GPT-5.6 Terra vs Grok 4.6
API pricing, context, and independently measured performance, side by side. GPT-5.6 Terra starts 50% cheaper on input than Grok 4.6 at list prices.
GPT-5.6 Terra
OpenAI · released Jul 9, 2026
Best input$1.00 / MTok
Best output$6.00 / MTok
Context1.05M
Providers7
Fastest measured2s° TTFT · 95 tok/s
VisionToolsReasoningStructured outputPrompt caching
Grok 4.6
xAI · released Aug 12, 2026
Best input$2.00 / MTok
Best output$6.00 / MTok
Context500K
Providers4
Fastest measured0.79s° TTFT · 65 tok/s
VisionToolsReasoningStructured outputPrompt caching
Cheapest providers, measuredUSD / MTOK
| MODEL | PROVIDER | INPUT | OUTPUT | TTFT | TPS | SMOKE |
|---|---|---|---|---|---|---|
| GPT-5.6 Terra |  OpenAI | $1.00 | $6.00 | 2s° | 95° tok/s | — |
| GPT-5.6 Terra |  Azure | $2.00 | $12.00 | 6.5s° | 31° tok/s | — |
| GPT-5.6 Terra |  Amazon Bedrock | $2.20 | $13.20 | — | — | — |
| Grok 4.6 |  xAI | $2.00 | $6.00 | 0.79s° | 65° tok/s | — |
TTFT/TPS: ModelIndex-measured medians (P50, trailing 72h) · chat10k profile (~10K in / 200 out) · ° = measured via OpenRouter routing (adds a hop) · SMOKE: of 5 programmatic capability probes passed · methodology v1.1 — full details on each model page