Cheaper overall
GLM 5.1
52% lower blended rate
Higher benchmark scores
GPT-5.6 Terra
leads on 11 of 14 figures
Bigger context window
GPT-5.6 Terra
1,050,000 vs 200,000 tokens
Cheaper cached input
GPT-5.6 Terra
$0.20 vs $0.26, 23% less
Where each one wins
GPT-5.6 Terra
- Cheaper cached input $0.20 vs $0.26, 23% less
- Larger context window 1,050,000 tokens
- Higher overall intelligence (Intelligence Index) 42.1 vs 26.1
- Higher coding ability (Coding Index) 76.7 vs 55.8
- Higher multi-step tool use (Agentic Index) 43.2 vs 23.9
- Ahead on 8 more benchmark figures
- Offers Batch, Flex and Priority pricing not listed for GLM 5.1
GLM 5.1
- Cheaper input tokens $1.40 vs $2.00, 30% less
- Cheaper output tokens $4.40 vs $12.00, 63% less
- Cheaper on all four workloads
- Higher instruction following (IFBench) 76.3 vs 71.2
- Higher support-agent performance (ฯยฒ-Bench Telecom) 97.7 vs 86.3
- Higher answer reliability (Omniscience Non-Hallucination) 70.1 vs 12.1
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 1.8 times, from $0.0036 against $0.0080 on a chat turn to $0.2736 against $0.3680 on a long document.
| Workload | GPT-5.6 Terra | GLM 5.1 | ร1,000 | Difference |
|---|---|---|---|---|
| Chat turn 1,000 in / 500 out | $0.0080 | $0.0036 | $8.00 / $3.60 | GLM 5.1 is 55% cheaper |
| RAG answer 10,000 in / 800 out | $0.0296 | $0.0175 | $29.60 / $17.52 | GLM 5.1 is 41% cheaper |
| Agent loop 32,000 in / 700 out ร 20 calls | $0.3680 | $0.2736 | $368.00 / $273.60 | GLM 5.1 is 26% 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 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-5.6 Terra's input goes from $2.00 to $4.00. It does not change which of the two is cheaper.
| Context band | Price | GPT-5.6 Terra | GLM 5.1 | Difference |
|---|---|---|---|---|
| Prompts up to 272,000 tokens | Input | $2.00 | $1.40 | GLM 5.1 is 30% cheaper |
| Prompts up to 272,000 tokens | Cached input | $0.20 | $0.26 | GPT-5.6 Terra is 23% cheaper |
| Prompts up to 272,000 tokens | Output | $12.00 | $4.40 | GLM 5.1 is 63% cheaper |
| Prompts over 272,000 tokens | Input | $4.00 | $1.40 | GLM 5.1 is 65% cheaper |
| Prompts over 272,000 tokens | Cached input | $0.40 | $0.26 | GLM 5.1 is 35% cheaper |
| Prompts over 272,000 tokens | Output | $18.00 | $4.40 | GLM 5.1 is 76% cheaper |
Blended: GPT-5.6 Terra $4.50, GLM 5.1 $2.15 per 1M โ one rate at 3:1 input to output, for comparing two models at a glance.
GPT-5.6 Terra priced by OpenAI, GLM 5.1 by Z.ai. Standard tier, pay-as-you-go.
Other pricing tiers
Only GPT-5.6 Terra 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 | GPT-5.6 Terra | GLM 5.1 | Cheaper |
|---|---|---|---|
| Batch only on GPT-5.6 Terra | $1.00 in / $6.00 out 50% off Standard | Not offered | — |
| Flex only on GPT-5.6 Terra | $1.00 in / $6.00 out 50% off Standard | Not offered | — |
| Priority only on GPT-5.6 Terra | $4.00 in / $24.00 out | Not offered | — |
Benchmarks
They share 14 figures: GPT-5.6 Terra leads on 11, GLM 5.1 on 3. The widest gap is 58 points, on answer reliability (Omniscience Non-Hallucination).
