How much does the OpenAI API cost?

As of June 2026, OpenAI API prices per million tokens are: GPT-5.5 at $5 input / $30 output; GPT-5.5-pro at $30 / $180; GPT-5.4 at $2.50 / $15; GPT-5.4-mini at $0.75 / $4.50; and GPT-5.4-nano at $0.20 / $1.25. Cached input is discounted roughly 90%, and the Batch API takes 50% off.

How much does the ChatGPT API cost per token?

The ChatGPT models are the GPT-5 family on the API. GPT-5.5 (the flagship behind ChatGPT) costs $5 per million input tokens and $30 per million output tokens. For most production use the mid-tier GPT-5.4 at $2.50 / $15 is the better value, and GPT-5.4-nano at $0.20 / $1.25 handles cheap high-volume tasks.

Is the OpenAI API cheaper than Claude?

At the cheap and mid tiers, yes. GPT-5.4-nano ($0.20/$1.25) undercuts Claude Haiku 4.5 ($1/$5), and GPT-5.4 ($2.50/$15) sits between Claude Haiku and Sonnet. At the flagship tier they are close: GPT-5.5 and Claude Opus 4.8 both charge $5 input, with GPT-5.5 at $30 output vs Opus at $25.

OpenAI API pricing (2026): the GPT-5 per-token cost table

Q: What is the cheapest OpenAI API model?

GPT-5.4-nano is the cheapest OpenAI model at $0.20 per million input tokens and $1.25 per million output tokens. Cached input drops the input cost about 90%, and the Batch API halves both input and output, so high-volume classification and routing workloads can run at a fraction of a cent per request.

Short answer: Per million tokens, the OpenAI API costs $5 in / $30 out for GPT-5.5 (the flagship behind ChatGPT), $2.50 in / $15 out for GPT-5.4, $0.75 / $4.50 for GPT-5.4-mini, and $0.20 / $1.25 for GPT-5.4-nano — the cheapest model. GPT-5.5-pro is $30 / $180. Cached input saves ~90% and the Batch API takes 50% off. Verified June 2026.

OpenAI API model pricing (per 1M tokens)

Model	Input	Output	Best for
GPT-5.5-pro	$30	$180	Hardest reasoning, highest-stakes work
GPT-5.5 (flagship)	$5	$30	Production default; the model behind ChatGPT
GPT-5.4	$2.50	$15	Best value mid-tier for most production use
GPT-5.4-mini	$0.75	$4.50	Cost/capability balance at scale
GPT-5.4-nano (cheapest)	$0.20	$1.25	Routing, classification, high-volume simple tasks

Prices are USD per million tokens (MTok) for standard synchronous calls. "ChatGPT API pricing" refers to these GPT-5 models — the consumer ChatGPT product is a separate $20/mo subscription, not per-token billing.

What is the cheapest OpenAI API model?

GPT-5.4-nano, at $0.20 / $1.25 per million tokens, is the cheapest OpenAI model. The effective cost drops further with two stacking discounts:

Cached input: repeated prompt prefixes are discounted ~90%, so long static system prompts cost a fraction of full input.
Batch API: 50% off both input and output for asynchronous, non-time-sensitive jobs.

For tasks where even nano is overkill, compare against Claude Haiku 4.5 and Gemini Flash in API alternatives.

Discounts: cached input and Batch API

Feature	Discount	Applies to
Cached input	~90% off input	Repeated prompt prefixes (e.g. GPT-5.5 cached input ~$0.50)
Batch API	50% off in & out	Async jobs (24-hour window)
Flex / lower-priority	Reduced rate	Latency-tolerant workloads

Worked example: cost of a typical GPT-5.4 request

A request that sends 20,000 input tokens and generates 2,000 output tokens on GPT-5.4:

Input: 20,000 × $2.50 / 1,000,000 = $0.050
Output: 2,000 × $15 / 1,000,000 = $0.030
Total: $0.080 per request

The same request on GPT-5.4-nano costs (20,000 × $0.20 + 2,000 × $1.25) / 1,000,000 = $0.0065 — about 12x cheaper, which is why nano is the right pick for high-volume, low-complexity work.

How OpenAI API pricing compares to Claude

OpenAI tends to win on raw price at the cheap and mid tiers, while the flagships are close. GPT-5.4-nano ($0.20/$1.25) undercuts Claude Haiku 4.5 ($1/$5); GPT-5.4 ($2.50/$15) sits between Haiku and Sonnet 4.6 ($3/$15). At the top, GPT-5.5 and Claude Opus 4.8 both charge $5 input, with GPT-5.5 slightly higher on output ($30 vs $25). Full breakdown: ChatGPT vs Claude API cost and the Anthropic API pricing table.