Granite 4.2 8B Open vs 
GPT-6 Luna Pro Paid
Granite 4.2 8B vs GPT-6 Luna Pro compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
GPT-6 Luna Pro — full profile ›
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
$0.25 /M outputNo per-token fees if you self-host
$0.5 /M outputManaged API (no infra to run)
Granite 4.2 8B vs GPT-6 Luna Pro specs
| Spec | Granite 4.2 8B | GPT-6 Luna Pro | Winner |
|---|---|---|---|
| Maker | IBM | OpenAI | – |
| Type | Open-weight | Proprietary | |
| Context window | 131K tokens | 1.1M tokens | |
| Input price | $0.06/M · free self-host | $0.1/M | |
| Output price | $0.25/M · free self-host | $0.5/M | |
| Vision / multimodal | No | Yes | |
| Tool / function calling | Yes | Yes | = Tie |
| Self-hostable | Yes | No (API only) | |
| License | Apache 2.0 | Proprietary |
Price gap & when to choose each
Granite 4.2 8B is ~2.0× cheaper than GPT-6 Luna Pro on output tokens ($0.25 vs $0.5 per M tokens).
- You want to self-host or run on your cloud
- You prioritize data privacy & control
- You want the lowest operating costs
- You are building open or reproducible AI
- You want frontier performance through a managed API
- You need the longer 1.1M context window
- You value reliability & ecosystem
- You don't want to manage infrastructure
Feature comparison
| Capability | Granite 4.2 8B | GPT-6 Luna Pro |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✗ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✗ | ✓ |
Benchmarks: Granite 4.2 8B vs GPT-6 Luna Pro
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Granite 4.2 8B and GPT-6 Luna Pro score
| Criterion | Granite 4.2 8B | GPT-6 Luna Pro |
|---|---|---|
| Cost-efficiency | 5.0 | 5.0 |
| Context window | 3.5 | 5.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 3.5 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Granite 4.2 8B Open
Granite 4.2 8B is a dense reasoning model from IBM. It is suited for mathematics, code generation, multilingual dialogue, and agentic workflows that need multi-step reasoning. It supports full, low-effort,...
GPT-6 Luna Pro Paid
GPT-6 Luna Pro is the same underlying model as [GPT-6 Luna](https://openrouter.ai/openai/gpt-6-luna), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. **Cost note:** pro mode spends far more...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is Granite 4.2 8B as good as GPT-6 Luna Pro?
Granite 4.2 8B is open-weight and competitive on many tasks, but GPT-6 Luna Pro may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run Granite 4.2 8B locally?
Yes. Granite 4.2 8B has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. GPT-6 Luna Pro is API-only and cannot be self-hosted.
How much cheaper is Granite 4.2 8B?
Granite 4.2 8B costs $0.25/M output vs $0.5/M for GPT-6 Luna Pro — roughly 2x cheaper via API, and free if you self-host.
Granite 4.2 8B vs GPT-6 Luna Pro — which should I pick in 2026?
Choose Granite 4.2 8B if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose GPT-6 Luna Pro if you want frontier capability through a managed API with zero infrastructure to run.
People also compare
Explore more open-source AI
Browse the full open-source model leaderboard, thousands of tools and live benchmarks — all in one place.
Open the leaderboard →