GPT-5 vs Grok 4.5
Benchmark Performance
Available Benchmarks
| Benchmark | GPT-5 | Grok 4.5 |
|---|---|---|
| ARC-AGI-1verified-v1-b2e2a31b3d53 · verified_score · leader | 65.6775% of row best · percent · GPT-5 (High) | 87.17100% of row best · percent · Grok 4.5 (Medium) |
| ARC-AGI-2verified-v2-326661568d5f · verified_score · leader | 9.8619% of row best · percent · GPT-5 (High) | 52.64100% of row best · percent · Grok 4.5 (Medium) |
| LMArena Search Arenasearch-2026-08-24-011508720696 · arena_rating · leader | 1,132.7793% of row best · rating · gpt-5-search; 95% CI [1126.91788409, 1138.61733849]; votes 20781; rank 30 | 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 | 1,405.9697% of row best · rating · gpt-5-high; 95% CI [1401.51371519, 1410.40173213]; votes 31418; rank 132 | 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 | 1,209.1794% of row best · rating · gpt-5-high; 95% CI [1202.30024113, 1216.04249064]; votes 34389; rank 72 | 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 | 77.8295% of row best · points · GPT-5 · 5,896 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 | 6 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 | Grok 4.5 |
|---|---|---|
| Developer | OpenAI | xAI |
| Family | Gpt 5 | Grok 4 |
| Model | GPT-5 | Grok 4.5 |
| Version | GPT-5 | Grok 4.5 |
| Lifecycle | active | active |
| Released | 2025-08-07 | 2026-07-16 |
| Knowledge cutoff | 2024-09-30 | Unknown |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| 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 |
14 comparable fields · 7 material differences · Pair passes the primary-source comparison gate
GPT-5 Capabilities
Grok 4.5 Capabilities
Internal Comparison Graph
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Primary Evidence
Sources and Freshness
Questions
GPT-5 vs Grok 4.5 FAQs
Is GPT-5 or Grok 4.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5 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 or Grok 4.5?+
GPT-5 is $0.625 and Grok 4.5 is $2.00 per million tokens, so GPT-5 is cheaper on this metric. GPT-5 is $5.00 and Grok 4.5 is $6.00 per million tokens, so GPT-5 is cheaper on this metric.
Which has a larger context window, GPT-5 or Grok 4.5?+
Grok 4.5 has the larger sourced context window. GPT-5 supports 400,000 and Grok 4.5 supports 500,000.
Which performs better in benchmarks, GPT-5 or Grok 4.5?+
Grok 4.5 leads the current overall benchmark count. The result uses 6 protocol-matched benchmarks from 3 publishers; it is not a universal quality score.
Can GPT-5 or Grok 4.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-5 is not marked open weight; Grok 4.5 is not marked open weight.
Can GPT-5 and Grok 4.5 understand images?+
GPT-5 is documented with image input; Grok 4.5 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5 or Grok 4.5?+
Neither has a larger sourced maximum output. GPT-5 is 128,000 and Grok 4.5 is —.
Do GPT-5 and Grok 4.5 support reasoning and tool use?+
GPT-5: reasoning, tool calling, and image input. Grok 4.5: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5 or Grok 4.5?+
GPT-5 has 2 sourced provider routes; Grok 4.5 has 1, so GPT-5 has broader tracked availability.
Which offers better value, GPT-5 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.