In recent years, OpenAI has released many advanced AI models, making it harder for developers and businesses to choose the right one. The GPT series and other OpenAI API models continue to improve in performance, but selecting the best model for your needs requires careful consideration.
Common Questions:
- “Which model should I use?”
- “What are the differences in cost and performance?”
- “Which model is best for my use case?”
This article provides an overview of OpenAI’s latest GPT models in 2025, explaining their features, pricing, and best use cases. By the end, you’ll have a clear idea of which model suits your project best.
OpenAI GPT Model Lineup (March 2025)
OpenAI’s models are grouped into the following categories:
| Category | Model Name |
|---|---|
| Flagship Chat Models | GPT-4.5 Preview, GPT-4o, GPT-4o Audio |
| Reasoning Models | o3-mini, o1, o1-mini |
| Cost-Optimized Models | GPT-4o mini, GPT-4o mini Audio |
| Real-Time Models | GPT-4o Realtime, GPT-4o mini Realtime |
| Previous GPT Models | GPT-4 Turbo, GPT-4, GPT-3.5 Turbo |
| Image Generation | DALL-E 3, DALL-E 2 |
| Text Embedding | text-embedding-3-large, text-embedding-3-small, text-embedding-ada-002 |
| Speech & Audio Models | TTS-1, TTS-1 HD, Whisper |
| Moderation Models | omni-moderation, text-moderation |
| Base Models | babbage-002, davinci-002 |
Let’s take a closer look at each category.
Flagship Models
GPT-4.5 Preview
Overview:
This is currently OpenAI’s most powerful and largest GPT model. It has deep knowledge of the world and an excellent ability to understand what users want. It excels at creative tasks and planning complex projects.
Key Features:
- Context Window: 128,000 tokens (enabling it to work with very long documents or multiple documents at once)
- Max Output: 16,384 tokens
- Knowledge Cutoff: October 2023
- Modalities: Supports both text and image inputs/outputs
Pricing:
- Input: $75.00 per million tokens
- Cached Input: $37.50 per million tokens
- Output: $150.00 per million tokens
Speed:
Due to its large size, it is slower than some models – taking about 5 to 10 times longer to generate responses compared to GPT-4o. However, it offers deeper context understanding.
Use Cases:
- Writing long, creative stories
- Assisting with complex report writing
- Multi-step planning
- Tasks requiring expert-level knowledge and creativity
- Summarizing lengthy documents with extensive context
GPT-4o
(“o” stands for “omni”)
Overview:
GPT-4o is a fast, high-performance flagship model capable of handling a wide range of tasks. It supports multi-modal inputs (text + images) and multiple languages, balancing high performance with low cost.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 16,384 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text and image input/output
- Generates over 100 tokens per second (far exceeding the roughly 20 tokens per second of previous models)
Pricing:
- Input: $2.50 per million tokens
- Cached Input: $1.25 per million tokens
- Output: $10.00 per million tokens
Performance:
It matches or exceeds GPT-4 Turbo for English text processing and outperforms it in non-English languages. With high throughput and a fivefold increase in rate limit, it is also great for real-time applications.
Use Cases:
- General chatbots and virtual assistants
- Customer support chat AI
- Coding assistance
- Document summarization and translation
- Creative writing
- Analyzing and describing images
GPT-4o Audio
Overview:
This model is part of the GPT-4o family and is designed for audio. It accepts and produces voice, making it ideal for voice conversations and generating audio content.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 16,384 tokens
- Knowledge Cutoff: October 2023
- Modalities: Supports both text and voice (instead of images)
- Uses WebSocket or WebRTC for streaming voice responses
Pricing:
- Text Input: $2.50 per million tokens
- Text Output: $10.00 per million tokens
- Voice Input: $40.00 per million tokens
- Voice Output: $80.00 per million tokens
Voice Quality:
Designed to add natural human-like nuances in conversation, though voice output is limited to around 4096 tokens (a few minutes of speech).
Use Cases:
- Voice assistants and conversational agents
- Customer support via voice
- Language learning partners
- Virtual receptionists
- Generating high-quality narration for audiobooks or news reading
Reasoning Models (For Problem Solving and Logical Tasks)
o3-mini
Overview:
A small and cost-effective reasoning model that is well-suited for coding, math, and science tasks. It’s an improved version of o1-mini with enhanced performance.
