Private, browser-only planning tool

Kimi Context & File Fit Checker

Estimate whether pasted or local plain-text content is likely to fit a documented Kimi context window after reserving room for the answer and existing conversation. This is a transparent heuristic, not a Kimi tokenizer or a live product test.

Your text and file stay in this browser. Nothing is uploaded by this checker.

Content and context

Paste text, optionally read one supported local text-like file, and choose the product surface you plan to use.

Kimi surface and model Chat, API and Kimi Code are separate products. Plan access and usable capacity can differ.

Paste text Pasted text and readable local-file text are counted together. 0 pasted characters 0 local-file characters 0 approximate words

Optional local text-like file For privacy, the browser reads only one allowlisted plain text-like file, locally, up to 5 MiB. PDF, Word, spreadsheet, presentation, image, audio, video and archive files are not parsed here.

No local file selected.

Approximation profile These ratios are editorial planning heuristics, not official Kimi tokenizer values. The fit verdict uses the high end of the displayed range.

Output reserve (tokens) Editable planning reserve. No official Chat output default is applied.

Other context tokens Existing conversation, system prompts, tool definitions or known overhead.

Fit estimate

The cautious result uses the high end of the estimated token range.

Kimi Chat — K2.6 Uses about 128K as a planning reference from consumer troubleshooting guidance, not a guaranteed hard limit.

Planning verdict Fits with headroom The current reserves use 6.4% of the selected planning window.

Approximate text tokens 0 Auto: English prose profile

Cautious range 0–0 Low to high estimate

Selected context window about 128K Surface-specific documented reference

Cautious planned use 8,192 High text estimate + both reserves

Context budget used 6.4%

No split required by this estimate

There is substantial numerical headroom. For important files, still work by logical sections and verify coverage against the source.

Limits, method and evidence

Official Kimi Chat upload limits

100 MB / file 50 files / session

Kimi’s consumer overview lists PDF, Word, Excel, PowerPoint, images, TXT and video. These are upload ceilings, not a promise that every page, cell, slide or frame will be extracted accurately.

Scope: consumer Kimi Chat documentation. Do not assume these limits apply unchanged to the API, Kimi Code or a third-party client.

Agent is excluded from the selector: its published 256K figure is stated in characters, not tokens, so it is not interchangeable with the token windows calculated here.

Official Kimi API Files limits

100 MB / file 1,000 files / user 10 GB storage

These limits belong to the Global Kimi API Files service. They are distinct from the consumer Chat limit of 50 files per session and from a model’s token context window.

Approximation method

The checker counts Unicode characters in pasted and locally read text. It converts characters to a midpoint and a deliberately wide range:

low = characters ÷ (profile ratio + 1)
midpoint = characters ÷ profile ratio
high = characters ÷ max(1, profile ratio − 1)

Ratios: English prose 4, code/structured text 3.5, mixed/non-Latin text 2. Auto uses simple character and punctuation signals. The high estimate drives the fit verdict.

For a request-level API count, use Kimi’s authenticated Estimate Token Count endpoint with the complete messages payload, then add the intended output reserve. Keep API keys server-side; this public checker intentionally never asks for one.

Important limitations

This is not the official Kimi tokenizer and does not call Kimi.
Tokenization varies with language, code, whitespace, markup and model implementation.
File bytes do not predict extracted tokens for PDF, Office, image, audio or video formats, so this tool does not parse them.
Clients can compact, truncate or add hidden context before a model limit is reached.
A numerical fit does not prove complete retrieval, accurate extraction or a successful upload.
Kimi Code 1M access is plan-dependent; Kimi Chat availability can depend on product mode and account.

Official sources and verification date

Facts were checked against official Kimi documentation on August 4, 2026. Product documentation and entitlements can change.

Built by KI AI Team for Kimi AI Guide. This independent planning tool is not affiliated with Moonshot AI or Kimi. No live file-processing or maximum-context test is claimed.