Grok 4.3 Beta
Grok 4.3 Beta is an API-only (closed weights) language model from xAI, released April 17, 2026. Its makers disclosed about 500B parameters. The context window is 1M tokens. On the Epoch Capabilities Index it scores 149.9, rank 71 of 256 rated models. API price: $1.25 input / $2.5 output per million tokens.
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Lab
xAI
Released
April 17, 2026
Weights
API-only (closed weights)
Parameters
500B disclosed
Context
1M
Price / M tokens
$1.25 / $2.5 in / out
Epoch ECI
149.9 #71
Strengths by category
ModelTape's 0–100 fit on Epoch AI benchmark results.
| Category | Score | Based on |
|---|---|---|
| Math | 36.7 | ProofBench, OTIS Mock AIME 2024-2025, FrontierMath-Tiers-1-3-v2-Private, FrontierMath-Tier-4-v2-Private |
| Knowledge | 70.1 | GPQA diamond, SimpleQA Verified |
Benchmark results
| Benchmark (Epoch AI) | Score |
|---|---|
| OTIS Mock AIME | 93.3% |
| GPQA Diamond | 88.6% |
| FrontierMath (Tiers 1–3) | 45.1% |
| SimpleQA Verified | 33.2% |
| FrontierMath-Tier-4-v2-Private | 14.6% |
| Chess Puzzles | 13.7% |
| ProofBench | 11.0% |
Links
Announcement · Epoch AI benchmarks
Models with a similar score
GLM-5.3-Flash · Muse Spark · GLM-5.2 · Gemini 3 Pro · Claude Sonnet 4.6 · Mistral Large 4 Preview · Qwen 3.8 27B · Gemini 3 Flash
More from xAI
Grok 4.7 · Grok 4.6 · Grok 4.5 · Grok Build 0.1 · Grok 4.20 Multi-Agent · Grok 4.20 · Grok 4.1 Fast · Grok 4.1