Claude Opus 5.5 vs Grok 4.5
Grok 4.5 was superseded by Grok 4.7. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
Claude Opus 5.5 leads overall, B- to C-. Claude Opus 5.5 is about 1.3x cheaper per task. By suite, Claude Opus 5.5 takes real-world issues (C+ to C-) and vibe coding (B+ to C-). The data gives no reason to pick Grok 4.5 over Claude Opus 5.5 this week.Measured
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
Verdict: Grok 4.5 vs Claude Opus 5.5
Claude Opus 5.5 leads overall, B- to C-. By suite: Claude Opus 5.5 takes real-world issues, C+ to C- (73% vs 60% capability); Claude Opus 5.5 takes vibe coding, B+ to C- (90% vs 59% capability). Only Claude Opus 5.5 has run spec planning. Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Grok 4.5 used 6.9% of SuperGrok's weekly limit per pass, $0.032 per task at the listed price. Per task, Claude Opus 5.5 is about 1.3x cheaper ($0.024 vs $0.032). Claude Opus 5.5 is faster on real-world issues: a median task takes 1m 17s against 3m 9s. Both finished every task on it. The data gives no reason to pick Grok 4.5 over Claude Opus 5.5 this week.
Changed since the previous graded week: Claude Opus 5.5: real-world issues C- to C+, vibe coding B to B+; Grok 4.5: real-world issues usage 8.0% to 6.9% of the weekly limit.
| Dimension | Claude Opus 5.5 | Grok 4.5 | Advantage |
|---|---|---|---|
| Capability | 73% | 60% | +13% (Claude Opus 5.5 leads) |
| Median task time | 1m 17s | 3m 9s | 1m 53s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.032 / task | $0.016 / task lower (Claude Opus 5.5 leads) |
Claude Opus 5.5: 11.0% of Claude Max 5x (11.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Grok 4.5: 6.9% of SuperGrok (6.9% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Only Claude Opus 5.5 has run this suite, so there is no head-to-head yet.
| Dimension | Claude Opus 5.5 | Grok 4.5 | Advantage |
|---|---|---|---|
| Capability | 90% | 59% | +31% (Claude Opus 5.5 leads) |
| Median task time | 2m 44s | 3m 40s | 55s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.031 / task | $0.024 / task lower (Claude Opus 5.5 leads) |
Claude Opus 5.5: 1.0% of Claude Max 5x (1.0% / 5h) per good solve. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Grok 4.5: 0.4% of SuperGrok (0.4% / 1w) per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, Claude Opus 5.5 or Grok 4.5?
Both clear tier 4 of 5, but Claude Opus 5.5 scores higher on capability: 73% versus 60% on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Claude Opus 5.5 or Grok 4.5?
Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Grok 4.5 used 6.9% of SuperGrok's weekly limit per pass, $0.032 per task at the listed price. Per task, Claude Opus 5.5 is about 1.3x cheaper ($0.024 vs $0.032).
What do Claude Opus 5.5 and Grok 4.5 cost a month?
Claude Opus 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). Grok 4.5 runs on SuperGrok at $30/month (public price as of 2026-07-20).