GPT-5.6 Sol vs Kimi K3

Both are Flagship-tier models, from OpenAI and Moonshot AI respectively. Kimi K3 is the cheaper choice overall at a 4:1 input:output ratio.

Which is cheaper

Input price: Kimi K3 is cheaper ($3.00 vs $4.00).
Output price: Kimi K3 is cheaper ($15.00 vs $20.00).
Blended, 4:1 input:output ratio: Kimi K3 is 25% cheaper ($5.40 vs $7.20 per weighted 1M tokens).

Side by side

Spec	GPT-5.6 Sol	Kimi K3
Provider	OpenAI	Moonshot AI
Tier	Flagship	Flagship
Context window	1.05M	1.05M
Max output	128K	—
Input $/1M	$4.00	$3.00
Output $/1M	$20.00	$15.00
Cache read $/1M	$0.40	$0.30
Cache write $/1M	$5.00	—
Modalities	text, image	text

GPT-5.6 Sol. Short-context rate, for prompts up to 272K input tokens. Above 272K the rate is $8 input / $30 output, cache read $0.80, cache write $10 per 1M. Promotional pricing, stated to run at least through 21 November 2026.

Kimi K3. input is cache-miss (standard) price per 1M tokens; cache_read is cache-hit price ($0.30).

Sources

GPT-5.6 Sol — verified August 29, 2026

Kimi K3 — verified August 29, 2026

Full GPT-5.6 Sol pricing page → · Full Kimi K3 pricing page →