# DeepSeek V4 Flash vs GPT-5.3 Chat

> DeepSeek V4 Flash is the stronger model overall, scoring 53.6 to 42.1 on the Noometry Index.

- Canonical page: https://noometry.com/compare/deepseek-v4-flash-vs-gpt-5-3-chat
- Last updated: 2026-10-10
- Shared benchmarks: 18

## Summary

- They share 18 benchmarks with published results for both. DeepSeek V4 Flash scores higher in 8 categories and GPT-5.3 Chat in 0 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where DeepSeek V4 Flash leads 53.7 to 27.3.
- DeepSeek V4 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
- DeepSeek V4 Flash accepts more context: 1M tokens versus 128K.
- DeepSeek V4 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Noometry Index | 53.6 | 42.1 |
| Rank | 32 | 109 |
| Context | 1M | 128K |
| Input $/M | $0.15 | $1.75 |
| Output $/M | $0.60 | $14 |
| Weights | Open | Proprietary |

## Coding

- DeepSeek V4 Flash: 47.6 (#56)
- GPT-5.3 Chat: 40.8 (#124)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Coding | 1457 | 1408 |
| FrontierCode | 18.8% | — |
| LMArena WebDev | 1581 | — |
| SciCode | 49.9% | — |
| WeirdML | 63% | — |
| ALE-Bench | 1,306 | — |

## Reasoning

- DeepSeek V4 Flash: 53.7 (#25)
- GPT-5.3 Chat: 27.3 (#105)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Hard Prompts | 1443 | 1399 |
| ARC-AGI-2 | 61.4% | — |
| SimpleBench | 61.1% | — |
| Kagi LLM Benchmark | 52.2% | — |
| NYT Connections (extended) | 89.6% | — |
| ARC-AGI-1 | 89% | — |
| CritPt | 16.6% | — |
| Chess Puzzles | 33% | — |
| Mystery Game Puzzles | 34% | — |
| DTBench | 90.9% | — |
| LMCA | 41.7% | — |
| Epoch Capabilities Index | 154.51 | — |

## Math

- DeepSeek V4 Flash: 60.0 (#31)
- GPT-5.3 Chat: 35.4 (#146)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Math | 1427 | 1389 |
| FrontierMath (Tiers 1-3) | 57.5% | — |
| FrontierMath Tier 4 | 24.4% | — |
| MathArena Final-Answer Competitions | 76.5% | — |
| OTIS Mock AIME 2024-2025 | 94.4% | — |
| ProofBench | 56% | — |

## Knowledge

- DeepSeek V4 Flash: 55.5 (#43)
- GPT-5.3 Chat: 38.2 (#137)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Expert | 1441 | 1397 |
| GPQA Diamond | 91% | — |
| SimpleQA Verified | 33.6% | — |

## Multilingual

- DeepSeek V4 Flash: 53.2 (#71)
- GPT-5.3 Chat: 50.5 (#119)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Non-English | 1420 | 1383 |
| LMArena Chinese | 1467 | 1433 |
| LMArena French | 1438 | 1398 |
| LMArena German | 1418 | 1384 |
| LMArena Japanese | 1403 | 1351 |
| LMArena Korean | 1383 | 1347 |
| LMArena Russian | 1428 | 1400 |
| LMArena Spanish | 1437 | 1371 |

## Instruction Following

- DeepSeek V4 Flash: 75.1 (#76)
- GPT-5.3 Chat: 73.0 (#124)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Instruction Following | 1421 | 1378 |

## Long Context

- DeepSeek V4 Flash: 43.8 (#81)
- GPT-5.3 Chat: 42.6 (#115)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Longer Query | 1435 | 1396 |

## Writing & Preference

- DeepSeek V4 Flash: 64.0 (#59)
- GPT-5.3 Chat: 63.3 (#65)

| Benchmark | DeepSeek V4 Flash | GPT-5.3 Chat |
|---|---|---|
| LMArena Text | 1432 | 1389 |
| LMArena Creative Writing | 1403 | 1356 |
| EQ-Bench Creative Writing | 1559 | 1690 |
| LMArena Multi-Turn | 1449 | 1413 |

## FAQ

### Is DeepSeek V4 Flash better than GPT-5.3 Chat?

DeepSeek V4 Flash is the stronger model overall, scoring 53.6 to 42.1 on the Noometry Index.

### Which is cheaper, DeepSeek V4 Flash or GPT-5.3 Chat?

DeepSeek V4 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.

### Is DeepSeek V4 Flash or GPT-5.3 Chat better for coding?

DeepSeek V4 Flash scores higher on coding benchmarks: 47.6 versus 40.8 in the Noometry coding category.

### Which has the bigger context window?

DeepSeek V4 Flash does, with 1M tokens against 128K.

### How many benchmarks do DeepSeek V4 Flash and GPT-5.3 Chat share?

18 benchmarks have published results for both models. DeepSeek V4 Flash has 41 scored results on Noometry and GPT-5.3 Chat has 18.