Model comparison
Claude Opus 5 vs Gemini 3.8 Flash
Anthropic against Google, compared on context, price, and verified benchmark results.
Catalog record checked September 3, 2026Individual provider fields may changeEvidence confidence: High — see receipts below
Anthropic
Claude Opus 5
Frontier
Gemini 3.8 Flash
Balanced
| Specification | Claude Opus 5 | Gemini 3.8 Flash |
|---|---|---|
| Provider | Anthropic | |
| Tier | Frontier | Balanced |
| Context window | 1M | Winner: 1.05M |
| Max output | Winner: 128K | 66K |
| Input / 1M tokens | $5 | Winner: $0.75 |
| Output / 1M tokens | $25 | Winner: $3.75 |
| Weights | Closed | Closed |
| Parameters | Not disclosedUnverified | Not disclosedUnverified |
| Reasoning levels | adaptive | low, medium, high |
| Modalities | text, image | text, image, video, audio, pdf |
| API model id | claude-opus-5 | gemini-3.8-flash |
| Released | July 24, 2026 | September 2, 2026 |
| Artificial Analysis Intelligence Index [max] (2026-08-14) | 63 | Not verifiedUnverified |
| Artificial Analysis Intelligence Index [high] (2026-09-02) | Not verifiedUnverified | 58.7 |
| Humanity's Last Exam (2026-09-01) | Winner: 63.6 | 54.9 |
| Terminal-Bench 2.1 (2026-09-03) | 86.7 | Winner: 89.4 |
Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.
Benchmark receipts
- 2026-09-03: Meta Muse Spark 1.3 launch table (independent cross-vendor run; conflicts with Google's 89.1 — both preserved)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
- 2026-09-02: Google official blog (vendor, HLE-Verified full set)Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise. Comparability: comparable with caveat — Subset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
- 2026-09-02: Google launch eval table (transcribed by Vellum)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
- 2026-09-02: Artificial AnalysisComposite index blending reasoning, knowledge, and coding evals into one 0–100 score. Comparability: directly comparable — AA occasionally rebaselines the index scale between snapshots — a score captured on one date is only comparable to same-snapshot scores (check measuredAt).
- 2026-09-01: Anthropic Fable 5.1 comparison table (vendor, with tools; 56.6 no tools)Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise. Comparability: comparable with caveat — Subset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
Pricing tiers: Claude Opus 5: Standard $5/$25 per MTok; cache reads 10% of base input. Knowledge cutoff May 2026. · Gemini 3.8 Flash: Intro $0.75/$3.75 per MTok through 2026-12-31, rising to $1.50/$7.50 from 2027-01-01; batch/Flex half price. Free tier available. Companion Gemini 3.8 Flash Cyber (defensive security) is restricted to the Fairwind Program with no public pricing.
Claude Opus 5
Claude Opus 5 is Anthropic's top model for complex agentic coding and enterprise work — superseded at the top of the Artificial Analysis Index by Fable 5.1 (2026-09-01) but stronger on price.
Best for
- Complex agentic coding
- Enterprise work
- Long-context analysis
Watch out
Output costs 5x input; long generations dominate the bill.
Gemini 3.8 Flash
Gemini 3.8 Flash is Google's most-intelligent workhorse Flash — tied for the top of DeepSWE 1.1 with Claude Opus 5 at roughly a fifth of the cost per task, three Flash releases in six weeks.
Best for
- Agentic coding at scale
- Mid-difficulty engineering
- Multimodal pipelines
Watch out
Intro pricing doubles on 2027-01-01, and Google says it can consume more tokens than 3.7 Flash — 3.7 Flash stays available for efficiency-first workloads.
Benchmark
DeepSWE 1.1 in context
Only Gemini 3.8 Flash has a published DeepSWE 1.1 result. It is shown against the wider field, with cost per completed task alongside the score.
Local leader
Gemini 3.8 Flash [high]
74%
Rows shown
27
Highest published reasoning effort per model (not best Pass@1)
Snapshot date
2026-09-03
Mirrored from deepswe.datacurve.ai
Better is toward the top-right (higher pass rate, lower cost). X-axis is reversed to match DeepSWE’s public chart. v1.1 uses average cost / tokens / steps; v1 uses published medians.
| # | Model | Pass@1 | Cost / task | Tokens / task | Steps / task |
|---|---|---|---|---|---|
| 1 | Gemini 3.8 Flash [high] | 74% | $2.36 | 143k | 166 |
| 2 | Claude Opus 5 [max] | 74% | $11.84 | 118k | 99 |
| 3 | GPT-5.6 Sol [max] | 73% | $8.39 | 60k | 61 |
| 4 | Claude Fable 5 [max] | 70% | $21.63 | 119k | 88 |
| 5 | GPT-5.6 Terra [max] | 70% | $4.95 | 72k | 76 |
| 6 | GLM 5.3 [max] | 69% | $3.99 | 80k | 124 |
| 7 | Kimi K3 [max] | 69% | $4.65 | 82k | 98 |
| 8 | GPT-5.6 Luna [max] | 67% | $3.03 | 73k | 102 |
| 9 | GPT-5.5 [xhigh] | 67% | $7.23 | 46k | 82 |
| 10 | Grok 4.6 [xhigh] | 67% | $5.50 | 71k | 87 |
| 11 | Gemini 3.7 Flash [high] | 65% | $2.18 | 107k | 125 |
| 12 | GLM 5.3 Flash [max] | 63% | $0.48 | 73k | 123 |
| 13 | DeepSeek V4-Pro [max] | 63% | $0.24 | 106k | 155 |
| 14 | Claude Opus 4.8 [max] | 59% | $13.22 | 135k | 120 |
| 15 | Qwen3.8-Max [xhigh] | 58% | $3.73 | 95k | 111 |
| 16 | Muse Spark 1.2 [xhigh] | 55% | $3.70 | 99k | 101 |
| 17 | Claude Sonnet 5 [max] | 54% | $26.40 | 214k | 268 |
| 18 | Grok 4.5 [high] | 54% | $2.42 | 36k | 61 |
| 19 | DeepSeek V4-Flash [max] | 53% | $0.10 | 108k | 153 |
| 20 | Muse Spark 1.1 [xhigh] | 53% | $2.36 | 74k | 96 |
| 21 | GPT-5.4 [xhigh] | 52% | $5.65 | 71k | 70 |
| 22 | Gemini 3.6 Flash [high] | 47% | $4.42 | 96k | 117 |
| 23 | GLM 5.2 [max] | 44% | $3.92 | 78k | 129 |
| 24 | Gemini 3.5 Flash [high] | 36% | $3.45 | 76k | 105 |
| 25 | Kimi K2.7 Code | 31% | $2.82 | 59k | 149 |
| 26 | Claude Sonnet 4.6 [high] | 30% | $5.52 | 76k | 134 |
| 27 | Gemini 3.1 Pro [high] | 12% | $2.14 | 28k | 76 |
DeepSWE “Best” picks the highest published reasoning effort per model (not the highest pass rate). Small gaps may not be statistically meaningful — confirm on deepswe.datacurve.ai.
