GPT-5.5 vs Gemini 2.5 Flash
Compare pricing, context windows, and strengths for GPT-5.5 by OpenAI and Gemini 2.5 Flash by Google - and see how to put either to work in Appaca.
GPT-5.5
OpenAI's smartest and most capable model yet for agentic coding, knowledge work, and computer use, delivering a new class of intelligence at GPT-5.4 latency.
View GPT-5.5Gemini 2.5 Flash
A fast, cost-efficient multimodal model optimized for everyday tasks with strong speed, long context, and native audio capabilities.
View Gemini 2.5 FlashGPT-5.5 vs Gemini 2.5 Flash at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-5.5 | Gemini 2.5 Flash |
|---|---|---|
| Provider | OpenAI | |
| Model type | Text | Text |
| Context window | 1M tokens | 1M tokens |
| Input price | $5 / 1M tokens | $0.3 / 1M tokens |
| Output price | $30 / 1M tokens | $2.5 / 1M tokens |
| Status | Current | Current |
How GPT-5.5 and Gemini 2.5 Flash differ
What the numbers mean in practice when choosing between GPT-5.5 and Gemini 2.5 Flash.
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Gemini 2.5 Flash is 94% cheaper on input tokens ($0.3 vs $5 per million), which adds up quickly in document-heavy workloads.
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Gemini 2.5 Flash is 92% cheaper on output tokens ($2.5 vs $30 per million) - the bigger factor for tools that generate long documents.
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Both models offer the same 1M tokens context window.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-5.5
1. Strongest Agentic Coding Model
- State-of-the-art on Terminal-Bench 2.0 (82.7%), Expert-SWE (73.1%), and SWE-Bench Pro (58.6%), outperforming GPT-5.4 on complex coding tasks.
- Holds context across large systems, reasons through ambiguous failures, and carries changes through surrounding codebases with fewer tokens.
2. Higher Intelligence at GPT-5.4 Latency
- Co-designed, trained, and served on NVIDIA GB200/GB300 NVL72 systems to match GPT-5.4 per-token latency while performing at a significantly higher level.
- Uses fewer tokens to complete the same tasks, making it more efficient as well as more capable.
3. Powerful for Knowledge Work & Computer Use
- Scores 84.9% on GDPval (44 occupations) and 78.7% on OSWorld-Verified for autonomous computer operation.
- Excels at generating documents, spreadsheets, and reports; naturally moves across finding information, using tools, and checking output.
4. Scientific Research Co-Scientist
- Leading performance on GeneBench, BixBench, and FrontierMath; helped discover a new proof about Ramsey numbers verified in Lean.
- Strong enough to meaningfully accelerate progress at the frontiers of biomedical and mathematical research.
Gemini 2.5 Flash
1. Highly cost-efficient for large-scale workloads
- Extremely low input cost ($0.30/M) and affordable output cost.
- Built for production environments where throughput and budget matter.
- Significantly cheaper than competitors like o4-mini, Claude Sonnet, and Grok on text workloads.
2. Fast performance optimized for everyday tasks
- Ideal for summarization, chat, extraction, classification, captioning, and lightweight reasoning.
- Designed as a high-speed “workhorse model” for apps that require low latency.
3. Built-in “thinking budget” control
- Adjustable reasoning depth lets developers trade off latency vs. accuracy.
- Enables dynamic cost management for large agent systems.
4. Native multimodality across all major formats
- Inputs: text, images, video, audio, PDFs.
- Outputs: text + native audio synthesis (24 languages with the same voice).
- Great for conversational agents, voice interfaces, multimodal analysis, and captioning.
5. Industry-leading long context window
- 1,000,000 token context window.
- Supports long documents, multi-file processing, large datasets, and long multimedia sequences.
- Stronger MRCR long-context performance vs previous Flash models.
6. Native audio generation and multilingual conversation
- High-quality, expressive audio output with natural prosody.
- Style control for tones, accents, and emotional delivery.
- Noise-aware speech understanding for real-world conditions.
7. Strong benchmark performance for its cost
- 11% on Humanity's Last Exam (no tools) - competitive with Grok and Claude.
- 82.8% on GPQA diamond (science reasoning).
- 72.0% on AIME 2025 single-attempt math.
- Excellent multimodal reasoning (79.7% on MMMU).
- Leading long-context performance in its price tier.
8. Capable coding assistance
- 63.9% on LiveCodeBench (single attempt).
- 61.9%/56.7% on Aider Polyglot (whole/diff).
- Agentic coding support + tool use + function calling.
9. Fully supports tool integration
- Function calling.
- Structured outputs.
- Search-as-a-tool.
- Code execution (via Google Antigravity / Gemini API environments).
10. Production-ready availability
- Available in: Gemini App, Google AI Studio, Gemini API, Vertex AI, Live API.
- General availability (GA) with stable endpoints and documentation.
Use GPT-5.5 or Gemini 2.5 Flash - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-5.5 or Gemini 2.5 Flash - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need and it builds a working app powered by GPT-5.5 or Gemini 2.5 Flash. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-5.5, test the same tool on Gemini 2.5 Flash, and keep whichever performs better - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs and it builds a working app powered by GPT-5.5 or Gemini 2.5 Flash - connected to the tools you already use.
Related comparisons
See how GPT-5.5 and Gemini 2.5 Flash stack up against other models in the directory.
FAQs
Gemini 2.5 Flash is generally cheaper: $0.3 input / $2.5 output per million tokens, versus $5 / $30 for GPT-5.5. Actual cost depends on how many tokens your workload reads and writes.
They are equal: both GPT-5.5 and Gemini 2.5 Flash support a 1M tokens context window.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on GPT-5.5, test the same tool on Gemini 2.5 Flash, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by GPT-5.5, Gemini 2.5 Flash, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build AI tools with GPT-5.5 or Gemini 2.5 Flash
Describe the tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.