O3 Pro
o200k_base
Structural tokenization analysis engine. Optimized for O3 Pro inputs. Calibrate context windows and compute precise API economics in real-time.
Context
200k
Type
LLM
Encoding
o 200k base
CH44
WORD9
ENCODINGo200k_base
// HAPPYTOKENIZER: WAITING FOR INPUT STREAM
Quick Answers
What is the O3 Pro token limit?
O3 Pro supports a 200,000 token context window. Paste your text above to see how much of that window your prompt fills.
What tokenizer does O3 Pro use?
O3 Pro 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 O3 Pro cost per million tokens?
O3 Pro costs $20.00 per million input tokens and $80.00 per million output tokens, with cached input at $0.00 per million.
Model Insights
Modalities
InTextImage
OutText
Supported Features
StreamingStructured OutputsFunction CallingWeb SearchPrompt CachingReasoning Tokens
Supported Endpoints
ResponsesBatch
Cost Manifest
Input / 1M$20.00
Output / 1M$80.00
Cached Write$0.00
* Rates are estimated based on OpenAI standard tier. Actual billing may vary based on batch processing and enterprise agreements.
// Technical Specifications
- ARCHITECTURE ID
- o3-pro
- TOKEN ENCODING
- o200k_base
- MAX CONTEXT
- 200,000TOKENS