When the cheaper one wins
Gemini 3.8 Flash is cheaper on output at $3.75 per million tokens against $25 for Claude Opus 5 — about 6.7×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.
Run the model pickerEvidence confidence: High
How strong and complete the evidence behind this comparison is — not a prediction of which model is better.
- Pricing verified on both sides — Input and output rates are verified for both models.
- 4/5 core specs verified on both sides — Not published for at least one side: parameter count.
- 4 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, Humanity's Last Exam, Terminal-Bench 2.1, Terminal-Bench 2.1.
- Verified within the last 90 days — Newest catalog check was 8 days ago.
- Both models carry source citations — Each side has at least two catalog sources on record.
Source receipts
Each catalog figure was checked against the provider or an independent second source on the date shown.
- Claude Opus 5: Anthropic — Claude Opus 5 (accessed 2026-08-29)
- Claude Opus 5: Anthropic news — Claude Opus 5 (accessed 2026-08-29)
- Gemini 3.8 Flash: Google — Gemini 3.8 Flash and 3.8 Flash Cyber (accessed 2026-09-03)
- Gemini 3.8 Flash: Gemini API pricing (gemini-3.8-flash $0.75/$3.75 intro) (accessed 2026-09-03)
- Gemini 3.8 Flash: DeepSWE 1.1 leaderboard — gemini-3.8-flash [high] 73.8% at $2.36/task (accessed 2026-09-03)
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Diving deeper on one model? Claude Opus 5 · Gemini 3.8 Flash
Common questions
Claude Opus 5 vs Gemini 3.8 Flash
Answered from the verified figures on this page rather than general guidance.
Is Claude Opus 5 or Gemini 3.8 Flash cheaper for input?
Gemini 3.8 Flash is cheaper at $0.75 per million input tokens, against $5 for Claude Opus 5 — roughly 6.7× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Claude Opus 5 has tiered pricing: Standard $5/$25 per MTok; cache reads 10% of base input. Knowledge cutoff May 2026. Gemini 3.8 Flash has tiered pricing: Intro $0.75/$3.75 per MTok through 2026-12-31, rising to $1.50/$7.50 from 2027-01-01; batch/Flex half price. Free tier available. Companion Gemini 3.8 Flash Cyber (defensive security) is restricted to the Fairwind Program with no public pricing.
Is Claude Opus 5 or Gemini 3.8 Flash cheaper for output?
Gemini 3.8 Flash is cheaper at $3.75 per million output tokens, against $25 for Claude Opus 5 — roughly 6.7× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Claude Opus 5 has tiered pricing: Standard $5/$25 per MTok; cache reads 10% of base input. Knowledge cutoff May 2026. Gemini 3.8 Flash has tiered pricing: Intro $0.75/$3.75 per MTok through 2026-12-31, rising to $1.50/$7.50 from 2027-01-01; batch/Flex half price. Free tier available. Companion Gemini 3.8 Flash Cyber (defensive security) is restricted to the Fairwind Program with no public pricing.
Which has the larger context window, Claude Opus 5 or Gemini 3.8 Flash?
Gemini 3.8 Flash accepts 1.05M tokens against 1M for Claude Opus 5. This only matters if you routinely send very long documents or large codebases.
Do Claude Opus 5 and Gemini 3.8 Flash support the same reasoning levels?
Claude Opus 5 exposes adaptive, while Gemini 3.8 Flash exposes low, medium, high.
Should I use Claude Opus 5 or Gemini 3.8 Flash?
Claude Opus 5 is the frontier tier and Gemini 3.8 Flash the balanced tier. The useful question is whether your hardest task actually fails on the cheaper one — most production volume such as classification, extraction and summarisation does not.
Next step
Choosing between them
The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.
- Input price: Gemini 3.8 Flash costs $0.75 per 1M tokens versus $5 for Claude Opus 5 — a 6.7x difference at the headline tier.
- Context: Gemini 3.8 Flash takes 1.05M against 1M for Claude Opus 5 — only decisive if your prompts approach the smaller window.
- Measured capability: Claude Opus 5 leads Artificial Analysis Intelligence Index 63 to 58.7 (measured 2026-08-14).
- Positioning: Claude Opus 5 sits in the frontier tier, Gemini 3.8 Flash in the balanced tier — most production volume (classification, extraction, summarisation) does not need the pricier tier.
Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.