Gemini 3.1 Flash Lite Preview vs GPT-5.2

Summary of our 12-test suite in our testing: GPT-5.2 wins 4 tests; Gemini wins 1; 7 are ties. Details:

• GPT-5.2 wins (our scores): creative_problem_solving 5 vs 4, classification 4 vs 3, long_context 5 vs 4, agentic_planning 5 vs 4. For developers, those 5-vs-4 wins indicate measurably stronger performance on non-obvious idea generation, accurate routing/classification, retrieval and reasoning across very large contexts, and goal decomposition/recovery. GPT-5.2 ranks tied for 1st on long_context, classification, agentic_planning, and creative_problem_solving in our rankings (e.g., long_context: "tied for 1st with 36 other models").
• Gemini 3.1 Flash Lite Preview wins structured_output: 5 vs 4. That means Gemini is more reliable at JSON/schema compliance and strict format adherence in our tests (Gemini’s structured_output ranks tied for 1st among models).
• Ties (equal scores in our tests): strategic_analysis 5, constrained_rewriting 4, tool_calling 4, faithfulness 5, safety_calibration 5, persona_consistency 5, multilingual 5 — both models perform equivalently on these tasks in our suite. Notably both tie for top safety_calibration and faithfulness.
• External benchmarks (Epoch AI): GPT-5.2 scores 73.8% on SWE-bench Verified (Epoch AI) and ranks 5 of 12, and scores 96.1% on AIME 2025 (Epoch AI), ranking 1 of 23. We cite Epoch AI for those external results.
• Context & features: Gemini has a 1,048,576 token context_window vs GPT-5.2’s 400,000, and Gemini’s modality list includes text+image+file+audio+video->text while GPT-5.2 lists text+image+file->text. Despite Gemini’s larger raw context window, GPT-5.2 still outscored Gemini on our long_context benchmark, which evaluates retrieval accuracy at 30K+ tokens.

Prices from the payload: Gemini 3.1 Flash Lite Preview charges $0.25 per mTok input and $1.50 per mTok output; GPT-5.2 charges $1.75 per mTok input and $14.00 per mTok output. Interpreting mTok as 1k-token billing units, per-1M-token costs are: Gemini input $250, output $1,500; GPT-5.2 input $1,750, output $14,000. Under a realistic 20% input / 80% output token split, monthly totals are:

• 1M tokens/month (200k in / 800k out): Gemini ≈ $1,250 vs GPT-5.2 ≈ $11,550.
• 10M tokens/month (2M in / 8M out): Gemini ≈ $12,500 vs GPT-5.2 ≈ $115,500.
• 100M tokens/month (20M in / 80M out): Gemini ≈ $125,000 vs GPT-5.2 ≈ $1,155,000. Who should care: high-volume deployments (SaaS companies, large-scale agents, startups planning >10M tokens/month) will see six- to ten-fold monthly savings with Gemini. Teams prioritizing task-leading accuracy for agentic planning, long-context reasoning, or competitive math/coding benchmarks may accept GPT-5.2’s substantially higher cost for those gains.

Choose Gemini 3.1 Flash Lite Preview if: you must minimize per-token cost at scale (Gemini output $1.50 vs GPT-5.2 $14.00 per mTok), need multimodal ingestion including audio/video->text, or require maximal advertised context window (1,048,576 tokens). It also wins structured-output tasks (JSON/schema). Choose GPT-5.2 if: you need the best performance on agentic planning, long-context retrieval, classification, or creative problem solving in our tests, and you value the external benchmark wins (AIME 2025 96.1% and SWE-bench Verified 73.8% by Epoch AI) enough to absorb a much higher token bill.