GPT-5.4 mini vs Kimi K2.5 vs Grok 4.3
Too close to call on our weighted score (Grok 4.3 67, Kimi K2.5 65, GPT-5.4 mini 63). The right pick depends on what you value most.
OpenAIGPT-5.4 mini
63/100- ECI148.8
- Price$0.75 / $4.50
- Context400K
Moonshot AIKimi K2.5
65/100- ECI148.0
- Price$0.60 / $3.00
- Context262K
xAIGrok 4.3
67/100- ECI149.2
- Price$1.25 / $2.50
- Context1M
Too close to call
It is close. Our weighted score puts them within 2 points (Grok 4.3 67/100, Kimi K2.5 65/100, GPT-5.4 mini 63/100), so choose by what matters most for your work: Grok 4.3 for raw capability and Kimi K2.5 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGrok 4.3Capabilities Index (ECI): Grok 4.3 149.2 · GPT-5.4 mini 148.8 · Kimi K2.5 148.0
- Lowest priceKimi K2.5Kimi K2.5 $1.20 · Grok 4.3 $1.56 · GPT-5.4 mini $1.69 per 1M tokens (3:1 blend)
- Longest contextGrok 4.3Grok 4.3 1,000,000 · GPT-5.4 mini 400,000 · Kimi K2.5 262,144 tokens
- Widest inputsKimi K2.5 and Grok 4.3GPT-5.4 mini: Text, Images · Kimi K2.5: Text, Images, Video · Grok 4.3: Text, Images, PDFs
- Self-hostingKimi K2.5Publishes downloadable weights
| Measure | Weight | GPT-5.4 mini | Kimi K2.5 | Grok 4.3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 77 | 76 | 77 |
| Price | 25% | 39 | 46 | 41 |
| Inputs & features | 15% | 70 | 80 | 80 |
| Context window | 10% | 44 | 37 | 60 |
| Overall | 100% | 63/100 | 65/100 | 67/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.4 miniOpenAI | Kimi K2.5Moonshot AI | Grok 4.3xAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 148.8 | 148.0 | 149.2 (best) |
| ECI rank | #56 of 148 | #58 of 148 | #55 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 86.9% | 87.6% | 88.8% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 51.2% (best) | — | 42.8% |
| OTIS Mock AIME 2024–2025Competition mathematics | 88.9% | 92.2% | 93.3% (best) |
| SWE-bench VerifiedFixing real GitHub issues | — | 73.8% | — |
| SimpleQA VerifiedShort factual questions | 29.4% | 34.3% (best) | 33.2% |
| Price per million tokens | |||
| Input | $0.75 | $0.60 (best) | $1.25 |
| Output | $4.50 | $3.00 | $2.50 (best) |
| Cached input | $0.075 (best) | — | $0.20 |
| Blended (3:1) | $1.69 | $1.20 (best) | $1.56 |
| Long-context rate | Same rate | Same rate | Over 200K: $2.50 / $5.00 |
| Price source | Official OpenAI API | Median of 21 providers | Official xAI API |
| Limits | |||
| Context window | 400,000 tokens | 262,144 tokens | 1,000,000 tokens (best) |
| Max output | 128,000 tokens | 262,144 tokens (best) | 30,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | No | Yes |
| Audio | No | No | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · medium · high · xhigh | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | gpt-5.4-mini | — | grok-4.3 |
| API providers | 29 (best) | 21 | 27 |
| Released | Mar 17, 2026 | Jan 27, 2026 | Apr 17, 2026 |
| Knowledge cutoff | Aug 31, 2025 | 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.
- GPT-5.4 mini$16.50
- Kimi K2.5$12.00
- Grok 4.3$17.50
Which should you choose?
Which is better: GPT-5.4 mini, Kimi K2.5 or Grok 4.3?
It is close. Our weighted score puts them within 2 points (Grok 4.3 67/100, Kimi K2.5 65/100, GPT-5.4 mini 63/100), so choose by what matters most for your work: Grok 4.3 for raw capability and Kimi K2.5 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.4 mini, Kimi K2.5 or Grok 4.3?
Kimi K2.5 is cheaper at $0.60 input / $3.00 output per million tokens (median across 21 API providers). Grok 4.3 costs $1.25 input / $2.50 output per million tokens (official xAI API price); GPT-5.4 mini costs $0.75 input / $4.50 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $1.20 per million tokens for Kimi K2.5 versus $1.56 for Grok 4.3 (1.3× as much) and $1.69 for GPT-5.4 mini (1.4× as much).
Which scores higher on benchmarks?
Grok 4.3 scores higher on the Capabilities Index (ECI): Grok 4.3 149.2 (#55 of 148), GPT-5.4 mini 148.8 (#56 of 148) and Kimi K2.5 148.0 (#58 of 148). The confidence ranges of the top two overlap (147.6–150.8 vs 147.1–150.5), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.3 88.8%, Kimi K2.5 87.6%, GPT-5.4 mini 86.9%; OTIS Mock AIME 2024–2025 — Grok 4.3 93.3%, Kimi K2.5 92.2%, GPT-5.4 mini 88.9%; SimpleQA Verified — Kimi K2.5 34.3%, Grok 4.3 33.2%, GPT-5.4 mini 29.4%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.4 mini and Grok 4.3 yet, so there is no like-for-like coding score. On overall capability, Grok 4.3 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?
Grok 4.3 has the largest context window at 1,000,000 tokens, against 400,000 for GPT-5.4 mini and 262,144 for Kimi K2.5. Maximum output per response: GPT-5.4 mini up to 128,000, Kimi K2.5 up to 262,144, Grok 4.3 up to 30,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.4 mini accepts text and images; Kimi K2.5 accepts text, images and video; Grok 4.3 accepts text, images and PDFs. Kimi K2.5 handles the widest range of inputs.
Are any of these open source?
Kimi K2.5 publishes its weights and can be self-hosted; GPT-5.4 mini and Grok 4.3 is proprietary.
Which is newer?
Grok 4.3 is the newest, released Apr 17, 2026. GPT-5.4 mini came out Mar 17, 2026; Kimi K2.5 came out Jan 27, 2026. Knowledge cutoff: GPT-5.4 mini Aug 31, 2025, Kimi K2.5 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.
