GLM-5.3-Flash vs GPT-5.6 Luna Max compared

GLM-5.3-Flash leads the intelligence index 27.8 to 23.8. GLM-5.3-Flash costs 47% less on blended price. Price per token, response speed and when to pick each.

Metric	GLM-5.3-Flash	GPT-5.6 Luna (Max)
Intelligence Index	27.8	23.8
Input price (per 1M tokens)	$0.15	$0.20
Output price (per 1M tokens)	$0.50	$1.20
Output speed (tokens/s)	56	125
Time to first token	1.6s	108s
Release date	2026-08-26	2026-07-09

Metric

GLM-5.3-Flash

GPT-5.6 Luna (Max)

Intelligence Index

27.8

23.8

Input price (per 1M tokens)

$0.15

$0.20

Output price (per 1M tokens)

$0.50

$1.20

Output speed (tokens/s)

125

Time to first token

1.6s

108s

Release date

2026-08-26

2026-07-09

Choosing between GLM-5.3-Flash and GPT-5.6 Luna (Max) also means choosing between Z AI and OpenAI. What separates them most is responsiveness; GPT-5.6 Luna Max takes 108 seconds to produce its first token, GLM-5.3-Flash 1.6 seconds. Everything below is read from the benchmark, price and speed data in Franklin AI's catalogue; nothing here comes from a hands-on test.

How fast they respond

Measured output speed is 56 tokens per second for GLM-5.3-Flash and 125 tokens per second for GPT-5.6 Luna Max. GPT-5.6 Luna Max is ahead by 123% on throughput. Before any text appears, GLM-5.3-Flash takes 1.6 seconds and GPT-5.6 Luna Max 108 seconds. The faster writer, GPT-5.6 Luna Max, gives away too much at the start to win on time: counting the first-token wait, GLM-5.3-Flash finishes first for any reply shorter than about 11,000 tokens. Waits that long are felt on every chat-style request, though they matter less for batch jobs.

For a 600-token response, first token plus generation comes to roughly 12 seconds on GLM-5.3-Flash and 113 seconds on GPT-5.6 Luna Max.

Generation gap

The release dates are July 9, 2026 for GPT-5.6 Luna Max and August 26, 2026 for GLM-5.3-Flash, about 2 months apart.

What they cost

The list prices are $0.15 in and $0.50 out for GLM-5.3-Flash, and $0.20 in and $1.20 out for GPT-5.6 Luna Max, per million tokens. GPT-5.6 Luna Max costs 2.4 times as much per output token.

Take 1 million input tokens and 200,000 output tokens: that comes to $0.25 on GLM-5.3-Flash and $0.44 on GPT-5.6 Luna Max. A bigger example, a chat app with 50,000 sessions of 800 input and 300 output tokens, costs $13.50 on GLM-5.3-Flash and $26.00 on GPT-5.6 Luna Max: a gap of $12.50. On a 3:1 blend of input to output tokens, that works out to $0.238 versus $0.45 per million.

How the intelligence index compares

The catalogue puts GLM-5.3-Flash at 27.8 and GPT-5.6 Luna Max at 23.8 on its intelligence index. That is a clear margin for an index that averages many evaluations.

Among 109 active scored models, GLM-5.3-Flash sits 63rd and GPT-5.6 Luna Max 70th.

There are no coding or math index scores for either model in the catalogue, which keeps this comparison at the aggregate level.

Cost per point of intelligence

Dividing the blended price by the intelligence index gives a rough cost per point: $0.0085 for GLM-5.3-Flash and $0.019 for GPT-5.6 Luna Max, per million tokens. With the higher score and the lower cost per point, GLM-5.3-Flash is the better value per point on these numbers.

Quick answers

Is GLM-5.3-Flash better than GPT-5.6 Luna Max?

Not across the board: GLM-5.3-Flash scores higher on the intelligence index, 27.8 to 23.8; GLM-5.3-Flash is 47% cheaper on blended price; GPT-5.6 Luna Max streams output 2.2 times as fast; and GLM-5.3-Flash reaches its first token sooner.

Who makes GLM-5.3-Flash and GPT-5.6 Luna Max?

GLM-5.3-Flash is made by Z AI and GPT-5.6 Luna Max by OpenAI. GLM-5.3-Flash was released on August 26, 2026 and GPT-5.6 Luna Max on July 9, 2026.

Which model has lower latency?

GPT-5.6 Luna Max generates output faster, at 125 tokens per second against 56 tokens per second. GLM-5.3-Flash reaches its first token sooner (1.6 seconds against 108 seconds). Counting the first-token wait, GLM-5.3-Flash finishes first for any reply shorter than about 11,000 tokens.

How much do GLM-5.3-Flash and GPT-5.6 Luna Max cost?

GLM-5.3-Flash is cheaper on a blended basis. GLM-5.3-Flash lists $0.15 per million input tokens and $0.50 per million output tokens; GPT-5.6 Luna Max lists $0.20 and $1.20. For 1 million input and 200,000 output tokens that is $0.25 against $0.44.

Where do these numbers come from?

The figures are the recorded benchmark, price and speed data in Franklin AI's model catalogue. This page is written from that data automatically; neither model was tested by hand for it.

Final whistle

Bottom line: on balance the numbers favour GLM-5.3-Flash, though GPT-5.6 Luna Max keeps a case of its own. Pick GPT-5.6 Luna Max if you generate very long outputs, beyond about 11,000 tokens. Pick GLM-5.3-Flash if users are waiting on the first word and you need the higher overall score (27.8 against 23.8).

Where the numbers come from

The scores, speed and prices in this comparison come from independent third-party model evaluations that Franklin AI syncs each day, and the article was written from a snapshot of them. For the latest results, open the GLM-5.3-Flash and GPT-5.6 Luna (Max) pages. The AI Benchmark methodology explains how that data is collected and shown.