Claude Opus 4.8 vs Grok 4.5
At a Glance
| Compare | Claude Opus 4.8Anthropic | Grok 4.5xAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | #18 of 4670.1 score · 3/3 sources · complete | #25 of 4660.1 score · 3/3 sources · complete |
| CostLower is better · Published-token output estimate | #42 of 44$0.604 per LiveBench case | #15 of 44$0.063 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.5 | #35 of 3840.5 score · 3/3 sources · complete | #11 of 3859.2 score · 3/3 sources · complete |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $5.00Anthropic ↗ · Sep 3, 2026 | $2.00Xai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $25.00Anthropic ↗ · Sep 3, 2026 | $6.00Xai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 1,000K | 500K |
| Model facts checked | Aug 29, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | Claude Opus 4.8 | Grok 4.5 |
|---|---|---|
| ARC-AGI-1verified-v1-ba05d69f6453 · verified_score · leader | 92.50100% of row best · percent · Claude Opus 4.8 (Max) | 87.1794% of row best · percent · Grok 4.5 (Medium) |
| ARC-AGI-2verified-v2-6c676fa3e9af · verified_score · leader | 72.08100% of row best · percent · Claude Opus 4.8 (High) | 52.6473% of row best · percent · Grok 4.5 (Medium) |
| LMArena Agent Arenaagent-2026-09-15-d25aabda0010 · outcome_score · leader | 8.19100% of row best · score · Claude Opus 4.8 (High); 95% CI [6.91963673, 9.45737628]; sessions 39731; observations 2097389; rank 6 | 2.9295% of row best · score · Grok 4.5; 95% CI [1.93207740, 3.90928463]; sessions 38146; observations 1942877; rank 19 |
| LMArena Document Arenadocument-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,464.07100% of row best · rating · claude-opus-4-8; 95% CI [1457.10320334, 1471.03216030]; votes 12128; rank 19 | 1,451.9699% of row best · rating · grok-4.5; 95% CI [1443.26182849, 1460.65626012]; votes 4965; rank 26 |
| LMArena Search Arenasearch-2026-08-24-d25aabda0010 · arena_rating · statistical tie | 1,204.3099% of row best · rating · claude-opus-4-8; 95% CI [1197.89112684, 1210.71069451]; votes 70998; rank 12 | 1,212.65100% of row best · rating · grok-4.5; 95% CI [1205.78347274, 1219.50889748]; votes 31505; rank 8 |
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,452.66100% of row best · rating · claude-opus-4-8; 95% CI [1448.52490690, 1456.79817098]; votes 53446; rank 40 | 1,450.13100% of row best · rating · grok-4.5; 95% CI [1445.44268767, 1454.81726995]; votes 30103; rank 45 |
| LMArena Vision Arenavision-2026-09-13-d25aabda0010 · arena_rating · statistical tie | 1,288.23100% of row best · rating · claude-opus-4-8; 95% CI [1281.27991800, 1295.18871241]; votes 15801; rank 25 | 1,288.54100% of row best · rating · grok-4.5; 95% CI [1280.47745270, 1296.60872281]; votes 8355; rank 24 |
| LiveBench2026-06-25 · overall · leader | 81.18100% of row best · percent · claude-opus-4-8-max-effort · 24,171 output tokens / case | 80.0199% of row best · percent · grok-4.5 · 10,517 output tokens / case |
| ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified | 87.91100% of row best · points · Claude Opus 4.8 (max effort) · 24,846 output tokens / case | 82.2394% of row best · points · Grok 4.5 · 2,688 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above · 4 ties | 4 benchmark winsOverall lead | 0 benchmark wins |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Side-by-Side Facts
| Field | Claude Opus 4.8 | Grok 4.5 |
|---|---|---|
| Developer | Anthropic | xAI |
| Family | Claude 4 8 | Grok 4 |
| Model | Claude Opus 4.8 | Grok 4.5 |
| Version | Claude Opus 4.8 | Grok 4.5 |
| Lifecycle | active | active |
| Released | 2026-05-28 | 2026-07-16 |
| Knowledge cutoff | 2026-01-01 | Unknown |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 500K |
| 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 | Anthropic (Standard), Deepinfra (Standard) | Xai (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
Claude Opus 4.8 Capabilities
Grok 4.5 Capabilities
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Primary Evidence
Sources and Freshness
Questions
Claude Opus 4.8 vs Grok 4.5 FAQs
Is Claude Opus 4.8 or Grok 4.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Opus 4.8 and Grok 4.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Opus 4.8 or Grok 4.5?+
Claude Opus 4.8 is $5.00 and Grok 4.5 is $2.00 per million tokens, so Grok 4.5 is cheaper on this metric. Claude Opus 4.8 is $25.00 and Grok 4.5 is $6.00 per million tokens, so Grok 4.5 is cheaper on this metric.
Which has a larger context window, Claude Opus 4.8 or Grok 4.5?+
Claude Opus 4.8 has the larger sourced context window. Claude Opus 4.8 supports 1,000K and Grok 4.5 supports 500K.
Which performs better in benchmarks, Claude Opus 4.8 or Grok 4.5?+
Claude Opus 4.8 leads the current overall benchmark count. The result uses 8 protocol-matched benchmarks from 3 publishers; it is not a universal quality score.
Can Claude Opus 4.8 or Grok 4.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Opus 4.8 is not marked open weight; Grok 4.5 is not marked open weight.
Can Claude Opus 4.8 and Grok 4.5 understand images?+
Claude Opus 4.8 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, Claude Opus 4.8 or Grok 4.5?+
Neither has a larger sourced maximum output. Claude Opus 4.8 is 128K and Grok 4.5 is —.
Do Claude Opus 4.8 and Grok 4.5 support reasoning and tool use?+
Claude Opus 4.8: 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, Claude Opus 4.8 or Grok 4.5?+
Claude Opus 4.8 has 2 sourced provider routes; Grok 4.5 has 1, so Claude Opus 4.8 has broader tracked availability.
Which offers better value, Claude Opus 4.8 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.