Gemma 4 31B vs Grok 4

Across our 12-test suite, Gemma 4 31B wins 4 benchmarks outright, ties 7, and loses 1. Grok 4 wins 1, ties 7, and loses 4. Here is the test-by-test breakdown:

Where Gemma 4 31B wins:

• Tool calling (5 vs 4): Gemma 4 31B ranks tied for 1st among 54 models in our testing. Grok 4 ranks 18th. This covers function selection, argument accuracy, and sequencing — directly relevant to agentic and API-driven workflows. A one-point gap here is meaningful.
• Agentic planning (5 vs 3): Gemma 4 31B ranks tied for 1st among 54 models; Grok 4 ranks 42nd out of 54. Goal decomposition and failure recovery are where Grok 4 struggles most relative to the field. This is a significant gap for anyone building multi-step AI agents.
• Structured output (5 vs 4): Gemma 4 31B ranks tied for 1st among 54 models; Grok 4 ranks 26th. JSON schema compliance and format adherence matters for any pipeline that parses model output programmatically.
• Creative problem solving (4 vs 3): Gemma 4 31B ranks 9th of 54 models; Grok 4 ranks 30th. Non-obvious, feasible ideation is an area where Gemma 4 31B meaningfully outpaces Grok 4 in our tests.

Where Grok 4 wins:

• Long context (5 vs 4): Grok 4 scores 5/5 (tied for 1st among 55 models) vs Gemma 4 31B's 4/5 (ranked 38th of 55). Retrieval accuracy at 30K+ tokens is the one area where Grok 4 has a clear edge. Both models offer similar context window sizes (256K for Grok 4, 262K for Gemma 4 31B), but Grok 4's retrieval performance at depth is stronger in our testing.

Ties (7 benchmarks): Strategic analysis, constrained rewriting, faithfulness, classification, safety calibration, persona consistency, and multilingual all end in ties — with both models typically sharing scores with a large pool of other models. Strategic analysis (both 5/5) and faithfulness (both 5/5) represent genuine parity at the top of the field. Safety calibration (both 2/5) is a shared weakness — both rank around 12th of 55 models, below the median, meaning both refuse too little or too much relative to our test suite's ideal calibration.

Context: Neither model has published external benchmark scores (SWE-bench Verified, AIME 2025, MATH Level 5) in the payload, so we cannot supplement our internal scores with third-party data for this comparison.

The price gap here is not a rounding error — it is a 39x difference on output tokens. Gemma 4 31B costs $0.13/M input and $0.38/M output. Grok 4 costs $3.00/M input and $15.00/M output.

At 1M output tokens/month: Gemma 4 31B costs $0.38; Grok 4 costs $15.00. At 10M output tokens/month: Gemma 4 31B costs $3.80; Grok 4 costs $150.00. At 100M output tokens/month: Gemma 4 31B costs $38; Grok 4 costs $1,500.

One additional consideration: Grok 4 uses reasoning tokens (noted in the payload), and those tokens count toward your bill. In practice, complex queries will trigger extended reasoning chains, pushing real costs well above the stated $15/M rate. Teams building agentic pipelines or high-volume APIs should treat Grok 4's pricing as a floor, not a ceiling.

Who should care? Any developer or business running more than minimal query volumes. At 10M tokens/month, Grok 4 costs ~$146 more per month for output alone — and Gemma 4 31B scores higher on tool calling and agentic planning, the two benchmarks most relevant to high-volume API usage.

Choose Gemma 4 31B if:

• You are building agentic workflows or tool-calling pipelines (scores 5 vs Grok 4's 3 on agentic planning, 5 vs 4 on tool calling in our tests)
• You need structured JSON output reliability for downstream parsing (5 vs 4)
• Cost is a factor at any meaningful scale — $0.38/M output vs $15/M is a 39x difference that compounds fast
• You want multimodal input (text, image, video) — Gemma 4 31B supports video input per the payload; Grok 4 supports text, image, and file
• You want reasoning/thinking mode without it being opaque — Gemma 4 31B supports include_reasoning and reasoning parameters

Choose Grok 4 if:

• Your primary use case is long-document retrieval or summarization at depth (scores 5/5 vs Gemma 4 31B's 4/5 in our tests, ranked 1st of 55 models)
• You are working with file inputs specifically (Grok 4 supports file modality per the payload)
• You need parallel tool calling and logprobs support (both present in Grok 4's parameter list in the payload)
• Budget is not a constraint and you want Grok 4's long-context retrieval ceiling

The default recommendation is Gemma 4 31B. It wins more benchmarks, costs dramatically less, and Grok 4's single advantage — long context retrieval — only justifies the 39x output cost premium for a narrow set of document-heavy use cases.