Gemini 3.5 Flash vs GLM-5.3 vs Grok 4.5
Gemini 3.5 Flash comes out ahead, 69 to 64 and 64 on our weighted score, though GLM-5.3 is 36% cheaper per token.
- Our pick
GoogleGemini 3.5 Flash
69/100- ECI154.5
- Price$1.50 / $9.00
- Context1.05M
Z.ai (Zhipu)GLM-5.3
64/100- ECI155.8
- Price$1.40 / $4.40
- Context1M
xAIGrok 4.5
64/100- ECI154.0
- Price$2.00 / $6.00
- Context500K
Gemini 3.5 Flash is our pick
Gemini 3.5 Flash is the better all-round choice, scoring 69/100 against GLM-5.3 (64) and Grok 4.5 (64). It leads on inputs & features. GLM-5.3 wins on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGLM-5.3Capabilities Index (ECI): GLM-5.3 155.8 · Gemini 3.5 Flash 154.5 · Grok 4.5 154.0
- Lowest priceGLM-5.3GLM-5.3 $2.15 · Grok 4.5 $3.00 · Gemini 3.5 Flash $3.38 per 1M tokens (3:1 blend)
- Longest contextGemini 3.5 FlashGemini 3.5 Flash 1,048,576 · GLM-5.3 1,000,000 · Grok 4.5 500,000 tokens
- Widest inputsGemini 3.5 FlashGemini 3.5 Flash: Text, Images, PDFs, Audio, Video · GLM-5.3: Text · Grok 4.5: Text, Images
- Self-hostingGLM-5.3Publishes downloadable weights
| Measure | Weight | Gemini 3.5 Flash | GLM-5.3 | Grok 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 85 | 83 |
| Price | 25% | 25 | 34 | 27 |
| Inputs & features | 15% | 100 | 45 | 70 |
| Context window | 10% | 61 | 60 | 48 |
| Overall | 100% | 69/100 | 64/100 | 64/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Gemini 3.5 FlashGoogle | GLM-5.3Z.ai (Zhipu) | Grok 4.5xAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 154.5 | 155.8 (best) | 154.0 |
| ECI rank | #33 of 148 | #24 of 148 (best) | #36 of 148 |
| GPQA DiamondGraduate-level science questions | 92.8% | 90.9% | 93.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 62.8% | 68.8% (best) | 57.2% |
| OTIS Mock AIME 2024–2025Competition mathematics | 95.6% | 91.1% | 97.8% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 79.3% | — | — |
| SimpleQA VerifiedShort factual questions | 66.2% (best) | 41.0% | 48.3% |
| Price per million tokens | |||
| Input | $1.50 | $1.40 (best) | $2.00 |
| Output | $9.00 | $4.40 (best) | $6.00 |
| Cached input | $0.15 (best) | $0.26 | $0.30 |
| Blended (3:1) | $3.38 | $2.15 (best) | $3.00 |
| Long-context rate | Same rate | Same rate | Over 200K: $4.00 / $12.00 |
| Price source | Official Google API | Official Z.AI API | Official xAI API |
| Limits | |||
| Context window | 1,048,576 tokens (best) | 1,000,000 tokens | 500,000 tokens |
| Max output | 65,536 tokens | 131,072 tokens | 500,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | No | Yes |
| PDFs | Yes | No | No |
| Audio | Yes | No | No |
| Video | Yes | No | No |
| Reasoning | Yesminimal · low · medium · high | Yeslow · high · max | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | gemini-3.5-flash | glm-5.3 | grok-4.5 |
| API providers | 32 | 62 (best) | 24 |
| Released | May 19, 2026 | Aug 14, 2026 | Jul 8, 2026 |
| Knowledge cutoff | Jan 2025 | — | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Gemini 3.5 Flash$33.00
- GLM-5.3$22.80
- Grok 4.5$32.00
Which should you choose?
Which is better: Gemini 3.5 Flash, GLM-5.3 or Grok 4.5?
Gemini 3.5 Flash is the better all-round choice, scoring 69/100 against GLM-5.3 (64) and Grok 4.5 (64). It leads on inputs & features. GLM-5.3 wins on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Gemini 3.5 Flash, GLM-5.3 or Grok 4.5?
GLM-5.3 is cheaper at $1.40 input / $4.40 output per million tokens (official Z.AI API price). Grok 4.5 costs $2.00 input / $6.00 output per million tokens (official xAI API price); Gemini 3.5 Flash costs $1.50 input / $9.00 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $2.15 per million tokens for GLM-5.3 versus $3.00 for Grok 4.5 (1.4× as much) and $3.38 for Gemini 3.5 Flash (1.6× as much).
Which scores higher on benchmarks?
GLM-5.3 scores higher on the Capabilities Index (ECI): GLM-5.3 155.8 (#24 of 148), Gemini 3.5 Flash 154.5 (#33 of 148) and Grok 4.5 154.0 (#36 of 148). The confidence ranges of the top two overlap (153.7–158.3 vs 152.5–156.6), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.5 93.4%, Gemini 3.5 Flash 92.8%, GLM-5.3 90.9%; FrontierMath Tiers 1–3 — GLM-5.3 68.8%, Gemini 3.5 Flash 62.8%, Grok 4.5 57.2%; OTIS Mock AIME 2024–2025 — Grok 4.5 97.8%, Gemini 3.5 Flash 95.6%, GLM-5.3 91.1%; SimpleQA Verified — Gemini 3.5 Flash 66.2%, Grok 4.5 48.3%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GLM-5.3 and Grok 4.5 yet, so there is no like-for-like coding score. On overall capability, GLM-5.3 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3.5 Flash has the largest context window at 1,048,576 tokens, against 1,000,000 for GLM-5.3 and 500,000 for Grok 4.5. Maximum output per response: Gemini 3.5 Flash up to 65,536, GLM-5.3 up to 131,072, Grok 4.5 up to 500,000 tokens.
Which can read images, PDFs, audio or video?
Gemini 3.5 Flash accepts text, images, PDFs, audio and video; GLM-5.3 accepts text; Grok 4.5 accepts text and images. Gemini 3.5 Flash handles the widest range of inputs.
Are any of these open source?
GLM-5.3 publishes its weights and can be self-hosted; Gemini 3.5 Flash and Grok 4.5 is proprietary.
Which is newer?
GLM-5.3 is the newest, released Aug 14, 2026. Grok 4.5 came out Jul 8, 2026; Gemini 3.5 Flash came out May 19, 2026. Knowledge cutoff: Gemini 3.5 Flash Jan 2025.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
