Grok 4.5 vs GPT-5.6 Terra
Grok 4.5 and GPT-5.6 Terra sit one Intelligence Index point apart — 56 versus 57 — at similar prices: $2/$6 for Grok, $2/$12 for Terra per million tokens. Terra doubles Grok's context window (1M vs 500K) and output speed. Grok's differentiator remains live X data integration; Terra's is ecosystem breadth.
Side by side
| Grok 4.5 | GPT-5.6 Terra | |
|---|---|---|
| Maker | xAI (SpaceX) | OpenAI |
| Released | 2026-07-08 | 2026-07-09 |
| Context window | 512K tokens | 1M tokens |
| Modalities in | text, image | text, image |
| Input $/MTok | $2 | $2 |
| Output $/MTok | $6 | $12 |
| Open weights | No | No |
Benchmark deltas
| Benchmark | Grok 4.5 | GPT-5.6 Terra | Δ |
|---|---|---|---|
| AA Intelligence Index | 56 | 57 | -1 |
Δ is Grok 4.5 minus GPT-5.6 Terra, in points. Shaded cell wins the row. Dashed values are vendor-published, not yet reproduced — methodology.
Cost calculator
- Grok 4.5
- $160/mo
- GPT-5.6 Terra
- $220/mo
- Difference
- $60/mo
List prices as of 2026-08-11; excludes caching, batch, and long-context tiers — see model pages for tier notes.
Verdict
Terra is the safer general-purpose pick: equal input price, one more measured point, twice the context, and 149 tokens per second against Grok's 58. Grok 4.5 wins on output economics — half Terra's per-token output rate — and on its unreplicable asset, native real-time X data, which social-intelligence, market-monitoring, and trend workloads cannot get elsewhere. Outside those niches the 500K context ceiling is the deciding constraint against it in long-document pipelines. Buy the data feed or buy the platform.
Verdicts are analysis, not measurement, and are labeled as such per our editorial policy.
FAQ
- Is Grok 4.5 cheaper than GPT-5.6 Terra?
- It depends on your token mix. Grok 4.5 bills $2 input / $6 output per million tokens; GPT-5.6 Terra bills $2 / $12 (as of August 11, 2026). Output-heavy workloads change the ranking.
- Which has the longer context window — Grok 4.5 or GPT-5.6 Terra?
- GPT-5.6 Terra does — 1M tokens against 512K for Grok 4.5.
- Which is the more capable model, Grok 4.5 or GPT-5.6 Terra?
- GPT-5.6 Terra scores higher on the Artificial Analysis Intelligence Index: 57 (measured August 11, 2026) against 56 for Grok 4.5 (measured August 11, 2026).
Comparison published August 11, 2026; underlying data last changed August 11, 2026.