Claude Opus 5.5
- Input / 1M tokens
- $4.00
- Output / 1M tokens
- $20.00
API models · Side by side
Claude Opus 5.5 vs Gemini 3.8 Flash
This pair is useful when a project needs both substantial text work and mixed-media input. Opus and Gemini overlap on documents and images, but recordings, response size and token costs separate them.
Gemini 3.8 Flash
- Input / 1M tokens
- $0.75
- Output / 1M tokens
- $3.75
The short answer
Gemini has lower base text-token rates and accepts audio and video. Opus offers a larger maximum output allowance. Neither fact alone determines which produces the more useful answer for your task.
Compare the details
Compare context, supported inputs and usage costs. Highlighted rows show a difference.
| Feature | Claude Opus 5.5 | Gemini 3.8 Flash |
|---|---|---|
| Input formats | file, image, text | audio, file, image, text, video |
| Output formats | text | text |
| Context / position limit | 1,000,000 | 1,048,576 |
| Maximum output tokens | 128,000 | 65,536 |
| Developer features | Reasoning output, Completion limit, Output limit, Reasoning controls, Thinking effort, Response format, Stop sequences, Structured output, Tool selection, Tool calling, Response length | Reasoning output, Output limit, Reasoning controls, Thinking effort, Response format, Seed, Stop sequences, Structured output, Temperature, Tool selection, Tool calling, Sampling controls |
| Cached input / 1M tokens | $0.20 | $0.08 |
| Cache write / 1M tokens | $5.00 | $0.04 |
| USD input / 1M tokens | $4.00 | $0.75 |
| USD output / 1M tokens | $20.00 | $3.75 |
| Model identifier | anthropic/claude-opus-5.5 | google/gemini-3.8-flash |
API pricing
Prices are in USD per million tokens. Input is what you send; output is what the model generates. Claude and ChatGPT subscriptions are billed separately.
Tools, images and additional reasoning can add charges. The examples below cover input and output tokens only.
Compare local modelsWhat those prices mean in practice
Each example uses the same token budget for both models. These are calculations, not measured workloads. Cache discounts, media, tools and extra reasoning are excluded.
| Workload | Claude Opus 5.5 | Gemini 3.8 Flash |
|---|---|---|
| 1,000 short requestsPer request: 2,000 input + 500 output tokens | $18.00 | $3.38 |
| 100 document summariesPer request: 20,000 input + 1,000 output tokens | $10.00 | $1.88 |
| 10 long-document requestsPer request: 300,000 input + 2,000 output tokens | $12.40 | $2.33 |
Estimate = requests × (input tokens × input price + output tokens × output price) ÷ 1,000,000. Long-prompt rates are applied where the pricing data provides them. Real requests can use different amounts of output.
Beyond the price tag
A document assistant or a media assistant?
For contracts, manuals or screenshots, both models support the relevant input categories. A workflow that receives recordings or video directly has a concrete reason to consider Gemini. With Opus, the same workflow would need another stage to transcribe audio or extract visual information. That stage changes what the model sees and can introduce omissions, storage and processing costs. Describe the incoming material before picking the model.
The price of a finished report
For long reports, the output rate matters alongside the source-document size. Gemini’s lower rate may make repeated drafting cheaper at equal token counts, but its maximum output allowance is smaller here. Opus permits a longer individual response. Large outputs also need review: splitting a report into sections can make checking easier, provided the application carries the important context across requests.
Search and tool use
Both expose tool and structured-response features. Built-in search, external tool calls and reasoning can add work beyond an ordinary text request. The examples compare only the stated input and output counts. For a research assistant, budget searches and retrieval separately, then decide how the application will check claims and preserve the material needed by a reviewer. A supported search option is not evidence that an answer is correct.
Choose around the missing capability
If the application needs video or audio input, Gemini fills that requirement in this pair. If the feature already relies on a Claude workflow and needs substantial text output, Opus remains a candidate. For overlapping text tasks, compare the final deliverable and total spend using representative work. Avoid choosing solely from a model-family label: the useful difference is what your product needs and what the request actually costs.
Common questions
Can either model run on my laptop?
These compared endpoints are hosted services. This page does not describe downloadable weights for local deployment.
Does the larger output allowance mean better writing?
No. It describes the maximum response budget. Readability, correctness and useful detail need to be assessed on the actual deliverable.