Neither wins outright: Anthropic: Claude Fable 5.1 is the pick when you need built-in web search, Google: Gemini 2.5 Flash Lite Preview 09-2025 when cost matters at scale.
| Spec | Anthropic: Claude Fable 5.1 | Google: Gemini 2.5 Flash Lite Preview 09-2025 |
|---|---|---|
| Provider | Anthropic | |
| Input price (per 1M tokens) | $10.00 | $0.10 |
| Output price (per 1M tokens) | $50.00 | $0.40 |
| Blended price (3:1 input/output) | $20.00 | $0.18 |
| Cheaper than … of all models we track | 3% | 71% |
| Context window | 1M tokens (~1,500 pages) | 1.0M tokens (~1,573 pages) |
| Larger context than … of all models | 69% | 81% |
| Max output per response | 128K tokens (~96,000 words) | 66K tokens (~49,200 words) |
| Input types | text, image, file | text, image, file, audio, video |
| Output types | text | text |
| Free variant | No | No |
| Listed since | 2026-09-01 | 2025-09-25 |
Monthly cost at list price for five common workloads. Token counts per unit are stated so you can scale them to your own traffic. A workload that does not fit a model's context window is marked rather than priced.
| Workload (per month) | Anthropic: Claude Fable 5.1 | Google: Gemini 2.5 Flash Lite Preview 09-2025 | Difference |
|---|---|---|---|
| Customer-support chatbot 50,000 conversations — each a 6-turn conversation (1,500 in / 400 out tokens) | $1,750 | $15.50 | Google: Gemini 2.5 Flash Lite Preview 09-2025 saves $1,735 |
| RAG search over documents 20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens) | $1,700 | $16.00 | Google: Gemini 2.5 Flash Lite Preview 09-2025 saves $1,684 |
| Coding / tool-using agent 2,000 tasks — each a multi-step task with tool calls and file context (60,000 in / 6,000 out tokens) | $1,800 | $16.80 | Google: Gemini 2.5 Flash Lite Preview 09-2025 saves $1,783 |
| Batch summarisation 10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens) | $1,100 | $10.40 | Google: Gemini 2.5 Flash Lite Preview 09-2025 saves $1,090 |
| Long-document analysis 500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens) | $550 | $5.40 | Google: Gemini 2.5 Flash Lite Preview 09-2025 saves $545 |
| Capability | Anthropic: Claude Fable 5.1 | Google: Gemini 2.5 Flash Lite Preview 09-2025 | What it lets you do |
|---|---|---|---|
| Tool / function calling | ✓ Yes | ✓ Yes | call your APIs and run agent loops |
| Structured output (JSON schema) | ✓ Yes | ✓ Yes | return JSON that validates against your schema |
| Reasoning / thinking mode | ✓ Yes | ✓ Yes | spend extra tokens thinking before answering hard problems |
| Image input | ✓ Yes | ✓ Yes | read screenshots, charts and scanned pages |
| Audio input | — | ✓ Yes | take speech or audio directly |
| File / PDF input | ✓ Yes | ✓ Yes | accept documents without your own parsing step |
| Image output | — | — | generate images, not just text |
| Built-in web search | ✓ Yes | — | answer from live web results |
| Seed (reproducible sampling) | — | ✓ Yes | repeat a generation for tests and evals |
| Log-probabilities | — | — | read token confidence for classification and scoring |
From each model's published parameters and input/output types. “—” means not advertised, not proven absent.
Neither wins outright: Anthropic: Claude Fable 5.1 is the pick when you need built-in web search, Google: Gemini 2.5 Flash Lite Preview 09-2025 when cost matters at scale. In short: Anthropic: Claude Fable 5.1 when you need built-in web search, you generate long outputs in one go, you want the newer model; Google: Gemini 2.5 Flash Lite Preview 09-2025 when cost matters at scale, you need audio input, you need seed (reproducible sampling).
Google: Gemini 2.5 Flash Lite Preview 09-2025 is cheaper: $0.18 vs $20.00 per 1M tokens at a typical 3:1 input/output mix, 99% less. For 50,000 support conversations a month that is $15.50 against $1,750.
Anthropic: Claude Fable 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens; Google: Gemini 2.5 Flash Lite Preview 09-2025 costs $0.10 input and $0.40 output. Output tokens are billed separately, so long answers shift the gap.
Google: Gemini 2.5 Flash Lite Preview 09-2025: 1.0M tokens, about 1,573 pages, against 1M (about 1,500 pages) for Anthropic: Claude Fable 5.1.
Tool calling — Anthropic: Claude Fable 5.1: yes, Google: Gemini 2.5 Flash Lite Preview 09-2025: yes. JSON-schema structured output — Anthropic: Claude Fable 5.1: yes, Google: Gemini 2.5 Flash Lite Preview 09-2025: yes.
Yes, both accept image input.
No free variant is listed for either; both are pay-per-token.
Anthropic: Claude Fable 5.1 can write up to 128K tokens (about 96,000 words) per response; Google: Gemini 2.5 Flash Lite Preview 09-2025 up to 66K (about 49,200 words).
Anthropic: Claude Fable 5.1 was listed on 2026-09-01; Google: Gemini 2.5 Flash Lite Preview 09-2025 on 2025-09-25.
Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...
Full Anthropic: Claude Fable 5.1 specs →Gemini 2.5 Flash-Lite is a lightweight reasoning model in the Gemini 2.5 family, optimized for ultra-low latency and cost efficiency. It offers improved throughput, faster token generation, and better performance across common benchmarks compared to earlier Flash models. By default, "thinking" (i.e. multi-pass reasoning) is disabled to prioritize speed, but developers can enable it via the [Reasoning API parameter](https://openrouter.ai/docs/use-cases/reasoning-tokens) to selectively trade off cost for intelligence.
Full Google: Gemini 2.5 Flash Lite Preview 09-2025 specs →