Gemini 3.8 Flash vs GPT-6 Astra

Where it leads

• Lower input and output prices, $0.75 and $3.75 vs $10 and $50 per 1M tokens
• Higher Arena Text score, 1497 Elo vs 1475 Elo
• Accepts audio and video input
• Cheaper cached input, $0.075 vs $1 per 1M tokens
• Batch pricing, $0.375 input and $1.875 output per 1M tokens

Best for

• High-volume agentic and coding workloads where per-token cost dominates the decision
• Multimodal pipelines that need audio, video and PDF input in one model

Watch out for

• The listed price is promotional and ends 31 December 2026; on 1 January 2027 input and output both double, to $1.50 and $7.50, and cached input goes from $0.075 to $0.15
• Output pricing is billed inclusive of thinking tokens, so reasoning-heavy prompts cost more than the output length suggests
• Google’s published comparisons are against its own previous Flash release and were not independently reproduced here

Where it leads

• Higher GPQA Diamond score, 95.8% vs 95.4%
• Higher FrontierMath Tiers 1-3 (v2) score, 93.7% vs 68.4%
• Higher SimpleQA Verified score, 75.6% vs 69.7%
• Longer responses, up to 128,000 vs 65,536 output tokens

Best for

• Frontier reasoning and agentic evaluations where deep-context retrieval accuracy is the binding constraint
• Workloads that can be kept under the long-context threshold, where the effective rate stays at $10 / $50

Watch out for

• Long-context billing is a cliff, not a taper: a request over the long-context threshold is rebilled in full at $20 per million input and $75 per million output, so a prompt that crosses it costs roughly double
• GPT-6 Astra is the first publicly released model OpenAI classifies as crossing the Critical cybersecurity threshold under its own Preparedness Framework, which carries additional deployment safeguards
• Vendor-reported benchmark figures come from OpenAI’s own launch material and its own harness; they are not independently reproduced here