GPT-4o
o200k_base
Structural tokenization analysis engine. Optimized for GPT-4o inputs. Calibrate context windows and compute precise API economics in real-time.
Context
128k
Type
LLM
Encoding
o 200k base
CH44
WORD9
ENCODINGo200k_base
// HAPPYTOKENIZER: WAITING FOR INPUT STREAM
Quick Answers
What is the GPT-4o token limit?
GPT-4o supports a 128,000 token context window. Paste your text above to see how much of that window your prompt fills.
What tokenizer does GPT-4o use?
GPT-4o uses OpenAI's o200k_base encoding. This page counts tokens with the vendor's real vocabulary, so the numbers match what the API sees.
How much does GPT-4o cost per million tokens?
GPT-4o costs $2.50 per million input tokens and $10.00 per million output tokens, with cached input at $1.25 per million.
Model Insights
Modalities
InTextImage
OutText
Supported Features
StreamingStructured OutputsFunction CallingWeb SearchPrompt CachingReasoning Tokens
Supported Endpoints
ResponsesBatch
Cost Manifest
Input / 1M$2.50
Output / 1M$10.00
Cached Write$1.25
* Rates are estimated based on OpenAI standard tier. Actual billing may vary based on batch processing and enterprise agreements.
// Technical Specifications
- ARCHITECTURE ID
- gpt-4o
- TOKEN ENCODING
- o200k_base
- MAX CONTEXT
- 128,000TOKENS