GLM 5.1 vs GPT-5.4

GLM 5.1 is the cheaper of the two, though not evenly: its output costs 71% less than GPT-5.4's, $4.40 per 1M against $15.00, while its input is only 44% cheaper, $1.40 against $2.50. Caching narrows the gap: over a thousand agent loops, where most of each prompt comes from cache, that is $273.60 against $460.00.

What the extra 162% buys is 15.3 points of coding ability (Coding Index): 71.1 (xhigh) against 55.8 (Reasoning). GLM 5.1 is the one to pick unless you need GPT-5.4's lead on coding ability.

Standard pay-as-you-go prices, as of 7 Apr 2026. Last updated 27 Sep 2026.

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Cheaper overall

GLM 5.1

62% lower blended rate

Higher benchmark scores

GLM 5.1

leads on 14 of 24 figures

Bigger context window

GPT-5.4

1,050,000 vs 200,000 tokens

Cheaper cached input

GPT-5.4

$0.25 vs $0.26, 4% less

Where each one wins

GLM 5.1

  • Cheaper input tokens $1.40 vs $2.50, 44% less
  • Cheaper output tokens $4.40 vs $15.00, 71% less
  • Cheaper on all four workloads
  • Higher instruction following (IFBench) 76.3 vs 73.9
  • Higher support-agent performance (ฯ„ยฒ-Bench Telecom) 97.7 vs 87.1
  • Higher answer reliability (Omniscience Non-Hallucination) 70.1 vs 17.4
  • Ahead on 11 more benchmark figures

GPT-5.4

  • Cheaper cached input $0.25 vs $0.26, 4% less
  • Larger context window 1,050,000 tokens
  • Higher coding ability (Coding Index) 71.1 vs 55.8
  • Higher graduate-level science (GPQA Diamond) 92 vs 86.8
  • Higher expert-exam performance (Humanity's Last Exam) 43.7 vs 30.1
  • Ahead on 7 more benchmark figures
  • Offers Batch, Flex and Priority pricing not listed for GLM 5.1

What four workloads cost

One run, and the same run a thousand times.

GLM 5.1 is cheaper on all four workloads, by much the same margin each time โ€” about 2.2 times, from $0.0036 against $0.0100 on a chat turn to $0.2736 against $0.4600 on a long document.

Workload GLM 5.1 GPT-5.4 ร—1,000 Difference
Chat turn 1,000 in / 500 out $0.0036 $0.0100 $3.60 / $10.00 GLM 5.1 is 64% cheaper
RAG answer 10,000 in / 800 out $0.0175 $0.0370 $17.52 / $37.00 GLM 5.1 is 53% cheaper
Agent loop 32,000 in / 700 out ร— 20 calls $0.2736 $0.4600 $273.60 / $460.00 GLM 5.1 is 41% cheaper
Long document 400,000 in / 3,000 out GLM 5.1's context window holds 200,000 tokens, so a 400,000-token prompt does not fit.

Price your own token counts for these two โ†’

Price per 1M tokens

Above 272,000 input tokens the rates change, and the new rate applies to the whole request, not just the tokens past that point: GPT-5.4's input goes from $2.50 to $5.00. It does not change which of the two is cheaper.

Context band Price GLM 5.1 GPT-5.4 Difference
Prompts up to 272,000 tokens Input $1.40 $2.50 GLM 5.1 is 44% cheaper
Prompts up to 272,000 tokens Cached input $0.26 $0.25 GPT-5.4 is 4% cheaper
Prompts up to 272,000 tokens Output $4.40 $15.00 GLM 5.1 is 71% cheaper
Prompts over 272,000 tokens Input $1.40 $5.00 GLM 5.1 is 72% cheaper
Prompts over 272,000 tokens Cached input $0.26 $0.50 GLM 5.1 is 48% cheaper
Prompts over 272,000 tokens Output $4.40 $22.50 GLM 5.1 is 80% cheaper

Blended: GLM 5.1 $2.15, GPT-5.4 $5.625 per 1M โ€” one rate at 3:1 input to output, for comparing two models at a glance.

GLM 5.1 priced by Z.ai, GPT-5.4 by OpenAI. Standard tier, pay-as-you-go.

Other pricing tiers

Only GPT-5.4 lists Batch, Flex and Priority, at up to 50% off its own standard rate; GLM 5.1 offers none of them.

Every tier either model sells is here, so this is the whole price sheet. A saving is measured against that model's own standard rate โ€” how we read tiers.

Tier GLM 5.1 GPT-5.4 Cheaper
Batch only on GPT-5.4 Not offered $1.25 in / $7.50 out 50% off Standard —
Flex only on GPT-5.4 Not offered $1.25 in / $7.50 out 50% off Standard —
Priority only on GPT-5.4 Not offered $5.00 in / $30.00 out —

Benchmarks

They share 24 figures: GLM 5.1 leads on 14, GPT-5.4 on 10. The widest gap is 216 points, on 3d Elo.

