GPT-5.5 Pro vs GLM 5.3 Flash
| Signal | GPT-5.5 Pro | Delta | GLM 5.3 Flash |
|---|---|---|---|
Capabilities | 100 | +17 | |
Benchmarks | 92 | +8 | |
Pricing | 5 | -95 | |
Context window size | 96 | -1 | |
Recency | 100 | -- | |
Output Capacity | 82 | 0 | |
| Overall Result | 2 wins | of 6 | 3 wins |
Score History
92.7
current score
GPT-5.5 Pro
right now
83.6
current score
GPT-5.5 Pro
OpenAI
GLM 5.3 Flash
Zhipu AI
GLM 5.3 Flash saves you $11980.00/month
That's $143760.00/year compared to GPT-5.5 Pro at your current usage level of 100K calls/month.
| Metric | GPT-5.5 Pro | GLM 5.3 Flash | Winner |
|---|---|---|---|
| Overall Score | 93 | 84 | GPT-5.5 Pro |
| Rank | #11 | #68 | GPT-5.5 Pro |
| Quality Rank | #11 | #68 | GPT-5.5 Pro |
| Adoption Rank | #11 | #68 | GPT-5.5 Pro |
| Parameters | -- | -- | -- |
| Context Window | 1050K | 1311K | GLM 5.3 Flash |
| Pricing | $30.00/$180.00/M | $0.07/$0.25/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 83 | GPT-5.5 Pro |
| Benchmarks | 92 | 84 | GPT-5.5 Pro |
| Pricing | 5 | 100 | GLM 5.3 Flash |
| Context window size | 96 | 97 | GLM 5.3 Flash |
| Recency | 100 | 100 | GPT-5.5 Pro |
| Output Capacity | 82 | 82 | GLM 5.3 Flash |
Our score (0-100) is driven by benchmark performance (90%) from Arena Elo ratings, MMLU, GPQA, HumanEval, SWE-bench, and 15+ standardized evaluations. Capabilities and context window serve as tiebreakers (10%). Learn more about our methodology.
Scores 93/100 (rank #11), placing it in the top 97% of all 290 models tracked.
Scores 84/100 (rank #68), placing it in the top 77% of all 290 models tracked.
GPT-5.5 Pro has a 9-point advantage, which typically translates to noticeably better performance on complex reasoning, code generation, and multi-step tasks.
Choose GPT-5.5 Pro when you need:
- Step-by-step reasoning and chain-of-thought problem solving
Choose GLM 5.3 Flash when you need:
- High-volume production workloads where API costs must be minimized
- Step-by-step reasoning and chain-of-thought problem solving
- Self-hosted deployments where you need full control over the model
GLM 5.3 Flash offers 100% better value per quality point. At 1M tokens/day, you'd spend $4.88/month with GLM 5.3 Flash vs $3150.00/month with GPT-5.5 Pro - a $3145.13 monthly difference.
Both models have comparable response speeds. For most applications, the latency difference is negligible.
When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.
Code generation & review
Based on overall model capabilities and architecture for coding tasks like generating functions, debugging, and refactoring
Customer support chatbot
Suitable for user-facing chat with competitive response times. GLM 5.3 Flash also offers lower per-token costs for high-volume support
Long document analysis
Larger context window (1311K tokens) can process longer documents, contracts, and research papers in a single pass
Batch data extraction
Lower output pricing ($0.25/M) reduces costs when processing thousands of records daily
Creative writing & content
Higher overall composite score (93/100) correlates with better nuance, coherence, and style in long-form content
Image understanding & OCR
Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly
GPT-5.5 Pro has a moderate advantage with a 9.100000000000009-point lead in composite score. It wins on more signal dimensions, but GLM 5.3 Flash has specific strengths that could make it the better choice for certain workflows.
By Use Case
Best for Quality
GPT-5.5 Pro
Marginally better benchmark scores; both are excellent
Best for Cost
GLM 5.3 Flash
100% lower pricing; better value at scale
Best for Reliability
GPT-5.5 Pro
Higher uptime and faster response speeds
Best for Prototyping
GPT-5.5 Pro
Stronger community support and better developer experience
Best for Production
GPT-5.5 Pro
Wider enterprise adoption and proven at scale
by OpenAI
- Choose for Quality - Marginally better benchmark scores; both are excellent
- Choose for Reliability - Higher uptime and faster response speeds
- Choose for Prototyping - Stronger community support and better developer experience
- Choose for Production - Wider enterprise adoption and proven at scale
| Capability | GPT-5.5 Pro | GLM 5.3 Flash |
|---|---|---|
| Vision (Image Input) | ||
| Function Calling | ||
| Streaming | ||
| JSON Mode | ||
| Reasoning | ||
| Web Searchdiffers | ||
| Image Output |
GPT-5.5 Pro
OpenAI
GLM 5.3 Flash
Zhipu AI
GLM 5.3 Flash saves you $269.56/month
That's 100% cheaper than GPT-5.5 Pro at 1,000 tokens/request and 100 requests/day.
Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.
| Parameter | GPT-5.5 Pro | GLM 5.3 Flash |
|---|---|---|
| Context Window | 1.1M | 1.3M |
| Max Output Tokens | 128,000 | 131,072 |
| Open Source | No | Yes |
| Created | Apr 24, 2026 | Aug 26, 2026 |