# GPT-5.3 Codex vs Sonar

> GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 37.8 on the Noometry Index. Sonar costs 4.8× 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/gpt-5-3-codex-vs-sonar
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.3 Codex leads 48.5 to 35.1.
- Sonar is cheaper at $1 / $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 128K.

## Snapshot

| | GPT-5.3 Codex | Sonar |
|---|---|---|
| Provider | OpenAI | Perplexity |
| Noometry Index | 45.5 | 37.8 |
| Rank | 61 | 184 |
| Context | 400K | 128K |
| Input $/M | $1.75 | $1 |
| Output $/M | $14 | $1 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.3 Codex: 48.5 (#51)
- Sonar: 35.1 (#217)

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| SWE-bench Verified | 74.8% | — |
| LMArena WebDev | 1408 | — |
| WeirdML | 79.3% | — |
| LiveBench Coding | — | 35.1% |
| ALE-Bench | 1,655 | — |

## Agentic & Tool Use

- GPT-5.3 Codex: 47.8 (#9)
- Sonar: —

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |

## Reasoning

- GPT-5.3 Codex: —
- Sonar: 20.3 (#221)

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| LiveBench Reasoning | — | 46.3% |
| LiveBench Data Analysis | — | 37.9% |
| Epoch Capabilities Index | 156.84 | — |
| LiveBench | — | 46.9% |

## Math

- GPT-5.3 Codex: —
- Sonar: 31.3 (#197)

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| LiveBench Math | — | 41.6% |

## Instruction Following

- GPT-5.3 Codex: —
- Sonar: 71.5 (#146)

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| LiveBench Instruction Following | — | 76.2% |

## Writing & Preference

- GPT-5.3 Codex: —
- Sonar: 52.6 (#166)

| Benchmark | GPT-5.3 Codex | Sonar |
|---|---|---|
| LiveBench Language | — | 44.1% |

## FAQ

### Is GPT-5.3 Codex better than Sonar?

GPT-5.3 Codex is the stronger model overall, scoring 45.5 to 37.8 on the Noometry Index. Sonar costs 4.8× 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, GPT-5.3 Codex or Sonar?

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

### Is GPT-5.3 Codex or Sonar better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.5 versus 35.1 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.3 Codex does, with 400K tokens against 128K.

### How many benchmarks do GPT-5.3 Codex and Sonar share?

0 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Sonar has 7.