GPT-3.5 Models by OpenAI
Last refreshed 2026-06-01. Next refresh: weekly.
Details
Capabilities
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WebsiteAbout
The gpt-35-turbo (also known as ChatGPT) is the most capable and cost-effective model in the GPT-3.5 family which has been optimized for chat using the Chat Completions API. It is a language model designed for conversational interfaces and the model behaves differently than previous GPT-3 models. Previous models were text-in and text-out, meaning they accepted a prompt string and returned a completion to append to the prompt. However, the ChatGPT model is conversation-in and message-out. The model expects a prompt string formatted in a specific chat-like transcript format and returns a completion that represents a model-written message in the chat.
Decision facts
- Best fit
- structured outputscoding
- Capability starting point
- GPT-3.5 Turbo 16k with 16k context and structured outputs
- Lowest tracked input
- GPT-3.5 Turbo · $0.500/1M · Azure OpenAI
- Closest related family
- GPT-5
Current Variants
Use-when guidance is based on each model's tracked capabilities, context window, release date, and replacement status.
Use when the workload needs 4k context, 20B parameters, and structured outputs.
Use when the workload needs 16k context, 20B parameters, and structured outputs.
| Model | Use when | Released | Signals | Status |
|---|---|---|---|---|
| GPT-3.5 Turbo (Instruct) | Use when the workload needs 4k context, 20B parameters, and structured outputs. | 2023-09 | 4k context20B parametersstructured outputs | Current |
| GPT-3.5 Turbo 16k | Use when the workload needs 16k context, 20B parameters, and structured outputs. | 2023-06 | 16k context20B parametersstructured outputs | Current |
Release Timeline
3 release groupsReplaced By
Keep for legacy integrations; evaluate GPT-4.1 Mini before new work.
Specifications(3 models)
| Model | Released | Context | Parameters | Structured Outputs |
|---|---|---|---|---|
| GPT-3.5 Turbo (Instruct) | 2023-09 | 4k | 20B | Yes |
| GPT-3.5 Turbo 16k | 2023-06 | 16k | 20B | Yes |
Available From(6 providers)
Pricing
| Model | Provider | Input / 1M | Output / 1M | Type |
|---|---|---|---|---|
| GPT-3.5 Turbo 16k | Azure OpenAI | $0.5 | $2 | Serverless |
| GPT-3.5 Turbo (Instruct) | Azure OpenAI | $1.5 | $2 | Serverless |
| GPT-3.5 Turbo (Instruct) | OpenAI API | $1.5 | $2 | Serverless |
| GPT-3.5 Turbo (Instruct) | OpenRouter | $1.5 | $2 | Serverless |
| GPT-3.5 Turbo (Instruct) | Vercel AI Gateway | $1.5 | $2 | Serverless |
| GPT-3.5 Turbo 16k | OpenRouter | $3 | $4 | Serverless |
