GLM-5.3-Flash vs GPT-6 Luna vs Inkling Small

GPT-6 Luna is the better all-round choice, scoring 84/100 against GLM-5.3-Flash (79) and Inkling Small (69). It leads on capability and price. GLM-5.3-Flash wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025), because GPT-6 Luna has no Capabilities Index score yet.

GPT-6 Luna is cheaper at $0.10 input / $0.50 output per million tokens (official OpenAI API price). GLM-5.3-Flash costs $0.15 input / $0.50 output per million tokens (official Z.AI API price); Inkling Small costs $0.50 input / $1.20 output per million tokens (median across 11 API providers). At a typical mix of three input tokens to one output token, that is $0.20 per million tokens for GPT-6 Luna versus $0.237 for GLM-5.3-Flash (1.2× as much) and $0.675 for Inkling Small (3.4× as much).

Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025): GPT-6 Luna 89.4%, GLM-5.3-Flash 79.9% and Inkling Small 74.9%. On individual benchmarks: GPQA Diamond — GPT-6 Luna 90.5%, GLM-5.3-Flash 90.2%, Inkling Small 88.5%; FrontierMath Tiers 1–3 — GPT-6 Luna 79.0%, GLM-5.3-Flash 55.8%, Inkling Small 46.3%; OTIS Mock AIME 2024–2025 — GPT-6 Luna 98.9%, GLM-5.3-Flash 93.9%, Inkling Small 90.0%.

There are no published SWE-bench Verified results for GLM-5.3-Flash, GPT-6 Luna and Inkling Small yet, so there is no like-for-like coding score. On overall capability, GPT-6 Luna leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

GPT-6 Luna and Inkling Small have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for GLM-5.3-Flash. Maximum output per response: GLM-5.3-Flash up to 131,072, GPT-6 Luna up to 128,000, Inkling Small up to 1,048,576 tokens.

GLM-5.3-Flash accepts text, images, PDFs and video; GPT-6 Luna accepts text, images and PDFs; Inkling Small accepts text, images and audio. GLM-5.3-Flash handles the widest range of inputs.

GLM-5.3-Flash and Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; GPT-6 Luna is proprietary.

GPT-6 Luna is the newest, released Sep 22, 2026. GLM-5.3-Flash came out Aug 26, 2026; Inkling Small came out Jul 30, 2026. Knowledge cutoff: GPT-6 Luna May 18, 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 Oct 4, 2026.