OpenAI: GPT-5.3 Chat
GPT-5.3 Chat is a language model from OpenAI released on Mar 1, 2026. It reads text and writes text, with a 128K token context window and up to 16K tokens per reply.
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It costs $1.75 per million input tokens and $14 per million output tokens.
It supports tool calling.
4 providers serve it, including 302.AI, Abacus and Merge Gateway.
- Modalities
- In / out price
- $1.75 / $14 per 1M
- Context
- 128K
- Max output
- 16K
- Released
- Mar 1, 2026
- Knowledge cutoff
- Aug 2025
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
GPT-5.3 Chat pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $1.75 / 1M tokens | |
|---|---|---|
| Output | $14 / 1M tokens |
GPT-5.3 Chat providers
4 providers serve it, including 302.AI, Abacus and Merge Gateway. Each host sets its own price and limits, so the cheapest one is not always the one with the longest context.
| Provider | Input /M | Output /M | Cache read /M | Context | Max output |
|---|---|---|---|---|---|
| 302.AI | $1.75 | $14 | – | 128K | 16K |
| Abacus | $1.75 | $14 | – | 400K | 128K |
| Merge Gateway | $1.75 | $14 | $0.175 | 128K | 16K |
| ZenMux | $1.75 | $14 | – | 128K | 16K |
What GPT-5.3 Chat costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call GPT-5.3 Chat through an OpenAI compatible API.
- Tools
tools - Temperature
temperature
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GPT-5.3 Chat questions
How much does the GPT-5.3 Chat API cost?
$1.75 per million input tokens and $14 per million output tokens. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of GPT-5.3 Chat?
128,000 tokens of input, and it can write up to 16,380 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Which providers serve GPT-5.3 Chat?
4 providers serve it, including 302.AI, Abacus and Merge Gateway. Prices differ by host, so the Providers table on this page lists each one with its input and output price.
Does GPT-5.3 Chat support tool calling?
Yes. It accepts tool definitions, which is what an agent needs to call your APIs.
Is GPT-5.3 Chat open source?
No. OpenAI serves it through an API only, so you cannot download the weights or host it yourself.
When was GPT-5.3 Chat released?
Mar 1, 2026, with training data up to Aug 2025.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.
Building on GPT-5.3 Chat?
I test your real tasks on it and the two closest alternatives, then ship the agent on whichever wins on cost and accuracy.
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