Key Features:
- Context Window: 200,000 tokens
- Max Output: 100,000 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text only
- Supports tool usage and structured outputs
Pricing:
- Input: $1.10 per million tokens
- Cached Input: $0.55 per million tokens
- Output: $4.40 per million tokens
Performance:
Balances fast response with solid reasoning, making it very accurate for coding and math problems.
Use Cases:
- Automated code generation and debugging
- Solving mathematical problems
- Analyzing scientific literature
- Q&A involving equations and structured data
- Generating landing pages and converting text to SQL
- Extracting graph-related data
o1
Overview:
The o1 series is a top-of-the-line reasoning model that excels at solving complex problems using a “think before you answer” approach. It supports tool use, structured outputs, and even image inputs.
Key Features:
- Context Window: 200,000 tokens
- Max Output: 100,000 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text and image input/output
Pricing:
- Input: $15.00 per million tokens
- Cached Input: $7.50 per million tokens
- Output: $60.00 per million tokens
Reasoning Process:
It uses multiple internal reasoning steps before generating a final answer, which can slow down response time but improves logical consistency.
Use Cases:
- Solving math proofs
- Debugging code and explaining it
- Answering complex scientific or technical questions
- Tackling logic puzzles
- Multi-step STEM tasks that require thorough reasoning
o1-mini
Overview:
A faster, more cost-effective version of o1, recommended mainly if high performance isn’t as critical. However, OpenAI suggests using o3-mini for similar tasks as it offers a better balance.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 65,536 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text only
Pricing:
- Input: $1.10 per million tokens
- Cached Input: $0.55 per million tokens
- Output: $4.40 per million tokens
Performance:
While smaller and faster than o1, its reasoning ability is slightly less advanced compared to the latest o3-mini.
Use Cases:
- Generating and analyzing code with long contexts
- Refactoring long functions or multi-file projects
- Tackling advanced math problems where both speed and low cost are important
Cost-Optimized Models
GPT-4o mini
Overview:
A smaller, lighter version of GPT-4o designed to be fast and cost-effective for everyday tasks. It retains the ability to handle a large context (128K tokens) and much of GPT-4o’s knowledge.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 16,384 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text and image input/output
- Extremely fast response times
Pricing:
- Input: $0.15 per million tokens
- Cached Input: $0.075 per million tokens
- Output: $0.60 per million tokens
Performance:
Though it handles large contexts like GPT-4o, its smaller size means it is less capable for very complex reasoning or creative tasks.
Use Cases:
- Chatbots with high API call frequency
- Real-time dynamic text generation (e.g., in video games for NPC dialogue)
- Automated social media post creation
- Text classification and keyword extraction
- Simple translation and tagging tasks
GPT-4o mini Audio
Overview:
This model adds audio input and output to the GPT-4o mini, making it a low-cost option for voice-based applications.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 16,384 tokens
- Knowledge Cutoff: October 2023
- Modalities: Supports text and voice
Pricing:
- Text Input: $0.15 per million tokens
- Text Output: $0.60 per million tokens
- Voice Input: $10.00 per million tokens
- Voice Output: $20.00 per million tokens
Use Cases:
- Voice chat services (for call centers, for example)
- Voice assistants in IoT devices
- Lightweight systems for embedded hardware
- Generating simple narration or in-app voice reading
Real-Time Models
GPT-4o Realtime
Overview:
This version of GPT-4o is optimized for real-time use. It uses WebSocket and streaming APIs to minimize delay, making it perfect for live interactions.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 4,096 tokens
- Knowledge Cutoff: October 2023
- Modalities: Supports text and voice
- Designed to minimize latency
Pricing:
- Text Input: $5.00 per million tokens
- Cached Text Input: $2.50 per million tokens
- Text Output: $20.00 per million tokens
- Voice Input: $40.00 per million tokens
- Cached Voice Input: $2.50 per million tokens
- Voice Output: $80.00 per million tokens
Performance:
Optimized for speed, it can start generating responses even while the user is still speaking, mimicking natural conversation.