Coding ability

Coding Index โ€” Coding ability across software-engineering evals

GLM 5.1 55.8
GPT-5.4 71.1

GPT-5.4 ahead by 15.3

Graduate-level science

GPQA Diamond โ€” Graduate-level questions in biology, chemistry & physics

GLM 5.1 86.8
GPT-5.4 92

GPT-5.4 ahead by 5.2

Expert-exam performance

Humanity's Last Exam โ€” Expert-level questions across many academic domains

GLM 5.1 30.1
GPT-5.4 43.7

GPT-5.4 ahead by 13.6

Instruction following

IFBench โ€” Precise following of detailed instructions

GLM 5.1 76.3
GPT-5.4 73.9

GLM 5.1 ahead by 2.4

Support-agent performance

ฯ„ยฒ-Bench Telecom โ€” Tool-using agent tasks in a telecom support setting

GLM 5.1 97.7
GPT-5.4 87.1

GLM 5.1 ahead by 10.6

Long-context reasoning

AA-LCR โ€” Long-context reasoning across large inputs

GLM 5.1 73.7
GPT-5.4 82

GPT-5.4 ahead by 8.3

Command-line work

Terminal-Bench Hard โ€” Complex command-line and terminal workflows

GLM 5.1 43.2
GPT-5.4 57.6

GPT-5.4 ahead by 14.4

Physics research reasoning

CritPt โ€” Unpublished physics research reasoning problems

GLM 5.1 4.6
GPT-5.4 23.4

GPT-5.4 ahead by 18.8

Real-world task performance

GDPval โ€” Economically valuable, real-world knowledge work

GLM 5.1 30.2
GPT-5.4 36.6

GPT-5.4 ahead by 6.4

Factual accuracy

Omniscience Accuracy โ€” Breadth of factual knowledge across domains

GLM 5.1 25.2
GPT-5.4 50.8

GPT-5.4 ahead by 25.6

Answer reliability

Omniscience Non-Hallucination โ€” How reliably the model avoids fabricated answers

GLM 5.1 70.1
GPT-5.4 17.4

GLM 5.1 ahead by 52.7

Androidnative Elo

Design Arena head-to-head rating in the androidnative category

GLM 5.1 1,194
GPT-5.4 1,046

GLM 5.1 ahead by 148

Fullstack Elo

Design Arena head-to-head rating in the fullstack category

GLM 5.1 1,166
GPT-5.4 1,016

GLM 5.1 ahead by 150

Godotgamedev Elo

Design Arena head-to-head rating in the godotgamedev category

GLM 5.1 1,053
GPT-5.4 1,135

GPT-5.4 ahead by 82

Mobileapps Elo

Design Arena head-to-head rating in the mobileapps category

GLM 5.1 1,191
GPT-5.4 1,115

GLM 5.1 ahead by 76

Webapps Elo

Design Arena head-to-head rating in the webapps category

GLM 5.1 1,174
GPT-5.4 1,058

GLM 5.1 ahead by 116

3d Elo

Design Arena head-to-head rating in the 3d category

GLM 5.1 1,336
GPT-5.4 1,120

GLM 5.1 ahead by 216

Asciiart Elo

Design Arena head-to-head rating in the asciiart category

GLM 5.1 1,146
GPT-5.4 1,212

GPT-5.4 ahead by 66

Codecategories Elo

Design Arena head-to-head rating in the codecategories category

GLM 5.1 1,276
GPT-5.4 1,221

GLM 5.1 ahead by 55

Dataviz Elo

Design Arena head-to-head rating in the dataviz category

GLM 5.1 1,366
GPT-5.4 1,245

GLM 5.1 ahead by 121

Gamedev Elo

Design Arena head-to-head rating in the gamedev category

GLM 5.1 1,276
GPT-5.4 1,253

GLM 5.1 ahead by 23

Svg Elo

Design Arena head-to-head rating in the svg category

GLM 5.1 1,227
GPT-5.4 1,203

GLM 5.1 ahead by 24

Uicomponent Elo

Design Arena head-to-head rating in the uicomponent category

GLM 5.1 1,292
GPT-5.4 1,248

GLM 5.1 ahead by 44

Website Elo

Design Arena head-to-head rating in the website category

GLM 5.1 1,290
GPT-5.4 1,228

GLM 5.1 ahead by 62

Each figure is that model's best published run, with the effort level named beside it โ€” where these scores come from.

Specifications

GPT-5.4 holds 850,000 more input tokens in one request. GPT-5.4 also takes file and image.

Specification GLM 5.1 GPT-5.4
Context window 200,000 tokens 1,050,000 tokens
Max output 128,000 tokens 128,000 tokens
Takes in Text Text, image, file
Puts out Text Text
Knowledge cutoff โ€” 31 Aug 2025
Released 7 Apr 2026 5 Mar 2026
Status Active Active
Sold by Z.ai OpenAI, Perplexity

FAQs

Is GLM 5.1 cheaper than GPT-5.4?
Yes. A 1,000-token prompt with a 500-token reply costs $0.0036 on GLM 5.1 and $0.0100 on GPT-5.4, and the same model is cheaper on every workload on this page.
How much do GLM 5.1 and GPT-5.4 cost per 1M tokens?
GLM 5.1 costs $1.40 for input and $4.40 for output. GPT-5.4 costs $2.50 and $15.00. Standard pay-as-you-go rates, as of 7 Apr 2026.
Which is better, GLM 5.1 or GPT-5.4?
On published benchmarks, GPT-5.4. It leads on 14 of the 24 figures both models report, including coding ability (Coding Index), where it scores 71.1 against 55.8.
Does GLM 5.1 or GPT-5.4 offer batch pricing?
GPT-5.4 only. Its batch input costs $1.25, 50% off its standard rate, and GLM 5.1 lists no batch tier at all.
Does GLM 5.1 or GPT-5.4 have a bigger context window?
GPT-5.4, at 1,050,000 tokens against 200,000. That is 850,000 more input tokens in a single request.

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