Grok 4.20 (Reasoning) vs Inkling Small

It is close. Our weighted score puts them within a point (Inkling Small 68/100, Grok 4.20 (Reasoning) 67/100), so choose by what matters most for your work: Grok 4.20 (Reasoning) for raw capability, Inkling Small on price and Inkling Small for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Inkling Small is cheaper at $0.58 input / $1.44 output per million tokens (official Thinking Machines API price). Grok 4.20 (Reasoning) costs $1.25 input / $2.50 output per million tokens (official xAI API price). At a typical mix of three input tokens to one output token, that is $0.795 per million tokens for Inkling Small versus $1.56 for Grok 4.20 (Reasoning) (2× as much).

Grok 4.20 (Reasoning) scores higher on the Capabilities Index (ECI): Grok 4.20 (Reasoning) 152.3 (#51 of 165) and Inkling Small 150.5 (#58 of 165). The confidence ranges of the top two overlap (149.5–154.7 vs 147.7–152.4), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.20 (Reasoning) 89.3%, Inkling Small 88.5%; FrontierMath Tiers 1–3 — Inkling Small 46.3%, Grok 4.20 (Reasoning) 44.9%; OTIS Mock AIME 2024–2025 — Grok 4.20 (Reasoning) 92.2%, Inkling Small 90.0%; SimpleQA Verified — Grok 4.20 (Reasoning) 30.2%, Inkling Small 19.1%.

There are no published SWE-bench Verified results for Grok 4.20 (Reasoning) and Inkling Small yet, so there is no like-for-like coding score. On overall capability, Grok 4.20 (Reasoning) leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Inkling Small has the largest context window at 1,048,576 tokens, against 1,000,000 for Grok 4.20 (Reasoning). Maximum output per response: Grok 4.20 (Reasoning) up to 30,000, Inkling Small up to 1,048,576 tokens.

Grok 4.20 (Reasoning) accepts text, images and PDFs; Inkling Small accepts text, images and audio. They handle the same number of input types.

Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; Grok 4.20 (Reasoning) is proprietary.

Inkling Small is the newest, released Jul 30, 2026. Grok 4.20 (Reasoning) came out Mar 9, 2026.

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 Nov 2, 2026.