Use Cases:
- Interactive voice assistants (like smart speakers or robots)
- Live chat support
- In-game NPC conversations
- Real-time video analysis combined with instant commentary
- Devices for visually impaired users
GPT-4o mini Realtime
Overview:
A real-time tuned version of GPT-4o mini. Its lightweight design ensures ultra-low latency even under heavy loads.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 4,096 tokens
- Knowledge Cutoff: October 2023
- Modalities: Text and voice support
Pricing:
- Text Input: $0.60 per million tokens
- Cached Text Input: $0.30 per million tokens
- Text Output: $2.40 per million tokens
- Voice Input: $10.00 per million tokens
- Cached Voice Input: $0.30 per million tokens
- Voice Output: $20.00 per million tokens
Performance:
Offers extremely fast responses thanks to its simple architecture and real-time API optimization.
Use Cases:
- Real-time chat for large-scale services
- Social media bots interacting with many users simultaneously
- Live stream comment response systems
- Interactive educational tutors that provide instant feedback
- Any scenario where low latency is critical
Legacy GPT Models
GPT-4 Turbo
Overview:
Introduced in November 2023 as an improved version of GPT-4, GPT-4 Turbo supports a 128K context and image inputs, with updated knowledge until early 2023. However, the newer GPT-4o is now recommended.
Key Features:
- Context Window: 128,000 tokens
- Max Output: 4,096 tokens
- Knowledge Cutoff: December 2023
- Modalities: Text and image
Pricing:
- Input: $10.00 per million tokens
- Output: $30.00 per million tokens
Performance:
Faster token processing than GPT-4, with an output speed of about 20 tokens per second. Its knowledge cutoff has been extended from 2021 to April 2023, improving overall problem-solving and coding support.
Use Cases:
- Long conversations (e.g., editing an entire novel)
- Image-based dialogues (such as discussing UI design mockups)
- Analyzing images of charts and graphs for summaries
- Advanced summarization and decision-making support
GPT-4
Overview:
Released in early 2023, GPT-4 is the flagship model that gained huge attention for its high reasoning ability and creativity. It comes in versions with 8K and 32K context sizes.
Key Features:
- Context Window: 8,192 tokens
- Max Output: 8,192 tokens
- Knowledge Cutoff: December 2023
- Modalities: Text only
- Generates about a dozen tokens per second
Pricing:
- Input: $30.00 per million tokens
- Output: $60.00 per million tokens
Performance:
It provides very high reasoning accuracy, though responses are a bit slower. It has been recognized for its creative consistency and even scored as high as top human performers on difficult tests.
Use Cases:
- Legal document analysis
- Summarizing medical research papers
- Programming and coding assistance
- Creative writing
- Serving as the “brain” of AI agents that integrate with external tools
GPT-3.5 Turbo
Overview:
This model was the first version of ChatGPT (GPT-3.5) made available via API. It became widely used from late 2022 through 2023 because of its speed and low cost, setting an industry standard.
Key Features:
- Context Window: 16,385 tokens
- Max Output: 4,096 tokens
- Knowledge Cutoff: September 2021
- Modalities: Text only
- Generates responses very fast (50–70 tokens per second)
Pricing:
- Input: $0.50 per million tokens
- Output: $1.50 per million tokens
Performance:
While not as strong as GPT-4 series for complex reasoning, it handles everyday conversations and simple questions very well. Recent updates also added function calling and system messaging, making it versatile for developers.
Use Cases:
- Automated customer support
- Chatbot interactions in video games
- Drafting written content
- Basic summarization tasks
- Large-scale academic experiments (like summarizing massive text corpora)
Image Generation Models
DALL-E 3
Overview:
DALL-E 3 is OpenAI’s latest image generation model, introduced later in 2023 as part of ChatGPT integration. It interprets prompts very well and generates detailed images.
