Quick Take

Released in June 2026, these two models represent vastly different segments of the AI market. Google’s Gemma 4 12B is a non-reasoning, lightweight model focused on accessibility, while Anthropic’s Claude Fable 5 is a high-effort, adaptive reasoning powerhouse designed for complex problem-solving.

Benchmark Read

Claude Fable 5 consistently outperforms Gemma 4 12B across all measured benchmarks.

• Intelligence & Coding: Claude Fable 5 leads with an Intelligence index of 64.9 and a Coding index of 62, compared to Gemma 4 12B’s 19.5 and 17.5, respectively.
• Reasoning & Logic: In GPQA, Claude scores 0.926 against Gemma’s 0.661. The gap widens significantly in specialized benchmarks like TAU2, where Claude achieves 0.985 compared to Gemma’s 0.318.
• Instruction Following: Claude Fable 5 demonstrates superior adherence to prompts with an IFBench score of 0.634, outperforming Gemma’s 0.451.

Cost and Speed

Gemma 4 12B is entirely free to use, with input and output costs at $0.00/1M tokens. In contrast, Claude Fable 5 is a premium tool, costing $12.50/1M input tokens and $50.00/1M output tokens, resulting in a blended cost of $21.88/1M tokens.

Regarding performance, Claude Fable 5 operates at an output speed of 62.827 tok/s, though it requires a time-to-first-token of 55.198s. Performance metrics for Gemma 4 12B remain unknown.

Best Fit

Gemma 4 12B is best suited for developers or hobbyists looking for a cost-effective, lightweight model for basic tasks. Claude Fable 5 is designed for enterprise users, researchers, and engineers who require high-level reasoning, advanced coding assistance, and reliable performance on complex technical benchmarks.