GPT-6 Luna vs Step 5 Preview

Price, context window & benchmark comparison

GPT-6 Luna

OpenAI

$0.10 / $0.50

Input / Output · per 1M tokens

Step 5 Preview

StepFun

$1.00 / $2.70

Input / Output · per 1M tokens

Compare different models

Verdict: GPT-6 Luna is 7.1× cheaper than Step 5 Preview on a typical 3:1 input/output mix. Step 5 Preview scores higher on the Artificial Analysis Intelligence Index (28.5 vs 27.8). GPT-6 Luna has the larger context window (1.1M vs 1M).

	GPT-6 Luna	Step 5 Preview
Input price / 1M	$0.10	$1.00
Output price / 1M	$0.50	$2.70
Blended price (3:1)	$0.20	$1.43
Cached input / 1M	$0.01	$0.10
Context window	1.1M	1M
Max output	128K	64K
Intelligence index	27.8	28.5
Coding index	—	—
Providers	7	—
Best provider uptime (30m)	100.0%	—
Vision input	Yes	Yes
Reasoning	Yes	Yes
Tool calling	Yes	Yes
Released	2026-09-22	2026-10-08
Retirement	—	—

Cost calculator

Input tokens / requestOutput tokens / requestRequests / day

FAQ

Which is cheaper, GPT-6 Luna or Step 5 Preview?

GPT-6 Luna is 7.1× cheaper than Step 5 Preview on a typical 3:1 input/output mix.

GPT-6 Luna vs Step 5 Preview: which has a bigger context window?

GPT-6 Luna: 1,050,000 tokens. Step 5 Preview: 1,048,576 tokens.

How much would 1 million requests cost?

At 2,000 input + 500 output tokens per request: GPT-6 Luna ≈ $450.00, Step 5 Preview ≈ $3,350.

GPT-6 Luna vs Step 5 Preview

GPT-6 Luna

Step 5 Preview

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