Head-to-head · 2026
Gemini 3.5 Flash vs GPT-5.2 Pro
Verdict. Flash for cost-efficient agentic coding at scale; GPT-5.2 Pro for voice-native and broad multimodal apps. Note: GPT-5.2 Pro is superseded by GPT-5.5 — see Grok 4.3 vs GPT-5.5 or Opus 4.8 vs GPT-5.5 for the April–May 2026 matchups.
| Gemini 3.5 Flash | GPT-5.2 Pro | |
|---|---|---|
| Provider | Google DeepMind | OpenAI |
| Released | 2026-05-19 | 2026-01-01 |
| Context | 1M | 196K |
| Max output | 64K | — |
| Input /1M | $1.50 | $21.00 |
| Output /1M | $9.00 | $168.00 |
| Modalities | text, vision, audio, video | text, vision, audio |
The analysis
Gemini 3.5 Flash is built for the agent runtime: 76.2% Terminal-Bench 2.1, 83.6% MCP Atlas, 1M context, at sub-flagship pricing. If your bottleneck is running many agent steps affordably, Flash is hard to beat.
GPT-5.2 Pro was the generalist with native voice and the deepest integration ecosystem — the better default for consumer-facing multimodal and voice products, less optimal as a high-volume coding-agent runtime on cost grounds.
Currency note: GPT-5.2 Pro has since been superseded by GPT-5.5 (April 2026), which extended the lead on computer-use and knowledge work at the time. OpenAI has released newer models since (GPT-6.1 Sol on 29 September 2026); re-check the Flash-as-runtime logic against the OpenAI model you deploy.
Pick Gemini 3.5 Flash if…
- Cost-sensitive, high-volume agentic coding
- MCP-heavy tool pipelines
- Long-context at low cost
Pick GPT-5.2 Pro if…
- Voice is central to the product
- Broadest multimodal coverage needed
- Deep OpenAI ecosystem lock-in
Gemini 3.5 Flash
Frontier agentic coding at sub-flagship economics.
GPT-5.2 Pro
Previous OpenAI flagship — superseded by GPT-5.5.