GPT-5.1 vs Grok 4.5
Benchmark Performance
Available Benchmarks
| Benchmark | GPT-5.1 | Grok 4.5 |
|---|---|---|
| ARC-AGI-1verified-v1-15fb467fd4fc · verified_score · leader | 72.8384% of row best · percent · GPT-5.1 (Thinking, High) | 87.17100% of row best · percent · Grok 4.5 (Medium) |
| ARC-AGI-2verified-v2-9a3db289984e · verified_score · leader | 17.6434% of row best · percent · GPT-5.1 (Thinking, High) | 52.64100% of row best · percent · Grok 4.5 (Medium) |
| LMArena Document Arenadocument-2026-07-30-011508720696 · arena_rating · leader | 1,400.8496% of row best · rating · gpt-5.1; 95% CI [1391.40144375, 1410.27736947]; votes 8220; rank 37 | 1,453.73100% of row best · rating · grok-4.5; 95% CI [1441.93744334, 1465.52785378]; votes 2435; rank 20 |
| LMArena Search Arenasearch-2026-08-24-011508720696 · arena_rating · leader | 1,199.4499% of row best · rating · gpt-5.1-search; 95% CI [1194.20592738, 1204.68165473]; votes 59909; rank 14 | 1,212.65100% of row best · rating · grok-4.5; 95% CI [1205.78347274, 1219.50889748]; votes 31505; rank 8 |
| LMArena Text Arenatext-2026-09-01-011508720696 · arena_rating · leader | 1,422.4798% of row best · rating · gpt-5.1; 95% CI [1418.85253526, 1426.08681113]; votes 43002; rank 96 | 1,451.82100% of row best · rating · grok-4.5; 95% CI [1446.90989155, 1456.73122428]; votes 25873; rank 39 |
| LMArena Vision Arenavision-2026-08-27-011508720696 · arena_rating · leader | 1,235.1996% of row best · rating · gpt-5.1; 95% CI [1227.44529223, 1242.93837299]; votes 10223; rank 60 | 1,291.11100% of row best · rating · grok-4.5; 95% CI [1282.25469345, 1299.96666150]; votes 6401; rank 22 |
| ToneBench2026-08-28-10-task-cd9819ab6e4d · overall_score · leader | 75.9892% of row best · points · GPT-5.1 · 3,970 output tokens / case | 82.23100% of row best · points · Grok 4.5 · 2,688 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 0 benchmark wins | 7 benchmark winsOverall lead |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | GPT-5.1 | Grok 4.5 |
|---|---|---|
| Developer | Openai | Xai |
| Family | Gpt 5 1 | Grok 4 |
| Model | GPT-5.1 | Grok 4.5 |
| Version | GPT-5.1 | Grok 4.5 |
| Lifecycle | active | active |
| Released | 2025-11-13 | 2026-07-16 |
| Knowledge cutoff | 2024-09-30 | Unknown |
| Input modalities | Unknown | Unknown |
| Output modalities | Unknown | Unknown |
| Context window | 400,000 | 500,000 |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Openai (Standard), Openrouter (Standard) | Xai (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
12 comparable fields · 7 material differences · Interactive comparison only; indexing gate not met
GPT-5.1 Capabilities
Grok 4.5 Capabilities
Primary Evidence
Sources and Freshness
Questions
GPT-5.1 vs Grok 4.5 FAQs
Is GPT-5.1 or Grok 4.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5.1 and Grok 4.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5.1 or Grok 4.5?+
Only GPT-5.1 has a directly sourced input price: $1.25 per million tokens. Only GPT-5.1 has a directly sourced output price: $10.00 per million tokens.
Which has a larger context window, GPT-5.1 or Grok 4.5?+
Grok 4.5 has the larger sourced context window. GPT-5.1 supports 400,000 and Grok 4.5 supports 500,000.
Which performs better in benchmarks, GPT-5.1 or Grok 4.5?+
Grok 4.5 leads the current overall benchmark count. The result uses 7 protocol-matched benchmarks from 3 publishers; it is not a universal quality score.
Can GPT-5.1 or Grok 4.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-5.1 is not marked open weight; Grok 4.5 is not marked open weight.
Can GPT-5.1 and Grok 4.5 understand images?+
GPT-5.1 is not documented with image input; Grok 4.5 is not documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5.1 or Grok 4.5?+
Neither has a larger sourced maximum output. GPT-5.1 is 128,000 and Grok 4.5 is —.
Do GPT-5.1 and Grok 4.5 support reasoning and tool use?+
GPT-5.1: reasoning and tool calling. Grok 4.5: reasoning and tool calling. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5.1 or Grok 4.5?+
GPT-5.1 has 2 sourced provider routes; Grok 4.5 has 1, so GPT-5.1 has broader tracked availability.
Which offers better value, GPT-5.1 or Grok 4.5?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.