Key Features:
- Generates an image in just a few seconds
- Works together with ChatGPT, where GPT-4 builds detailed prompts
- Maximum resolution of 1024px
- Shows significantly better composition and detail than DALL-E 2
Pricing:
- 1024×1024: $0.08 per image
- 1024×1792: $0.12 per image
Use Cases:
- Creating illustrations
- Generating ad banners automatically
- Prototyping product designs
- Producing concept art for games and films
- Brainstorming design ideas
DALL-E 2
Overview:
Released in 2022, DALL-E 2 was once the go-to image generator. It can produce art in many styles, though its understanding of complex prompts is limited compared to DALL-E 3. It is still available via API for cost-effective needs.
Key Features:
- Similar image generation times as DALL-E 3
- More limited prompt interpretation, especially for detailed relationships between objects
- Excellent for artistic style transformations and photo-realistic images
- Maximum resolution of 1024px
Pricing:
- 1024×1024: $0.04 per image
- 1024×1792: $0.08 per image
Use Cases:
- Helping creators brainstorm ideas
- Generating illustrations for blog posts
- Exploring various artistic styles
- Editing or expanding existing images
- Experimental image generation at low cost
Voice-Related Models
TTS-1 HD (Text-to-Speech High Definition)
Overview:
TTS-1 HD is a high-quality voice synthesis model that produces very natural and smooth speech. It uses advanced deep learning to mimic human intonation and pauses.
Key Features:
- Slower processing than the standard version (not suited for real-time responses)
- Produces very natural, human-like intonation
- Some users even compare its quality to leading commercial products
- Ideal for long reading sessions without listener fatigue
Pricing:
- $30.00 per million characters
Use Cases:
- Generating narrated videos
- Creating long-form audiobooks
- Producing multilingual audio guides
- High-quality final voice synthesis
TTS-1 (Text-to-Speech)
Overview:
This is OpenAI’s first TTS engine, released in November 2023. It comes with six preset voices and is optimized for fast, real-time responses.
Key Features:
- Low-latency synthesis (converts short texts in less than one second)
- Supports streaming output
- Slightly more robotic than the HD version
- Lightweight enough for edge devices, yet scalable on servers
Pricing:
- $15.00 per million characters
Use Cases:
- Voice responses for chat systems
- In-car navigation or smart speakers
- Assistive technologies for the visually impaired
- Educational apps providing quick word pronunciations
- Any scenario where speed is critical
Whisper (Speech-to-Text)
Overview:
Whisper is OpenAI’s speech recognition model, first released as open source in 2022 and later available via API in March 2023. It offers near-human accuracy and supports over 99 languages.
Key Features:
- Supports more than 99 languages including Japanese
- Automatically detects the speaker’s language
- Can provide transcriptions in the same language or translated into English
- Very high accuracy, close to human error rates
Pricing:
- $0.006 per minute for transcription
Use Cases:
- Transcribing meetings or lectures
- Auto-generating subtitles
- Recognizing voice commands in digital assistants
- Transcribing international conferences
- Powering voice input features in ChatGPT
Embedding Models (For Text Similarity and Search)
text-embedding-3-large
Overview:
This is OpenAI’s third-generation, large-scale text embedding model. It converts text into high-dimensional vectors (3072 dimensions) for semantic similarity and search tasks. It’s the successor to embedding-ada-002.
Key Features:
- Generates 3072-dimensional vectors
- Captures subtle differences in meaning
- Improved multilingual search scores
- Better performance on English tasks
Pricing:
- $0.13 per million tokens
Use Cases:
- Building large vector databases
- Internal document search systems
- Retrieval-Augmented Generation (RAG)
- Recommendation systems based on text similarity
- Cluster analysis for similar content
text-embedding-3-small
Overview:
A smaller, faster version of the third-generation embedding model. It produces 1536-dimensional vectors, offering a great balance between speed and performance.
Key Features:
- Uses 1536 dimensions (same as ada-002 but with improved accuracy)
- Better multilingual search performance
- Faster vectorization suitable for large-scale processing
Pricing:
- $0.02 per million tokens
Use Cases:
- Mobile app integration for text embedding
- Batch processing large volumes of data (like millions of product reviews)
- Search systems that mix Japanese and English content
- Optimizing knowledge search in ChatGPT’s API
text-embedding-ada-002
Overview:
Released in December 2022, this was the standard embedding model for a long time. It generates 1536-dimensional vectors.
