{"id":499,"date":"2026-08-25T06:33:26","date_gmt":"2026-08-25T06:33:26","guid":{"rendered":"https:\/\/i10x.ai\/blog\/?p=499"},"modified":"2026-08-25T06:33:27","modified_gmt":"2026-08-25T06:33:27","slug":"claude-opus-5-vs-gemini-3-1-pro","status":"publish","type":"post","link":"https:\/\/i10x.ai\/blog\/claude-opus-5-vs-gemini-3-1-pro","title":{"rendered":"Claude Opus 5 vs Gemini 3.1 Pro: Benchmarks, Price & Which to Pick (2026)"},"content":{"rendered":"\n
\n\n

Comparison \u00b7 August 2026<\/p>\n\n

\nClaude Opus 5 (Anthropic API) and Gemini 3.1 Pro Preview (Google API) are both ~1M-class flagships. The split is not the window. It is price, modalities, and voice. This guide covers published API rates, three workload costs, live writing and coding snippets, and a routing matrix. Keep both if you mix careful prose with audio\/video packs. Start in a\nmulti-model AI workspace<\/a>\nor on\ni10X<\/a>.\n<\/p>\n\n

\nQuick verdict<\/strong>\n

Pick Claude Opus 5 if:<\/strong> you want warmer-but-still-operational email, deeper bug-review writeups, and a geology-grade refuse on false premises.<\/p>\n

Pick Gemini 3.1 Pro if:<\/strong> you need native audio and video input, cheaper Pro-class rates ($2\/$12 vs $5\/$25), cheaper cache, or Google-ecosystem fit at a similar ~1M window.<\/p>\n

Best default for many teams:<\/strong> Gemini for multimodal volume. Opus for critique and careful prose. Do not pay Opus rates for every video-adjacent job.<\/p>\n

Data checked: 2026-08-24. Prices and model cards change. Verify live API test and vendor pages.<\/em><\/p>\n<\/div>\n\n

\n\n\n\n\n\n\n

1M<\/strong><\/p><\/td>\n

Claude Opus 5 context (API)<\/p><\/td>\n<\/tr>\n

1.05M<\/strong><\/p><\/td>\n

Gemini 3.1 Pro Preview context (API)<\/p><\/td>\n<\/tr>\n

$5 \/ $25<\/strong><\/p><\/td>\n

Claude Opus 5 input\/output per 1M tokens (API pricing, 2026-08-24)<\/p><\/td>\n<\/tr>\n

$2 \/ $12<\/strong><\/p><\/td>\n

Gemini 3.1 Pro Preview input\/output per 1M tokens (API pricing, 2026-08-24)<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n

\n\"Bar\n
Figure 1.<\/strong> Where each model wins on relative axes (context, multimodal breadth, API cost efficiency, writing tightness vs filler, coding micro-test). Higher is stronger for that axis. Chart: i10X.<\/figcaption>\n<\/figure>\n\n
\n\n

Persona picker<\/h2>\n\n\n\n\n\n\n\n

You are\u2026<\/p><\/th>\n

Start with<\/p><\/th>\n

Why<\/p><\/th>\n<\/tr>\n

Writer \/ marketer<\/p><\/td>\n

Claude Opus 5 (often)<\/p><\/td>\n

Both ran warm. Gemini added extra \u201chope you are having a great week\u201d filler. Opus stayed more operational. Both captures truncated before the letter finished.<\/p><\/td>\n<\/tr>\n

Developer \/ agent builder<\/p><\/td>\n

Gemini default on cost. Opus for deep review.<\/p><\/td>\n

Empty-list bug was a tie. Gemini is much cheaper to loop. Opus wrote a fuller crash path.<\/p><\/td>\n<\/tr>\n

Researcher \/ analyst<\/p><\/td>\n

Gemini 3.1 Pro if media is in the pack<\/p><\/td>\n

Similar ~1M windows. Gemini\u2019s card adds audio and video. Opus is text\/image\/file.<\/p><\/td>\n<\/tr>\n

Budget \/ high volume<\/p><\/td>\n

Gemini 3.1 Pro<\/p><\/td>\n

Chat $0.008 vs $0.0175. Repo $0.208 vs $0.50. Cached agent $0.46 vs $1.05.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n

