Model comparison
Claude Opus 5 vs Gemini 3.8 Flash
Anthropic against Google, compared on context, price, and attributed benchmark results.
Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below
Anthropic
Claude Opus 5
Frontier
Gemini 3.8 Flash
Balanced
| Specification | Claude Opus 5 | Gemini 3.8 Flash |
|---|---|---|
| Provider | ||
| Provider | Anthropic | |
| Tier | ||
| Tier | Frontier | Balanced |
| Context window | ||
| Context window | 1M | Winner: 1.05M |
| Max output | ||
| Max output | Winner: 128K | 66K |
| Input / 1M tokens | ||
| Input / 1M tokens | $5 | Winner: $0.75 |
| Output / 1M tokens | ||
| Output / 1M tokens | $25 | Winner: $3.75 |
| Weights | ||
| Weights | Closed | Closed |
| Parameters | ||
| Parameters | Not verifiedUnverified | Not verifiedUnverified |
| Reasoning levels | ||
| Reasoning levels | low, medium, high, xhigh, max | low, medium, high |
| Modalities | ||
| Modalities | text, image | text, image, video, audio, pdf |
| API model id | ||
| API model id | claude-opus-5 | gemini-3.8-flash |
| Released | ||
| Released | July 24, 2026 | September 2, 2026 |
| Humanity's Last Exam · source date Claude Opus 5: 2026-09-01 | ||
| Humanity's Last Exam · source date Claude Opus 5: 2026-09-01 | 63.6 | Not verifiedUnverified |
| Terminal-Bench 2.1 · source date Claude Opus 5: 2026-09-02 | ||
| Terminal-Bench 2.1 · source date Claude Opus 5: 2026-09-02 | 89.1 | Not verifiedUnverified |
| Terminal-Bench 2.1 · source date Gemini 3.8 Flash: 2026-09-02 | ||
| Terminal-Bench 2.1 · source date Gemini 3.8 Flash: 2026-09-02 | Not verifiedUnverified | 89.4 |
| Artificial Analysis Intelligence Index [high] · source date Gemini 3.8 Flash: 2026-10-01 | ||
| Artificial Analysis Intelligence Index [high] · source date Gemini 3.8 Flash: 2026-10-01 | Not verifiedUnverified | 41 |
| HLE-Verified · source date Gemini 3.8 Flash: 2026-09-02 | ||
| HLE-Verified · source date Gemini 3.8 Flash: 2026-09-02 | Not verifiedUnverified | 54.9 |
Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.
Benchmark receipts
Where each score comes from, and how far it can be compared across models.
- Source date2026-10-01Artificial Analysis (Gemini 3.8 Flash (high))
Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.
Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check the cited source and its date.
- Source date2026-09-02Google official blog and methodology (vendor; full 1,811-item HLE-Verified set) (Full 1,811-item verified/revised set; differs from original HLE and AA text-only HLE)
Expert reasoning on the verified and revised Humanity's Last Exam question set.
UnknownA distinct question set from original HLE and Artificial Analysis's text-only HLE. Shared dataset and publisher alone do not establish matching model effort, tools, filtering and run configuration; no quality winner is inferred without that evidence.
- Source date2026-09-02Google primary evaluation table and methodology (vendor-reported) (Vendor evaluation; Terminus-2 harness; exact run date not published)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
- Source date2026-09-02Google Gemini 3.8 Flash evaluation table quoting public leaderboard / Artificial Analysis, Terminus 2; not a Google-run Opus evaluation (Cross-provider quotation; common effort and experiment date unverified)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
- Source date2026-09-01Anthropic 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.
Comparable with caveatSubset/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 with no long-context surcharge. Cache reads $0.50; 5-minute writes $6.25 and 1-hour writes $10. Batch $2.50/$12.50. First-party Fast research preview $10/$50, unavailable with Batch. US-only inference adds 10% where supported. Batch 300K output requires output-300k-2026-03-24; standard stays 128K. Knowledge cutoff May 2026; retirement not sooner than July 24, 2027.
Gemini 3.8 Flash: Intro Standard $0.75/$3.75 per MTok through December 31, 2026; $1.50/$7.50 from January 1, 2027. Output includes thinking tokens. Cached input $0.075, rising to $0.15; storage $0.50/MTok-hour, rising to $1. Batch/Flex input/output are $0.375/$1.875, rising to $0.75/$3.75. Priority $1.35/$6.75, rising to $2.70/$13.50. Grounding tools have separate charges and quotas; free-tier limits differ from paid.
Claude Opus 5
Claude Opus 5 is Anthropic's July 2026 agentic-coding model, now 'Active (legacy)'. Its successor Opus 5.5 has lower base input/output prices ($4/$20 vs $5/$25 per million tokens); performance depends on the workload and evaluation settings.
Best for
- Complex agentic coding
- Enterprise work
- Long-context analysis
Watch out
Active legacy, superseded by Opus 5.5. Test migration: Opus 5.5 makes adaptive thinking always on, rejects forced tool use and the older computer-use tool, and changes thinking-block/progress behavior. Partner cloud lifecycles and prices can differ.
Gemini 3.8 Flash
Gemini 3.8 Flash is Google's multimodal Flash model for long-horizon software engineering and agent workflows, with current introductory API pricing through December 31, 2026.
Best for
- Agentic coding at scale
- Mid-difficulty engineering
- Multimodal pipelines
Watch out
Intro rates and cache-storage prices double January 1, 2027. Google says 3.8 can use more tokens at higher effort; 3.7 remains supported for efficiency-first workloads. Minimal thinking errors. Computer use is Preview; native audio/image generation and Live API are unsupported. Restricted Flash Cyber is a separate endpoint with no public rate confirmed.
