Gemini 3.8 Flash vs Claude Opus 5
Claude Opus 5 was superseded by Claude Opus 5.5. 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 leads overall, C to C-. Claude Opus 5 is about 2.4x cheaper per task. By suite, real-world issues is even at C- and Claude Opus 5 takes spec planning (C to D+). The data gives no reason to pick Gemini 3.8 Flash over Claude Opus 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: Claude Opus 5 vs Gemini 3.8 Flash
Claude Opus 5 leads overall, C to C-. By suite: real-world issues is even at C- (60% vs 57% capability); Claude Opus 5 takes spec planning, C to D+ (66% vs 50% capability); Claude Opus 5 takes vibe coding, C+ to C- (72% vs 56% capability). Gemini 3.8 Flash used 23.7% of Google AI Pro's weekly limit per pass, $0.057 per task at the listed price. Claude Opus 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task, Claude Opus 5 is about 2.4x cheaper ($0.024 vs $0.057). Claude Opus 5 is faster on real-world issues: a median task takes 1m 56s against 5m 21s. Both finished every task on it. The data gives no reason to pick Gemini 3.8 Flash over Claude Opus 5 this week.
Changed since the previous graded week: Gemini 3.8 Flash: real-world issues F to C-, real-world issues usage 18.0% to 21.9% of the weekly limit, spec planning usage 2.0% to 1.8% of the weekly limit, vibe coding D+ to C-, vibe coding usage 1.2% to 1.1% of the weekly limit; Claude Opus 5: real-world issues usage 3% to 1% of the weekly limit.
| Dimension | Gemini 3.8 Flash | Claude Opus 5 | Advantage |
|---|---|---|---|
| Capability | 60% | 57% | +3% (Gemini 3.8 Flash leads) |
| Median task time | 5m 21s | 1m 56s | 3m 25s faster (Claude Opus 5 leads) |
| Approx. task cost | $0.067 / task | $0.015 / task | $0.052 / task lower (Claude Opus 5 leads) |
Gemini 3.8 Flash: 21.9% of Google AI Pro (131.3% / 5h, 21.9% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. Claude Opus 5: 21.0% of Claude Max 5x (21.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.8 Flash | Claude Opus 5 | Advantage |
|---|---|---|---|
| Capability | 50% | 66% | +15% (Claude Opus 5 leads) |
| Median task time | 3m 0s | 2m 9s | 52s faster (Claude Opus 5 leads) |
| Approx. task cost | $0.021 / task | $0.057 / task | $0.036 / task lower (Gemini 3.8 Flash leads) |
Gemini 3.8 Flash: 1.8% of Google AI Pro (11.0% / 5h, 1.8% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. Claude Opus 5: 6.0% of Claude Max 5x (6.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.8 Flash | Claude Opus 5 | Advantage |
|---|---|---|---|
| Capability | 56% | 72% | +15% (Claude Opus 5 leads) |
| Median task time | 7m 51s | 2m 51s | 4m 59s faster (Claude Opus 5 leads) |
| Approx. task cost | $0.048 / task | $0.011 / task | $0.037 / task lower (Claude Opus 5 leads) |
Gemini 3.8 Flash: 1.1% of Google AI Pro (6.3% / 5h, 1.1% / 1w) per good solve. Its weekly limit holds 6 of the week's 33.6 5h windows. Claude Opus 5: 1.6% of Claude Max 5x (1.6% / 5h) per good solve. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. 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, Gemini 3.8 Flash or Claude Opus 5?
Gemini 3.8 Flash clears higher: tier 4 of 5 versus tier 2 for Claude Opus 5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-27.
Which is cheaper per task, Gemini 3.8 Flash or Claude Opus 5?
Gemini 3.8 Flash used 23.7% of Google AI Pro's weekly limit per pass, $0.057 per task at the listed price. Claude Opus 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task, Claude Opus 5 is about 2.4x cheaper ($0.024 vs $0.057).