Gemini 2.5 Flash vs GPT-5.6
Pricing, benchmarks, and use case comparison
Quick take
- •Gemini 2.5 Flash is meaningfully stronger at cost efficiency (92 vs 70 on our capability index).
- •GPT-5.6 is meaningfully stronger at coding (94 vs 75).
- •Gemini 2.5 Flash is 94% cheaper on input tokens, which compounds fast on high-volume or agentic workloads.
Specs comparison
| Gemini 2.5 Flash | GPT-5.6 | |
|---|---|---|
| Provider | Google DeepMind | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓1,048,576 tokens (1M) input; up to 65,535 output | Not announced |
| Input / 1M tokens | ✓$0.30 | 5 |
| Output / 1M tokens | $2.50 | 30 |
| Release date | 2025-06 | 2026-06 |
Benchmarks
| Benchmark | Gemini 2.5 Flash | GPT-5.6 |
|---|---|---|
| Context window | 1M tokens | - |
| Input price | $0.30/1M | - |
| Terminal-Bench 2.1 (Sol) | - | 88.8% |
| Terminal-Bench 2.1 (Terra) | - | 82.5% |
| Terminal-Bench 2.1 (Luna) | - | 84.3% |
| Terminal-Bench 2.1 | - | 88.8 |
| ExploitBench | - | Competitive with Anthropic Mythos Preview |
| ExploitGym | - | Significant improvements |
| GeneBench v1 | - | Not announced |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose Gemini 2.5 Flash if...
- →High-volume, latency-sensitive production workloads
- →Chatbots, extraction, classification, and summarization at scale
- →You need decent reasoning but must control costs
Choose GPT-5.6 if...
- →You want to standardize on one model generation but route requests across cost/quality tiers
- →You are an approved preview partner exploring the newest OpenAI capabilities
- →Workloads spanning agentic coding, knowledge work, and research where tier flexibility helps