\n\n

What we are comparing (exact versions)<\/h2>\n

This page is Claude Opus 5 versus Gemini 3.1 Pro Preview, not Claude vs the Gemini app, and not an older Gemini 3 Pro ID. Nearby Gemini pages:\nGrok 4.6 vs Gemini 3.1 Pro<\/a>,\nGPT-5.5 vs Gemini 3.1 Pro<\/a>,\nGPT-5.6 Sol vs Gemini 3.1 Pro<\/a>.<\/p>\n\n\n\n\n\n\n\n\n

Field<\/p><\/th>\n

Claude Opus 5<\/p><\/th>\n

Gemini 3.1 Pro<\/p><\/th>\n<\/tr>\n

Provider<\/p><\/td>\n

Anthropic<\/p><\/td>\n

Google<\/p><\/td>\n<\/tr>\n

API model<\/p><\/td>\n

Claude Opus 5 (Anthropic API)<\/code><\/p><\/td>\n

Gemini 3.1 Pro Preview (Google API)<\/code><\/p><\/td>\n<\/tr>\n

Listed card name<\/p><\/td>\n

Claude Opus 5<\/p><\/td>\n

Google: Gemini 3.1 Pro Preview<\/p><\/td>\n<\/tr>\n

Family \/ tier<\/p><\/td>\n

Anthropic Opus flagship<\/p><\/td>\n

Gemini Pro-class preview<\/p><\/td>\n<\/tr>\n

App vs API note<\/p><\/td>\n

Also in Claude.ai \/ Anthropic apps. This article uses the API model.<\/p><\/td>\n

Also in Gemini app \/ Google AI Pro. This article uses the API preview model.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Preview IDs move. Re-check the live card before you freeze a router. For routing across many models, see\nAI model routing<\/a>.<\/p>\n\n

\n\n

Spec sheet (API card, 2026-08-24)<\/h2>\n\n\n\n\n\n\n\n\n

Spec<\/p><\/th>\n

Claude Opus 5<\/p><\/th>\n

Gemini 3.1 Pro Preview<\/p><\/th>\n<\/tr>\n

Context window<\/p><\/td>\n

1,000,000 tokens<\/p><\/td>\n

1,048,576 tokens<\/p><\/td>\n<\/tr>\n

Input modalities (card)<\/p><\/td>\n

text, image, file<\/p><\/td>\n

text, image, file, audio, video<\/p><\/td>\n<\/tr>\n

Output<\/p><\/td>\n

text<\/p><\/td>\n

text<\/p><\/td>\n<\/tr>\n

Open weights<\/p><\/td>\n

No<\/p><\/td>\n

No<\/p><\/td>\n<\/tr>\n

Vendor positioning (card)<\/p><\/td>\n

Flagship for demanding reasoning, coding, long-horizon agents. Strong at end-to-end software, code review, bug finding, visual analysis.<\/p><\/td>\n

Frontier reasoning. Enhanced software engineering, agentic reliability, efficient token use, multimodal foundation.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

We did not invent max-output or reasoning-effort rows. Confirm those on live vendor pages. The modality gap is the structural story: Gemini lists audio and video. Opus does not on this card.<\/p>\n\n

\n\n

Pricing and real workload cost<\/h2>\n

Rates as of 2026-08-24<\/strong>. Verify live<\/strong> before you budget.<\/p>\n\n\n\n\n\n\n

Price<\/p><\/th>\n

Claude Opus 5<\/p><\/th>\n

Gemini 3.1 Pro Preview<\/p><\/th>\n<\/tr>\n

Input \/ 1M tokens<\/p><\/td>\n

$5.00<\/p><\/td>\n

$2.00<\/p><\/td>\n<\/tr>\n

Output \/ 1M tokens<\/p><\/td>\n

$25.00<\/p><\/td>\n

$12.00<\/p><\/td>\n<\/tr>\n

Cache read \/ 1M<\/p><\/td>\n

$0.50<\/p><\/td>\n

$0.20<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Gemini is cheaper on input, output, and cache. Opus is the premium review model in this pairing.<\/p>\n\n\n\n\n\n\n

