Data points: 39
Model compare
The readout for FLUX.2 Klein 4B and GPT-5.1, before the detailed comparison sheet.
Weighted outcome: GPT-5.1. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Decision read
GPT-5.1
GPT-5.1 has the higher weighted result; Model A / B score 0 to 100.
Evidence depth
39 data points
Includes 0 benchmark rows, 0 audit samples, and 3 provider examples.
Selection signal
Start with GPT-5.1
The charts below split 3 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 FLUX.2 Klein 4B and GPT-5.1: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Model compare | FLUX.2 Klein 4B | GPT-5.1 |
|---|---|---|
| Overall leader | Contender | Leading |
| Weighted overall score | 0.0 pts | 100.0 pts |
| Benchmark category leads | 0 categories | 0 categories |
| Operational advantages | No data | Cheapest input price, Free providers, Provider coverage |
| Context window | 41.0K tokens | 400K tokens |
| Max output | No data | 128K tokens |
| Modalities | Input TextImage Output Image |
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 | FLUX.2 Klein 4B | GPT-5.1 |
|---|---|---|
| Developer | Black Forest Labs | OpenAI |
| Released | Jan 2026 | Nov 2025 |
| Parameters | 4B | No data |
| Tokenizer | Other | GPT |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | black-forest-labs/flux.2-klein-4b | openai/gpt-5.1 |
| References | No data | No data |
This report only uses LMSpeed data for FLUX.2 Klein 4B and GPT-5.1: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
FLUX.2 Klein 4B
FLUX.2 Klein 4B does not clearly lead in the benchmark or operational dimensions shared by both models.
GPT-5.1
GPT-5.1 has these operational advantages: Cheapest input price, Free providers, 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
FLUX.2 Klein 4B
-
Avg. score
GPT-5.1
52
GPT-5.1
GPT-5.1
GPT-5.1
GPT-5.1
GPT-5.1
No data
No data
GPT-5.1
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
No shared professional benchmark scores are available yet.
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | FLUX.2 Klein 4B | GPT-5.1 |
|---|---|---|
| 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 | FLUX.2 Klein 4B | GPT-5.1 |
|---|---|---|
0 tests | FLUX.2 Klein 4B speed / latency N/A / N/A input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
0 tests | FLUX.2 Klein 4B flux-2-klein-4b speed / latency N/A / N/A input / output $60.00/M/$60.00/M | GPT-5.1 gpt-5.1-2025-11-13 speed / latency N/A / N/A input / output $6.00/M |
0 tests | FLUX.2 Klein 4B speed / latency N/A / N/A input / output No data | GPT-5.1 speed / latency N/A / N/A input / output No data |
Weighted outcome: GPT-5.1. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.
Input
Output
| Features | Text inputImage inputImage output | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning |
|---|
