Gemini 3.1 Pro Preview vs o4 Mini

Summary of head-to-head results from our 12-test suite: Gemini wins on constrained_rewriting (4 vs 3), creative_problem_solving (5 vs 4), agentic_planning (5 vs 4) and safety_calibration (2 vs 1). o4 Mini wins on tool_calling (5 vs 4) and classification (4 vs 2). The remaining tests tie: structured_output (both 5), strategic_analysis (both 5), faithfulness (both 5), long_context (both 5), persona_consistency (both 5) and multilingual (both 5). Context and ranks: Gemini’s 5s place it tied for 1st in structured_output, strategic_analysis, faithfulness, long_context, persona_consistency and multilingual (many models share top scores), and Gemini ranks 2nd of 23 on AIME 2025 in our tests (AIME 2025 95.6). o4 Mini is tied for 1st on tool_calling (rank 1 of 54, tied with 16) and ranks 1st on classification (tied); its external MATH Level 5 score is 97.8% (rank 2 of 14, Epoch AI). What this means for tasks: • Tool-heavy developer flows and function selection: o4 Mini’s 5/5 tool_calling and top rank indicate more reliable function selection and argument sequencing in our tests. • Agentic planning, complex decomposition, and creative brainstorming: Gemini’s 5/5 agentic_planning and 5/5 creative_problem_solving (both top ranks) yield clearer, higher-quality decompositions and novel feasible ideas in our tests. • Constrained outputs (hard character limits): Gemini’s 4 vs o4’s 3 (Gemini rank 6 vs o4 rank 31) shows Gemini handled strict compression and formatting better in our runs. • Safety and refusal calibration: Gemini scored 2 vs o4’s 1; Gemini ranks 12 of 55 vs o4 32 of 55, so Gemini is more calibrated on borderline requests in our testing. External benchmarks (Epoch AI): o4 Mini scores 97.8% on MATH Level 5 (Epoch AI); Gemini scores 95.6% on AIME 2025 (Epoch AI). These external results are supplementary evidence and reflect narrower math contest measures.

Prices in the payload are per mTok: Gemini input $2 and output $12; o4 Mini input $1.1 and output $4.4. Output costs dominate: per 1M output tokens Gemini costs $12,000 vs o4 Mini $4,400 (difference $7,600). Including input tokens at parity (50% input / 50% output) yields ~ $14,000/1M for Gemini vs $5,500/1M for o4 Mini. At scale the gap widens linearly: for 10M output tokens Gemini $120,000 vs o4 $44,000 (diff $76,000); for 100M output tokens Gemini $1,200,000 vs o4 $440,000 (diff $760,000). Cost-sensitive startups, high-volume APIs, and consumer-facing apps should care about the gap; research teams or products that need Gemini’s edge in agentic planning, creative problem solving, constrained rewriting, or very large context may accept the higher cost.

Choose Gemini 3.1 Pro Preview if you need best-in-class agentic planning, creative problem solving, constrained rewriting, safety calibration, or extreme long-context handling (Gemini context window 1,048,576 tokens). Choose o4 Mini if you need cost-efficient production throughput, top-ranked tool calling and classification, strong MATH Level 5 performance, and a smaller context window (200,000 tokens) at ~2.73× lower output cost. If budget is tight at high volumes (10M+ output tokens/month), prefer o4 Mini; if quality on the specific wins above matters and budget allows, prefer Gemini.