Model comparison
GPT-6 Luna vs Granite 4.2 8B
GPT-6 Luna is the stronger model overall, scoring 53.3 to 40.5 on the Noometry Index. Granite 4.2 8B costs 1.9× less per token, which makes it the better buy when GPT-6 Luna's lead doesn't matter for your workload.
Last verified . 11 shared benchmarks.
Summary
- They share 11 benchmarks with published results for both. GPT-6 Luna scores higher in 7 categories and Granite 4.2 8B in 0 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-6 Luna leads 48.2 to 26.6.
- Granite 4.2 8B is cheaper at $0.06 / $0.25 per million input/output tokens, against $0.10 / $0.50 for GPT-6 Luna.
- GPT-6 Luna accepts more context: 1.05M tokens versus 131K.
- Granite 4.2 8B has downloadable open weights; the other is API-only.
Side by side
| GPT-6 Luna | Granite 4.2 8B | |
|---|---|---|
| Provider | OpenAI | IBM |
| Noometry Index | 53.3 | 40.5 |
| Released | 2026-09-22 | — |
| Weights | Proprietary | Open |
| Context window | 1.05M | 131K |
| Max output | 128K | 118K |
| Input $ / M tokens | $0.10 | $0.06 |
| Output $ / M tokens | $0.50 | $0.25 |
| Results tracked | 42 | 11 |
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Category by category
Coding GPT-6 Luna leads
GPT-6 Luna: 55.5 (#25), Granite 4.2 8B: 40.5 (#137)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Coding | 1439 | 1380 |
| DeepSWE | 66.6% | — |
| FrontierCode | 42.4% | — |
| LMArena WebDev | 1581 | — |
| SciCode | 54.6% | — |
| ALE-Bench | 1,577 | — |
Agentic & Tool Use Not comparable
GPT-6 Luna: 33.3 (#54), Granite 4.2 8B: —
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| APEX-Agents | 44.3% | — |
| GDP.pdf | 23% | — |
Reasoning GPT-6 Luna leads
GPT-6 Luna: 48.2 (#41), Granite 4.2 8B: 26.6 (#131)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Hard Prompts | 1411 | 1329 |
| ARC-AGI-2 | 59.3% | — |
| NYT Connections (extended) | 68.7% | — |
| ARC-AGI-1 | 86.7% | — |
| CritPt | 19.4% | — |
| Chess Puzzles | 31% | — |
| Mystery Game Puzzles | 7% | — |
| DTBench | 90.1% | — |
| LMCA | 44.5% | — |
| Epoch Capabilities Index | 156.28 | — |
Math Not comparable
GPT-6 Luna: 76.1 (#15), Granite 4.2 8B: —
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| FrontierMath (Tiers 1-3) | 78.9% | — |
| FrontierMath Tier 4 | 56.1% | — |
| OTIS Mock AIME 2024-2025 | 98.9% | — |
| ProofBench | 64% | — |
| LMArena Math | 1416 | — |
Knowledge GPT-6 Luna leads
GPT-6 Luna: 57.0 (#41), Granite 4.2 8B: 38.4 (#145)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Expert | 1444 | 1384 |
| GPQA Diamond | 90.5% | — |
| SimpleQA Verified | 41.4% | — |
Multimodal Not comparable
GPT-6 Luna: 42.4 (#30), Granite 4.2 8B: —
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Vision | 1217 | — |
| Blueprint-Bench 2 | 31.2% | — |
| Furniture Assembly | 44.2% | — |
Multilingual GPT-6 Luna leads
GPT-6 Luna: 50.5 (#117), Granite 4.2 8B: 44.5 (#178)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Non-English | 1386 | 1302 |
| LMArena Chinese | 1433 | 1366 |
| LMArena Russian | 1394 | 1285 |
| LMArena French | 1420 | — |
| LMArena German | 1369 | — |
| LMArena Japanese | 1369 | — |
| LMArena Korean | 1360 | — |
| LMArena Spanish | 1393 | — |
Instruction Following GPT-6 Luna leads
GPT-6 Luna: 74.3 (#99), Granite 4.2 8B: 68.7 (#184)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Instruction Following | 1409 | 1301 |
Long Context GPT-6 Luna leads
GPT-6 Luna: 43.0 (#111), Granite 4.2 8B: 40.3 (#159)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Longer Query | 1409 | 1324 |
Writing & Preference GPT-6 Luna leads
GPT-6 Luna: 58.3 (#119), Granite 4.2 8B: 49.6 (#189)
| Benchmark | GPT-6 Luna | Granite 4.2 8B |
|---|---|---|
| LMArena Text | 1391 | 1320 |
| LMArena Creative Writing | 1363 | 1236 |
| LMArena Multi-Turn | 1396 | 1301 |
Frequently asked questions
Is GPT-6 Luna better than Granite 4.2 8B?
GPT-6 Luna is the stronger model overall, scoring 53.3 to 40.5 on the Noometry Index. Granite 4.2 8B costs 1.9× less per token, which makes it the better buy when GPT-6 Luna's lead doesn't matter for your workload.
Which is cheaper, GPT-6 Luna or Granite 4.2 8B?
Granite 4.2 8B is cheaper. It lists at $0.06 per million input tokens and $0.25 per million output tokens; GPT-6 Luna lists at $0.10 and $0.50.
Is GPT-6 Luna or Granite 4.2 8B better for coding?
GPT-6 Luna scores higher on coding benchmarks: 55.5 versus 40.5 in the Noometry coding category.
Which has the bigger context window?
GPT-6 Luna does, with 1.05M tokens against 131K.
How many benchmarks do GPT-6 Luna and Granite 4.2 8B share?
11 benchmarks have published results for both models. GPT-6 Luna has 42 scored results on Noometry and Granite 4.2 8B has 11.