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
GPT-6 Astra [xhigh]
74.1%
Rows shown
28
Best source-matched Pass@1 per model
Snapshot date
2026-10-01
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, output tokens and steps. Legacy v1 transcriptions are excluded here until an exact primary receipt is retained.
| # | Model | Pass@1 | Cost / task | Tokens / task | Steps / task |
|---|---|---|---|---|---|
| 1 | GPT-6 Astra [xhigh] | 74.1% | $4.43 | 30k | 29 |
| 2 | Gemini 3.8 Flash [high] | 73.8% | $2.36 | 143k | 166 |
| 3 | Claude Opus 5 [max] | 73.6% | $11.84 | 118k | 99 |
| 4 | GPT-5.6 Sol [max] | 72.7% | $8.39 | 60k | 61 |
| 5 | Claude Fable 5 [xhigh] | 69.9% | $13.41 | 80k | 68 |
| 6 | GPT-5.6 Terra [max] | 69.6% | $4.95 | 72k | 76 |
| 7 | GLM 5.3 [max] | 69.0% | $3.99 | 80k | 124 |
| 8 | Kimi K3 [max] | 68.5% | $4.65 | 82k | 98 |
| 9 | Grok 4.6 [medium] | 67.5% | $3.45 | 50k | 70 |
| 10 | GPT-5.6 Luna [max] | 67.2% | $3.03 | 73k | 102 |
| 11 | GPT-5.5 [xhigh] | 67.0% | $7.23 | 46k | 82 |
| 12 | Gemini 3.7 Flash [medium] | 65.5% | $2.03 | 94k | 117 |
| 13 | GLM 5.3 Flash [max] | 63.4% | $0.48 | 73k | 123 |
| 14 | DeepSeek V4-Pro [max] | 62.8% | $0.24 | 106k | 155 |
| 15 | Claude Opus 4.8 [max] | 59.0% | $13.22 | 135k | 120 |
| 16 | Qwen3.8-Max [xhigh] | 57.5% | $3.73 | 95k | 111 |
| 17 | Muse Spark 1.2 [xhigh] | 54.9% | $3.70 | 99k | 101 |
| 18 | Claude Sonnet 5 [max] | 53.8% | $26.40 | 214k | 268 |
| 19 | Grok 4.5 [high] | 53.8% | $2.42 | 36k | 61 |
| 20 | DeepSeek V4-Flash [max] | 53.3% | $0.10 | 108k | 153 |
| 21 | Muse Spark 1.1 [xhigh] | 53.3% | $2.36 | 74k | 96 |
| 22 | GPT-5.4 [xhigh] | 51.8% | $5.65 | 71k | 70 |
| 23 | Gemini 3.6 Flash [high] | 46.7% | $4.42 | 96k | 117 |
| 24 | GLM 5.2 [max] | 43.8% | $3.92 | 78k | 129 |
| 25 | Gemini 3.5 Flash [high] | 36.1% | $3.45 | 76k | 105 |
| 26 | Kimi K2.7 Code | 30.5% | $2.82 | 59k | 149 |
| 27 | Claude Sonnet 4.6 [high] | 29.9% | $5.52 | 76k | 134 |
| 28 | Gemini 3.1 Pro [high] | 11.7% | $2.14 | 28k | 76 |
“Best per model” shows each model’s highest source-matched Pass@1 in this capture; switch to all effort levels to see every retained configuration. Efforts differ across models, so this view is not a comparison at matched effort. The source was generated September 22 and captured October 1. 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. On DeepSWE 1.1, Gemini 3.8 Flash is 73.8% Pass@1 at $2.36/task versus Claude Opus 5 at 73.6% / $11.84/task. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.
Run the model pickerEvidence confidence: Medium
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.
- No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
- Verified within the last 90 days — Older of the two catalog checks was 25 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: Claude model overview — whole-profile source check October 1 (accessed 2026-10-01)
- Claude Opus 5: Claude current API pricing, caching and inference geography (accessed 2026-10-01)
- Claude Opus 5: Anthropic — Claude Opus 5 (accessed 2026-08-29)
- Claude Opus 5: Anthropic news — Claude Opus 5 (accessed 2026-08-29)
- Claude Opus 5: Anthropic — Claude Opus 5.5 (Opus 5 successor) (accessed 2026-09-26)
- Claude Opus 5: Anthropic selectable effort levels (separate from adaptive thinking mode) (accessed 2026-10-01)
- Gemini 3.8 Flash: Google primary profile — whole-record source check October 1 (accessed 2026-10-01)
- Gemini 3.8 Flash: Gemini current API pricing and cache-storage tiers (accessed 2026-10-01)
- 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: Datacurve DeepSWE 1.1 — 3.8 Flash high 73.8%, $2.36/task; Google separately self-reports 73.7% (accessed 2026-09-03)
Related comparisons
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- Amazon Nova 2 Pro vs Gemini 3.8 Flash
- Base 1 vs Gemini 3.8 Flash
- Claude Fable 5.1 vs Claude Opus 5
- Claude Fable 5 vs Claude Opus 5
- Claude Haiku 4.5 vs Claude Opus 5
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?
Is Claude Opus 5 or Gemini 3.8 Flash cheaper for output?
Which has the larger context window, Claude Opus 5 or Gemini 3.8 Flash?
Do Claude Opus 5 and Gemini 3.8 Flash support the same reasoning levels?
Should I use Claude Opus 5 or Gemini 3.8 Flash?
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.
- Positioning: Claude Opus 5 sits in the frontier tier, Gemini 3.8 Flash in the balanced tier. Compare accuracy, reliability, latency, and cost on representative tasks before choosing.
Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.