Data points: 114
Model compare
The readout for GPT-5.1 and GPT-5.3 Codex, before the detailed comparison sheet.
Weighted outcome: GPT-5.3 Codex. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Decision read
GPT-5.3 Codex
GPT-5.3 Codex has the higher weighted result; Model A / B score 12 to 88.
Evidence depth
114 data points
Includes 25 benchmark rows, 0 audit samples, and 7 provider examples.
Selection signal
Start with GPT-5.3 Codex
The charts below split 32 high-signal samples across speed, scores, and audit health.
Switch either side of this report to compare another model with the same LMSpeed data pipeline.
Select a different model to open a new comparison URL.
This report only uses LMSpeed data for GPT-5.1 and GPT-5.3 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | GPT-5.1 | GPT-5.3 Codex |
|---|---|---|
| Overall leader | Contender | Leading |
| Weighted overall score | 12.0 pts | 88.0 pts |
| Benchmark category leads | 0 categories | 5 categories |
| Operational advantages | Average speed, First-token latency, Free providers | Cheapest input price, Provider coverage |
| Context window | 400K tokens | 400K tokens |
| Max output | 128K tokens | 128K tokens |
| Modalities | Input ImageTextFile Output Text | Input |
The overall result weights benchmark capability categories at 80% and price, API speed/latency, and availability at 20%. Recent test volume does not affect the winner, and missing benchmark categories are excluded.
| Model compare | GPT-5.1 | GPT-5.3 Codex |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Released | Nov 2025 | Feb 2026 |
| Parameters | No data | No data |
| Tokenizer | GPT | GPT |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | openai/gpt-5.1 | openai/gpt-5.3-codex |
| References | No data | No data |
This report only uses LMSpeed data for GPT-5.1 and GPT-5.3 Codex: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
GPT-5.1
GPT-5.1 has these operational advantages: Average speed, First-token latency, Free providers.
GPT-5.3 Codex
GPT-5.3 Codex is stronger in benchmark categories (Agents, Coding, Reasoning, Knowledge, Instruction following) and operational dimensions (Cheapest input price, Provider coverage).
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.
Avg. score
GPT-5.1
52.1
Avg. score
GPT-5.3 Codex
56.7
GPT-5.3 Codex leads by 5.3
GPT-5.3 Codex leads by 9.8
GPT-5.3 Codex leads by 7.9
GPT-5.3 Codex leads by 1.1
GPT-5.1
No data
No data
GPT-5.3 Codex leads by 1.0
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
GPT-5.1
56.0
Rank #44/83 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner65.0
Rank #21/83 · confidence 1 · eval date 2026-02-05
GPT-5.1
111.6 tok/s
Rank #60/136 · confidence 4
GPT-5.3 Codex
winner130.7 tok/s
Rank #50/136 · confidence 4
GPT-5.1
winner35.90 s
Rank #113/136 · confidence 4
GPT-5.3 Codex
44.46 s
Rank #120/136 · confidence 4
GPT-5.1
winner35.90 s
Rank #128/136 · confidence 4
GPT-5.3 Codex
44.46 s
Rank #129/136 · confidence 4
GPT-5.1
winner$1.25/M
Rank #108/162 · confidence 4
GPT-5.3 Codex
$1.75/M
Rank #121/162 · confidence 4
GPT-5.1
winner$3.44/M
Rank #118/162 · confidence 4
GPT-5.3 Codex
$4.81/M
Rank #133/162 · confidence 4
GPT-5.1
winner$10.00/M
Rank #121/162 · confidence 4
GPT-5.3 Codex
$14.00/M
Rank #134/162 · confidence 4
GPT-5.1
winner75.0
Rank #3/89 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
74.0
Rank #5/89 · confidence 1 · eval date 2026-02-05
GPT-5.1
87.3%
Rank #32/187 · confidence 4
GPT-5.3 Codex
winner91.5%
Rank #11/187 · confidence 4
GPT-5.1
4.9
Rank #34/73 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner16.9
Rank #12/73 · confidence 1 · eval date 2026-02-05
GPT-5.1
26.5%
Rank #39/186 · confidence 4
GPT-5.3 Codex
winner39.9%
Rank #12/186 · confidence 4
GPT-5.1
24.6
Rank #18/33 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner61.8
Rank #4/33 · confidence 1 · eval date 2026-02-05
GPT-5.1
43.3%
Rank #41/184 · confidence 4
GPT-5.3 Codex
winner53.2%
Rank #10/184 · confidence 4
GPT-5.1
43.3
Rank #45/96 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner53.2
Rank #14/96 · confidence 1 · eval date 2026-02-05
GPT-5.1
37.6
Rank #31/90 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner51.8
Rank #8/90 · confidence 1 · eval date 2026-02-05
GPT-5.1
26.5
Rank #39/96 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner39.9
Rank #11/96 · confidence 1 · eval date 2026-02-05
GPT-5.1
87.3
Rank #36/96 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner91.5
Rank #12/96 · confidence 1 · eval date 2026-02-05
GPT-5.1
5.6
Rank #19/29 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner9.9
Rank #15/29 · confidence 1 · eval date 2026-02-05
GPT-5.1
36.9
Rank #42/99 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner44.3
Rank #16/99 · confidence 1 · eval date 2026-02-05
GPT-5.1
51.3
Rank #66/90 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner86.9
Rank #23/90 · confidence 1 · eval date 2026-02-05
GPT-5.1
75.5
Rank #23/57 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner78.5
Rank #14/57 · confidence 1 · eval date 2026-02-05
GPT-5.1
winner1220.0
Rank #37/65 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
1195.0
Rank #45/65 · confidence 1 · eval date 2026-02-05
GPT-5.1
72.9
Rank #30/86 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner75.4
Rank #21/86 · confidence 1 · eval date 2026-02-05
GPT-5.1
41.2
Rank #35/50 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner57.5
Rank #13/50 · confidence 1 · eval date 2026-02-05
GPT-5.1
81.9
Rank #52/84 · confidence 1 · eval date 2025-11-13
GPT-5.3 Codex
winner86.0
Rank #41/84 · confidence 1 · eval date 2026-02-05
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | GPT-5.1 | GPT-5.3 Codex |
|---|---|---|
| No completed audits are available from shared providers yet. | ||
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | GPT-5.1 | GPT-5.3 Codex |
|---|---|---|
35 tests | GPT-5.1 speed / latency N/A / N/A input / output No data | GPT-5.3 Codex speed / latency 38 tok/s / 4553ms input / output No data |
14 tests | GPT-5.1 speed / latency N/A / N/A input / output No data | GPT-5.3 Codex speed / latency 252 tok/s / 2196ms input / output No data |
10 tests | GPT-5.1 speed / latency 137 tok/s / 3299ms input / output No data | GPT-5.3 Codex speed / latency N/A / N/A input / output No data |
10 tests | GPT-5.1 speed / latency 179 tok/s / 6622ms input / output No data | GPT-5.3 Codex speed / latency 46 tok/s / 4380ms input / output No data |
10 tests | GPT-5.1 speed / latency N/A / N/A input / output No data | GPT-5.3 Codex speed / latency 57 tok/s / 2985ms input / output No data |
GPT-5.1 gpt-5.1 speed / latency No data input / output $0/request | GPT-5.3 Codex gpt-5.3-codex-spark speed / latency No data input / output $0.315/M | |
GPT-5.1 gpt-5.1-chat speed / latency No data input / output $0/request | GPT-5.3 Codex gpt-5.3-codex speed / latency No data input / output $0/request |
Weighted outcome: GPT-5.3 Codex. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Output
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
