Claude Sonnet 4.5 vs Gemma 4 31B

Pick Gemma 4 31B if you want the stronger benchmark profile. Claude Sonnet 4.5 only becomes the better choice if multimodal & grounded is the priority or you would rather avoid the extra latency and token burn of a reasoning model.

Gemma 4 31B is clearly ahead on the aggregate, 73 to 68. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Gemma 4 31B's sharpest advantage is in coding, where it averages 80 against 60.8. The single biggest benchmark swing on the page is LiveCodeBench, 53% to 80%. Claude Sonnet 4.5 does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Gemma 4 31B. That is roughly Infinityx on output cost alone. Gemma 4 31B is the reasoning model in the pair, while Claude Sonnet 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Gemma 4 31B gives you the larger context window at 256K, compared with 200K for Claude Sonnet 4.5.