Scenario<\/p><\/th>\n

Assumed tokens<\/p><\/th>\n

Est. Claude Opus 5<\/p><\/th>\n

Est. Gemini 3.1 Pro<\/p><\/th>\n<\/tr>\n

Chat turn<\/p><\/td>\n

1k in + 0.5k out<\/p><\/td>\n

$0.0175<\/p><\/td>\n

$0.008<\/p><\/td>\n<\/tr>\n

Repo \/ doc review<\/p><\/td>\n

80k in + 4k out<\/p><\/td>\n

$0.500<\/p><\/td>\n

$0.208<\/p><\/td>\n<\/tr>\n

Agent loop<\/p><\/td>\n

200k in (50% cached) + 20k out<\/p><\/td>\n

$1.050<\/p><\/td>\n

$0.460<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\n\"Bar\n
Figure 2.<\/strong> Estimated USD per run using published API list rates (2026-08-24). Chat is 1k in + 0.5k out. Repo review is 80k in + 4k out. Agent loop is 200k in with 50% cache hits + 20k out. Chart: i10X.<\/figcaption>\n<\/figure>\n

Cached agent: $1.05 vs $0.46. Gemini also gets cheaper cache reads if your stack actually hits cache. For subscription math, see\nAI subscription stack cost<\/a>.<\/p>\n\n

\n\n

Performance by job (not one score)<\/h2>\n

We are not inventing vision-eval or intelligence-index numbers we do not have in this pack. Cards, modalities, prices, and three live prompts. Re-run on your workload. Method:\nside-by-side AI comparison<\/a>.<\/p>\n\n

Coding and agents<\/h3>\n

Opus is positioned for end-to-end software, code review, and bug finding. Gemini 3.1 Pro Preview is positioned for enhanced software engineering and agentic reliability. Our micro-test: both named ZeroDivisionError<\/code> and guarded empty input with if not nums: return 0<\/code> (Opus used 0.0 and mentioned ValueError). Tie on correctness. Opus wrote more crash-path prose. Gemini wrote a clean short explanation. Do not crown a coding champion from one snippet. Cost still favors Gemini on the loop.<\/p>\n\n

Writing and tone<\/h3>\n

Both went warm. Opus: \u201cI hope you are doing well,\u201d finance promised Friday, flexible Wednesday, then the capture died at the competitive slide. Gemini (sanitized): \u201cI hope you are having a great week,\u201d client-name slot, same Tuesday\/Friday miss, Wednesday push, then the capture died at \u201cwe sti\u2026\u201d Extra greeting energy on Gemini is filler the source email did not contain. Opus was still warm, but closer to the ops facts we could see. Neither snippet in this pack is a finished letter. Score the voice, then re-run with a higher max-output if you need the Acme line on both.<\/p>\n\n

Research, math, reasoning<\/h3>\n

No science-QA pack here. False-premise: both refused the green-cheese Moon. Opus taught Apollo\/Luna geology. Gemini said a protein-mining plan is not possible, then offered to talk about Apollo or Artemis instead. Both pass. Opus more geological. Gemini more \u201cI will not build the false plan, here is a real-mission redirect.\u201d For publishable work, still use\nmulti-model hallucination checks<\/a>.<\/p>\n\n

Multimodal and long context<\/h3>\n

Windows are a hair: 1,000,000 vs 1,048,576. Modalities are not. Gemini lists audio and video. Opus lists text, image, file. If the job is meeting recordings, product video, or mixed media rooms, Gemini is the structural pick. If the job is long text plus screenshots, both cards can take it. We did not run a vision bake-off in this pack, so we will not invent one.<\/p>\n\n

Speed<\/h3>\n

No tok\/s in this pack. Writeups often say Gemini streams quickly. Measure p50 in your region. Do not ship on a screenshot.<\/p>\n\n\n\n\n\n\n\n\n\n

Job<\/p><\/th>\n

Edge<\/p><\/th>\n

Why<\/p><\/th>\n<\/tr>\n

Hard coding \/ agents<\/p><\/td>\n

Split<\/p><\/td>\n

Micro-test tie. Opus richer review. Gemini cheaper to loop.<\/p><\/td>\n<\/tr>\n

Everyday writing<\/p><\/td>\n

Claude Opus 5<\/p><\/td>\n

Less filler than Gemini on this prompt. Both captures truncated.<\/p><\/td>\n<\/tr>\n

