepSeek-V3.1-Terminus: 38.5 (#137)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| LMArena Math | 1402 | — |

## Multilingual

- DeepSeek-V3.1-Terminus: 52.1 (#92)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| LMArena Non-English | 1407 | — |
| LMArena Russian | 1436 | — |

## Instruction Following

- DeepSeek-V3.1-Terminus: 74.0 (#106)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| LMArena Instruction Following | 1404 | — |

## Long Context

- DeepSeek-V3.1-Terminus: 43.4 (#97)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| LMArena Longer Query | 1421 | — |

## Writing & Preference

- DeepSeek-V3.1-Terminus: 61.0 (#92)
- GPT-5.3 Codex: —

| Benchmark | DeepSeek-V3.1-Terminus | GPT-5.3 Codex |
|---|---|---|
| LMArena Text | 1419 | — |
| LMArena Creative Writing | 1403 | — |
| LMArena Multi-Turn | 1411 | — |

## FAQ

### Is DeepSeek-V3.1-Terminus better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 43.1 on the Noometry Index. DeepSeek-V3.1-Terminus costs 11× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

### Which is cheaper, DeepSeek-V3.1-Terminus or GPT-5.3 Codex?

DeepSeek-V3.1-Terminus is cheaper. It lists at $0.27 per million input tokens and $1 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

### Is DeepSeek-V3.1-Terminus or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 42.0 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.3 Codex does, with 400K tokens against 164K.

### How many benchmarks do DeepSeek-V3.1-Terminus and GPT-5.3 Codex share?

1 benchmark has published results for both models. DeepSeek-V3.1-Terminus has 16 scored results on Noometry and GPT-5.3 Codex has 8.