A rate per million tokens is not a budget. The calculator takes your request volume, prompt size and cache hit rate and gives you a monthly figure.
o3 API pricing (October 2026)
OpenAI retires o3 on 11 Dec 2026; the named replacement is GPT-5.6 Sol. Reasoning model, billed reasoning tokens count as output and can dominate the bill.
What it costs at real volumes
A chat-shaped workload: 800 input tokens and 300 output tokens per request, no caching, no batch.
Specifications
- Provider
- OpenAI
- Context window
- 200K tokens
- Max output
- 100K tokens
- Tier
- Flagship
- Status
- Retires on 11 Dec 2026, replacement GPT-5.6 Sol
- Blended $/1M (3:1)
- $3.50
- Cache break-even, caching each turn
- 0%, caching always saves
- Prices verified
- 30 Oct 2026
Source: OpenAI pricing. Finitizer is not affiliated with OpenAI.
Similar models
Other GPT models
- GPT-6 Astra+$16.50
- GPT-6.1 Sol+$0.500
- GPT-6.1 Terra-$1.50
- GPT-6 Luna-$3.30
- GPT-5.6 Sol+$4.50
- GPT-5.6 Terra+$1.00
- GPT-5.6 Luna-$3.05
- GPT-5-$0.063
- GPT-5 mini-$2.81
- GPT-5 nano-$3.36
- GPT-4.1same price
- GPT-4.1 mini-$2.80
- GPT-4.1 nano-$3.33
- GPT-4o+$0.875
- GPT-4o mini-$3.24
- o4-mini-$1.57
Closest prices elsewhere
- Claude Sonnet 5.5+$0.500
- Gemini 4 Argon+$0.500
- Mistral Medium 3.5-$0.500
- Grok 4.7-$0.500
Frequently asked questions
How much does o3 cost per 1M tokens?
o3 costs $2.00 per million input tokens and $8.00 per million output tokens at OpenAI list prices. Output is 4.0x the input rate, so the input:output ratio of a workload drives the real cost more than the headline price.
Does o3 support prompt caching?
Yes. Cached input is billed at $0.500 per million tokens, 4x cheaper than uncached input. There is no cache-write premium, so caching is never a net loss.
What is the batch discount for o3?
Requests submitted through the asynchronous batch endpoint are billed at 50% off both input and output rates, bringing input to $1.00 and output to $4.00 per million tokens.
What is o3's context window?
200K tokens of context with up to 100K output tokens per request. A larger context window raises the ceiling on what you can send, not the price per token, but filling it on every request is one of the most common causes of an unexpected bill.
Running o3 in production?
Finitizer Tokenomics reads what this model actually costs you from your own bills and exports, shows which workload, team or API key is spending it, flags a spike or a new spend source the day your data shows it, and forecasts where the month will land.
See Finitizer Tokenomics