Key Features:
- Produces 1536-dimensional vectors
- Reliable for basic semantic similarity tasks
- Uses fixed training data until 2022
Pricing:
- $0.10 per million tokens
Use Cases:
- Document search services (like those used in NotionAI or Obsidian plugins)
- Matching FAQs for customer support
- Text classification by comparing representative embeddings
- Maintaining compatibility in existing systems
Moderation Models
omni-moderation
Overview:
Introduced in September 2024, omni-moderation is a multi-modal and multilingual content moderation model based on GPT-4o. It accurately detects harmful text and images.
Key Features:
- Supports both text and image moderation
- Much improved accuracy over the previous text-moderation model
- Reduces misclassifications in non-English content
- Outputs scores for various categories like hate, violence, sexual content, and self-harm
- Provided free of charge for API users
Use Cases:
- Ensuring safety in backend systems for online services
- Moderating user-generated content on platforms and chatbots
- Real-time content monitoring
- Safety checks in AI-generated responses
- Detecting harmful content in images
text-moderation
Overview:
An older moderation model that handles text only. Today, omni-moderation is recommended over this version.
Model Selection Guide: Recommended Models by Use Case
📌 Cost-Efficient Chatbots
- Recommended: GPT-4o mini
- Alternative: GPT-3.5 Turbo
- Reason: GPT-4o mini is low-cost, supports multi-modal inputs, and outperforms GPT-3.5 Turbo.
📌 Advanced Reasoning and Analysis
- Recommended: o3-mini
- Alternative: o1 (for even more complex tasks)
- Reason: o3-mini is optimized for complex reasoning and is very cost-effective.
📌 Creative Writing
- Recommended: GPT-4o
- Alternative: GPT-4.5 Preview (if budget allows)
- Reason: GPT-4o excels in creative content, while GPT-4.5 Preview offers even more creativity at a higher cost.
📌 Image Generation
- Recommended: DALL-E 3
- Alternative: DALL-E 2 (if cost is a concern)
- Reason: DALL-E 3 provides the latest in image generation, whereas DALL-E 2 is more budget-friendly but with slightly lower quality.
📌 Voice Interfaces
- Recommended: GPT-4o mini Audio
- Alternative: GPT-4o Audio (for higher quality)
- Reason: GPT-4o mini Audio offers affordable voice features, with GPT-4o Audio providing better quality if needed.
📌 Real-Time Responses
- Recommended: GPT-4o mini Realtime
- Alternative: GPT-4o Realtime (if quality is more important)
- Reason: GPT-4o mini Realtime delivers low-latency responses, while GPT-4o Realtime is higher quality but more expensive.
📌 Text Embedding (Search/Similarity)
- Recommended: text-embedding-3-small
- Alternative: text-embedding-3-large (for higher accuracy)
- Reason: text-embedding-3-small is very efficient, with text-embedding-3-large offering improved precision when needed.
Pricing Comparison Table
Below is a summary of the pricing for the major OpenAI models (prices are per million tokens in USD):
| Model | Input | Cached Input | Output |
|---|---|---|---|
| GPT-4.5 Preview | $75.00 | $37.50 | $150.00 |
| GPT-4o | $2.50 | $1.25 | $10.00 |
| GPT-4o Audio | $2.50 | – | $10.00 |
| o3-mini | $1.10 | $0.55 | $4.40 |
| o1 | $15.00 | $7.50 | $60.00 |
| o1-mini | $1.10 | $0.55 | $4.40 |
| GPT-4o mini | $0.15 | $0.075 | $0.60 |
| GPT-4o mini Audio | $0.15 | – | $0.60 |
| GPT-4o Realtime | $5.00 | $2.50 | $20.00 |
| GPT-4o mini Realtime | $0.60 | $0.30 | $2.40 |
| GPT-4 Turbo | $10.00 | – | $30.00 |
| GPT-4 | $30.00 | – | $60.00 |
| GPT-3.5 Turbo | $0.50 | – | $1.50 |
Note: Cached input refers to reusing previously processed input tokens, which reduces cost when using the same context repeatedly.
Frequently Asked Questions about ChatGPT API
For more detailed information, please visit the official website
https://platform.openai.com/docs/models.
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