FLUX.2 Klein 4BvsClaude Opus 5

FLUX.2 Klein 4B leads the overall Podium Score by 5.1 points (86.5 vs 81.4).Category wins: FLUX.2 Klein 4B 1 — 3 Claude Opus 5.FLUX.2 Klein 4B is the cheaper pick ($0.01/M vs $25/M per 1M output tokens). FLUX.2 Klein 4B is faster (90 t/s vs 60 t/s).

Open in Compare Tool →View FLUX.2 Klein 4BView Claude Opus 5
FLUX.2 Klein 4BDrag slider or hover to compareClaude Opus 5
Claude Opus 5
81.4
Coding: 70.4 · Speed: 60 t/s
Output Price: $25/M
FLUX.2 Klein 4B
86.5
Coding: 0.0 · Speed: 90 t/s
Output Price: $0.01/M
Quick VerdictAggregated 2026 Benchmark Analysis

FLUX.2 Klein 4B is rated higher overall with a Podium Score of 86.5 (vs 81.4 for Claude Opus 5). In head-to-head domain evaluations, Claude Opus 5 outperforms in 3 of 7 benchmark categories.

Coding & Engineering
Claude Opus 5 (70.4)
Inference Speed
FLUX.2 Klein 4B (90 t/s)
Cost Efficiency
FLUX.2 Klein 4B ($0.01/M)
API Price / 1M (in · out)
FLUX.2 Klein 4B $0.01/M · $0.01/M — Claude Opus 5 $5/M · $25/M

Choose FLUX.2 Klein 4B for knowledge and factual QA, and Claude Opus 5 for long documents and large codebases.

MetricFLUX.2 Klein 4BClaude Opus 5
Podium Score86.5 ▲81.4
Arena Elo13801492 ▲
Intelligence Index87.0 ▲61.0
Coding0.070.4 ▲
Math0.0—
Reasoning25.082.3 ▲
Agentic18.0—
Knowledge42.0 ▲37.1
Multimodal90.0—
Long-context35.099.2 ▲
Output speed90 t/s ▲60 t/s
Output price$0.01/M ▲$25/M
Context window32K1000K ▲
Scores aggregated from five independent leaderboards. See Methodology. More head-to-heads: FLUX.2 Klein 4B vs Claude Mythos · FLUX.2 Klein 4B vs Claude 5.5 Sonnet · FLUX.2 Klein 4B vs Kimi K3.1 Pro · FLUX.2 Klein 4B vs Eleven Multilingual v3
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