Long docs \/ multimodal<\/p><\/td>\n

Gemini 3.1 Pro<\/p><\/td>\n

Audio\/video on the card. Similar context.<\/p><\/td>\n<\/tr>\n

Realtime \/ conversational<\/p><\/td>\n

Product-dependent<\/p><\/td>\n

Gemini app \/ Workspace vs Claude.ai. Not measured here.<\/p><\/td>\n<\/tr>\n

Cost at volume<\/p><\/td>\n

Gemini 3.1 Pro<\/p><\/td>\n

$2\/$12 vs $5\/$25, cheaper cache.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n

\nHow to read benchmarks<\/strong>\n

When we lack a primary public table for this exact pair, we do not invent one. Modality lists and live snippets are the honest floor.<\/p>\n<\/div>\n\n

\n\n

Side-by-side test (i10X pack, 2026-08-24)<\/h2>\n

Three prompts. Scores 1-5 on instruction following, depth, factual caution, style, and usefulness (max 25). No invented extra tests.<\/p>\n\n

Test 1: Client email rewrite<\/h3>\n

Task:<\/strong> Keep every fact. Warmer. Under 120 words.<\/p>\n

Claude Opus 5 (excerpt):<\/strong> Greeting. Q3 deck last Tuesday. Finance promised Friday, nothing received. Move next week, Wednesday preferred, happy to adjust. Stops at \u201cthe competitive slide.\u201d<\/p>\n

Gemini 3.1 Pro (excerpt, sanitized):<\/strong> Client-name slot. \u201cHope you are having a great week.\u201d Same Tuesday\/Friday miss, slightly softer \u201cjust yet.\u201d Wednesday push. Stops at \u201cwe sti\u2026\u201d Extra cheer that was not in the source.<\/p>\n

Edge:<\/strong> Opus, because the warmth is lighter and more operational. Both lose a point for truncated endings. Gemini loses more for filler.<\/p>\n\n

Test 2: Empty-list average bug<\/h3>\n

Both named ZeroDivisionError<\/code>. Both guard empty input before dividing. Opus added the 0\/0 crash path and a ValueError option. Gemini explained the missing empty check in one beat and shipped the same class of fix. Tie<\/strong> on this micro-task.<\/p>\n\n

Test 3: False premise (Moon cheese)<\/h3>\n

Opus (sanitized): folk joke, Apollo and Luna samples, basalt and anorthosite, no protein. Gemini: rocky body of minerals, dust, and basaltic rock. No cheese, no organics, protein mining plan is not possible. Redirect to Apollo or Artemis. Both pass.<\/strong> Gemini is stricter about not building the false plan. Opus teaches more rock.<\/p>\n\n\n\n\n\n\n\n\n

Prompt type<\/p><\/th>\n

Claude Opus 5<\/p><\/th>\n

Gemini 3.1 Pro<\/p><\/th>\n

Note<\/p><\/th>\n<\/tr>\n

Client email rewrite<\/p><\/td>\n

23\/25<\/p><\/td>\n

21\/25<\/p><\/td>\n

Both truncated. Gemini more filler.<\/p><\/td>\n<\/tr>\n

Bug explain + minimal fix<\/p><\/td>\n

24\/25<\/p><\/td>\n

24\/25<\/p><\/td>\n

Both catch ZeroDivisionError. Tie.<\/p><\/td>\n<\/tr>\n

Logic + false premise<\/p><\/td>\n

24\/25<\/p><\/td>\n

23\/25<\/p><\/td>\n

Both refuse. Opus more geology. Gemini refuses to plan on the false premise.<\/p><\/td>\n<\/tr>\n

Total<\/strong><\/p><\/td>\n

71\/75<\/strong><\/p><\/td>\n

68\/75<\/strong><\/p><\/td>\n

Opus on this prose pack. Gemini on cost and modalities.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Three editorial points do not erase audio\/video or a 2\u00d7-plus invoice. Route the next step.<\/p>\n\n

\n\n

Ecosystem and where you run them<\/h2>\n