RAG Chunk Size Calculator

Estimate chunk counts for your document corpus.

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What the RAG Chunk Size Calculator — Free Online Tool does

The RAG Chunk Size Calculator is a free page for reasoning about chunk size in a retrieval-augmented generation pipeline. It focuses on the trade-off between retrieval quality and context-window usage: chunks that are too small lose meaning, while chunks that are too large dilute search and consume tokens. It is aimed at developers tuning document ingestion and retrieval. No sign-up is required. Validate any suggested size with retrieval tests on your own corpus.

How to use it

  1. Review the structure of the documents you ingest.
  2. Estimate a starting chunk size for that structure.
  3. Set an overlap for boundaries that split answers.
  4. Test retrieval quality and answer accuracy at that size.
  5. Tune the size and overlap based on measured recall.

FAQ

What is a good chunk size for RAG?

Common starting points are a few hundred tokens with modest overlap, but the right value depends on document structure and query type. Technical manuals, contracts and chat logs each behave differently. Evaluate recall and answer quality across several sizes rather than fixing one by convention.

Should chunks overlap?

A small overlap helps when an answer spans a boundary and would otherwise be split. Too much overlap increases index size, embedding cost and duplicate retrieval. Start with a modest overlap, then reduce it if retrieval returns near-identical neighbours.

Does chunk size affect cost?

Yes. Smaller chunks mean more vectors to store and search, while larger chunks send more tokens to the model on every query. Both affect spend. Plugsky's embedding and chat APIs are OpenAI-compatible, so you can measure different chunking strategies on the free plan, which includes 2 free models.

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Canonical pricing and plans: plugsky.com/#sec-pricing · Terms · SLA · Docs

Related

RAG Docs

RAG API

Plugsky Embed Model Guide: Dimensions and RAG Use Cases