Gemini 3.8 Flash vs Claude Sonnet 5
Claude Sonnet 5 is no longer on the leaderboard. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
Gemini 3.8 Flash leads overall, C- to D. Claude Sonnet 5 is about 2.4x cheaper per task. By suite, Gemini 3.8 Flash takes real-world issues (C- to D+) and spec planning (D+ to D). Take Claude Sonnet 5 anyway when you want the side that is cheaper per task and faster 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: Claude Sonnet 5 vs Gemini 3.8 Flash
Gemini 3.8 Flash leads overall, C- to D. By suite: Gemini 3.8 Flash takes real-world issues, C- to D+ (60% vs 53% capability); Gemini 3.8 Flash takes spec planning, D+ to D (50% vs 44% capability); Gemini 3.8 Flash takes vibe coding, C- to F (56% vs 31% 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 Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task, Claude Sonnet 5 is about 2.4x cheaper ($0.024 vs $0.057). Claude Sonnet 5 is faster on real-world issues: a median task takes 3m 35s against 5m 21s. Both finished every task on it. Reasons to pick Claude Sonnet 5 anyway: it is cheaper per task ($0.024 vs $0.057) and it is faster on real-world issues (3m 35s vs 5m 21s median).
Changed since W39: 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 Sonnet 5: vibe coding D+ to F.
| Dimension | Gemini 3.8 Flash | Claude Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 60% | 53% | +7% (Gemini 3.8 Flash leads) |
| Median task time | 5m 21s | 3m 35s | 1m 45s faster (Claude Sonnet 5 leads) |
| Approx. task cost | $0.067 / task | $0.015 / task | $0.052 / task lower (Claude Sonnet 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 Sonnet 5: 12.0% of Claude Max 5x (12.0% / 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 Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 50% | 44% | +7% (Gemini 3.8 Flash leads) |
| Median task time | 3m 0s | 5m 12s | 2m 11s faster (Gemini 3.8 Flash 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 Sonnet 5: 5.0% of Claude Max 5x (5.0% / 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 Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 56% | 31% | +25% (Gemini 3.8 Flash leads) |
| Median task time | 7m 51s | 4m 31s | 3m 20s faster (Claude Sonnet 5 leads) |
| Approx. task cost | $0.048 / task | $0.007 / task | $0.042 / task lower (Claude Sonnet 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 Sonnet 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. 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 Sonnet 5?
Gemini 3.8 Flash clears higher: tier 4 of 5 versus tier 3 for Claude Sonnet 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 Sonnet 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 Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task, Claude Sonnet 5 is about 2.4x cheaper ($0.024 vs $0.057).