Overall intelligence
Intelligence Index โ Overall intelligence across reasoning, knowledge & math evals
GPT-5.6 Terra ahead by 16
Coding ability
Coding Index โ Coding ability across software-engineering evals
GPT-5.6 Terra ahead by 20.9
Multi-step tool use
Agentic Index โ Tool use & multi-step agent task performance
GPT-5.6 Terra ahead by 19.3
Graduate-level science
GPQA Diamond โ Graduate-level questions in biology, chemistry & physics
GPT-5.6 Terra ahead by 5.7
Expert-exam performance
Humanity's Last Exam โ Expert-level questions across many academic domains
GPT-5.6 Terra ahead by 12.8
Instruction following
IFBench โ Precise following of detailed instructions
GLM 5.1 ahead by 5.1
Support-agent performance
ฯยฒ-Bench Telecom โ Tool-using agent tasks in a telecom support setting
GLM 5.1 ahead by 11.4
Long-context reasoning
AA-LCR โ Long-context reasoning across large inputs
GPT-5.6 Terra ahead by 9.3
Scientific coding
SciCode โ Research-level scientific coding tasks
GPT-5.6 Terra ahead by 10.2
Command-line work
Terminal-Bench Hard โ Complex command-line and terminal workflows
GPT-5.6 Terra ahead by 19.7
Physics research reasoning
CritPt โ Unpublished physics research reasoning problems
GPT-5.6 Terra ahead by 25.4
Real-world task performance
GDPval โ Economically valuable, real-world knowledge work
GPT-5.6 Terra ahead by 16.4
Factual accuracy
Omniscience Accuracy โ Breadth of factual knowledge across domains
GPT-5.6 Terra ahead by 21.6
Answer reliability
Omniscience Non-Hallucination โ How reliably the model avoids fabricated answers
GLM 5.1 ahead by 58
Each figure is that model's best published run, with the effort level named beside it โ where these scores come from.
Specifications
GPT-5.6 Terra holds 850,000 more input tokens in one request. GPT-5.6 Terra also takes file and image. Only GPT-5.6 Terra lists code execution; only GLM 5.1 lists open weights.
| Specification | GPT-5.6 Terra | GLM 5.1 |
|---|---|---|
| Context window | 1,050,000 tokens | 200,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Takes in | Text, image, file | Text |
| Puts out | Text | Text |
| Knowledge cutoff | 16 Feb 2026 | โ |
| Released | 9 Jul 2026 | 7 Apr 2026 |
| Status | Active | Active |
| Sold by | OpenAI, Perplexity | Z.ai |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Web search | Not listed | Not listed |
| Prompt caching | Yes | Yes |
| Code execution | Yes | Not listed |
| Computer use | Not listed | Not listed |
| Open weights | Not listed | Yes |
| Reasoning | Yes | Yes |
FAQs
- Is GPT-5.6 Terra cheaper than GLM 5.1?
- No โ the other way round. A 1,000-token prompt with a 500-token reply costs $0.0080 on GPT-5.6 Terra and $0.0036 on GLM 5.1, and the same model is cheaper on every workload on this page.
- How much do GPT-5.6 Terra and GLM 5.1 cost per 1M tokens?
- GPT-5.6 Terra costs $2.00 for input and $12.00 for output. GLM 5.1 costs $1.40 and $4.40. Standard pay-as-you-go rates, as of 30 Jul 2026.
- Which is better, GPT-5.6 Terra or GLM 5.1?
- On published benchmarks, GPT-5.6 Terra. It leads on 11 of the 14 figures both models report, including overall intelligence (Intelligence Index), where it scores 42.1 against 26.1.
- Does GPT-5.6 Terra or GLM 5.1 offer batch pricing?
- GPT-5.6 Terra only. Its batch input costs $1.00, 50% off its standard rate, and GLM 5.1 lists no batch tier at all.
- Does GPT-5.6 Terra or GLM 5.1 have a bigger context window?
- GPT-5.6 Terra, at 1,050,000 tokens against 200,000. That is 850,000 more input tokens in a single request.