GPT-3.5 Turbo vs Gemini 2.5 Flash
Compare pricing, context windows, and strengths for GPT-3.5 Turbo by OpenAI and Gemini 2.5 Flash by Google - and see how to put either to work in Appaca.
GPT-3.5 Turbo
Legacy lightweight GPT model for cheap text generation and chat tasks; now replaced by faster, smarter, and cheaper 4o-mini models.
View GPT-3.5 TurboGemini 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-3.5 Turbo vs Gemini 2.5 Flash at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-3.5 Turbo | Gemini 2.5 Flash |
|---|---|---|
| Provider | OpenAI | |
| Model type | Text | Text |
| Context window | 16.4K tokens | 1M tokens |
| Input price | $0.5 / 1M tokens | $0.3 / 1M tokens |
| Output price | $1.5 / 1M tokens | $2.5 / 1M tokens |
| Status | Current | Current |
How GPT-3.5 Turbo and Gemini 2.5 Flash differ
What the numbers mean in practice when choosing between GPT-3.5 Turbo and Gemini 2.5 Flash.
-
Gemini 2.5 Flash is 40% cheaper on input tokens ($0.3 vs $0.5 per million), which adds up quickly in document-heavy workloads.
-
GPT-3.5 Turbo is 40% cheaper on output tokens ($1.5 vs $2.5 per million) - the bigger factor for tools that generate long documents.
-
Gemini 2.5 Flash's 1M tokens context window is roughly 61.0x larger than GPT-3.5 Turbo's 16.4K tokens, so it can work across bigger codebases, contracts, or archives in one pass.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-3.5 Turbo
1. Extremely low-cost text model
- One of the cheapest legacy models available.
- Suitable for very high-volume workloads with simple requirements.
2. Good for lightweight NLP tasks
- Classification, summarization, rewriting, paraphrasing, intent detection.
- Works for simple logic tasks and short reasoning sequences.
3. Works well for basic chatbots
- Optimized for Chat Completions API, originally powering early ChatGPT use cases.
- Good for rule-based or templated conversation flows.
4. Stable and predictable outputs
- Legacy behavior makes it suitable for systems built years ago that rely on its quirks.
- Good for backward compatibility or long-term enterprise pipelines.
5. Supports fine-tuning
- Useful for teams maintaining older fine-tuned GPT-3.5 models.
- Allows domain-specific compression of older datasets.
6. Limited capabilities compared to newer models
- No vision, no audio, no streaming, and no function calling.
- Much weaker reasoning and correctness vs GPT-4o mini or GPT-5.1.
7. Small context window (16K)
- Limited for multi-document tasks or long conversations.
- Best used for short, simple prompts or structured tasks.
8. Recommended migration path
- OpenAI explicitly recommends using GPT-4o mini instead.
- 4o mini is cheaper, smarter, faster, multimodal, and far more capable.
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-3.5 Turbo or Gemini 2.5 Flash - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-3.5 Turbo 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-3.5 Turbo or Gemini 2.5 Flash. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-3.5 Turbo, 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-3.5 Turbo or Gemini 2.5 Flash - connected to the tools you already use.
Related comparisons
See how GPT-3.5 Turbo and Gemini 2.5 Flash stack up against other models in the directory.
FAQs
GPT-3.5 Turbo is generally cheaper: $0.5 input / $1.5 output per million tokens, versus $0.3 / $2.5 for Gemini 2.5 Flash. Actual cost depends on how many tokens your workload reads and writes.
Gemini 2.5 Flash has the larger context window at 1M tokens, compared to 16.4K tokens for GPT-3.5 Turbo. A larger window means the model can consider more text at once - useful for long contracts, codebases, or months of records.
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-3.5 Turbo, 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-3.5 Turbo, 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-3.5 Turbo 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.