GPT-6 Luna vs Grok 4.6
Grok 4.6 leads overall, C- to D. GPT-6 Luna is about 65x cheaper per task. By suite, GPT-6 Luna takes real-world issues (D+ to D) and Grok 4.6 takes spec planning (C to C-). Take GPT-6 Luna anyway when you want the side that is cheaper per task, faster on real-world issues and ahead on real-world issues.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 4.6 vs GPT-6 Luna
Grok 4.6 leads overall, C- to D. By suite: GPT-6 Luna takes real-world issues, D+ to D (50% vs 47% capability); Grok 4.6 takes spec planning, C to C- (66% vs 61% capability); Grok 4.6 takes vibe coding, C- to F (61% vs 33% capability). GPT-6 Luna used 1% of ChatGPT Plus's weekly limit per pass, $0.002 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~0.2% of ChatGPT Pro 5x's weekly limit (est, about $0.002 per task). Grok 4.6 used 13% of SuperGrok Plus's weekly limit per pass, $0.157 per task at the listed price. Per task, GPT-6 Luna is about 65x cheaper ($0.002 vs $0.157). GPT-6 Luna is faster on real-world issues: a median task takes 1m 0s against 7m 10s. Both finished every task on it. Reasons to pick GPT-6 Luna anyway: it is cheaper per task ($0.002 vs $0.157), it is faster on real-world issues (1m 0s vs 7m 10s median) and it leads on real-world issues (D+ to D).
Changed since W38: Grok 4.6: real-world issues C- to D, real-world issues usage 4% to 3% of the weekly limit, vibe coding C+ to C-.
| Dimension | GPT-6 Luna | Grok 4.6 | Advantage |
|---|---|---|---|
| Capability | 50% | 47% | +3% (GPT-6 Luna leads) |
| Median task time | 1m 0s | 7m 10s | 6m 10s faster (GPT-6 Luna leads) |
| Approx. task cost | $0.003 / task | $0.046 / task | $0.043 / task lower (GPT-6 Luna leads) |
GPT-6 Luna: 1.0% of ChatGPT Plus (1.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Grok 4.6: 3.0% of SuperGrok Plus (3.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Luna | Grok 4.6 | Advantage |
|---|---|---|---|
| Capability | 61% | 66% | +5% (Grok 4.6 leads) |
| Median task time | 1m 8s | 45m 26s | 44m 18s faster (GPT-6 Luna leads) |
| Approx. task cost | <$0.011 / task | $0.575 / task | $0.563 / task lower (GPT-6 Luna leads) |
GPT-6 Luna: under 1% of ChatGPT Plus per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Grok 4.6: 10.0% of SuperGrok Plus (10.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Luna | Grok 4.6 | Advantage |
|---|---|---|---|
| Capability | 33% | 61% | +28% (Grok 4.6 leads) |
| Median task time | 1m 37s | 11m 14s | 9m 37s faster (GPT-6 Luna leads) |
| Approx. task cost | not measured | <$0.230 / task | - |
GPT-6 Luna: under 1% of ChatGPT Plus (0.4% / 5h) per good solve. Its weekly limit holds about 6 of the week's 33.6 5h windows. Grok 4.6: under 1% of SuperGrok Plus 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, GPT-6 Luna or Grok 4.6?
Grok 4.6 clears higher: tier 4 of 5 versus tier 2 for GPT-6 Luna on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-23.
Which is cheaper per task, GPT-6 Luna or Grok 4.6?
GPT-6 Luna used 1% of ChatGPT Plus's weekly limit per pass, $0.002 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~0.2% of ChatGPT Pro 5x's weekly limit (est, about $0.002 per task). Grok 4.6 used 13% of SuperGrok Plus's weekly limit per pass, $0.157 per task at the listed price. Per task, GPT-6 Luna is about 65x cheaper ($0.002 vs $0.157).
What do GPT-6 Luna and Grok 4.6 cost a month?
GPT-6 Luna runs on ChatGPT Plus at $20/month (public price as of 2026-07-20). Grok 4.6 runs on SuperGrok Plus at $100/month (public price as of 2026-09-14).