Free patent drawing checker tools, compared

Short answer: three tools we could open check drawings against the measurable parts of 37 CFR 1.84. PatentQuill’s is free with no account and keeps your file in your browser. PatentStroke and PatentFig charge credits per check and require sign-in. MaxVal offers a free review by people, not software. Two other names you may come across, AnalyzeImage and Kirschner, could not be checked. None of them tells you the USPTO will accept your drawings. Facts below come from each tool’s public page, checked 2026-11-11.

Try the free checker USPTO drawing requirements

At a glance

Illustration: summary of the table below, as stated on each tool’s public page, checked 2026-11-11. *PatentStroke says its pixel measurements run in the browser and its AI review sends the image to a model provider. “Not stated” means the page did not say.

“Credits” means a paid-by-credit check with some free credits on sign-up, as the tool’s page states. Allowances can change; open the linked page for the current terms.

What each tool says it does

Wording is paraphrased from each tool’s own page on 2026-11-11. We did not run the competing checkers on test files, so we make no claim about how accurate their results are.

Tool	Cost	Your file	What it tests	Output
PatentQuill checker Checked 2026-11-11	Free, no account.	Read in your browser tab; nothing is uploaded. PDF, PNG or JPG.	Six measurable points: margins (top 2.5, left 2.5, right 1.5, bottom 1 cm), black lines with no gray, letter height against 0.32 cm, FIG. labels, sheet numbers, repeated reference numerals. Each result names the requirement it tests; it does not print a paragraph number on every line.	Per-sheet list marked pass, fail or “by eye”. Scans and images have no text layer, so letter height, labels and sheet numbers are “by eye”.
PatentStroke figure checker Checked 2026-11-11	Sign-in required; each check costs 20 credits. The page says new accounts get 30 free credits on sign-up day and 10 more daily.	PNG, JPG or WebP up to 10 MB. The page says pixel measurements run in your browser and an AI review sends the image to a model provider.	Names 37 CFR 1.84 paragraphs (a), (b), (f), (g), (l), (p)(3) and CNIPA rules. Lists resolution, margins, sheet size, color, line weight, numeral height, FIG. labels, lead lines and file type.	Itemised report: each check passed, warning or failed, with its source rule. The page says AI-estimated numeral heights are approximate.
PatentFig figure checker Checked 2026-11-11	Home page says “Check a figure free”; the checker page says each check costs 20 credits and asks you to sign in. Free allowance not stated on that page.	Where processing happens is not stated on the page. Accepted file types are listed inconsistently (PNG, JPG, PDF on one line; PNG, JPEG, TIFF, WebP on another).	Names 37 CFR 1.84 (a)(1), (f), (g), (l), (p)(3), (q) and PCT Rule 11. Margins, line weight, resolution, color mode, numeral height, lead lines, sheet size.	Itemised report of passes and likely objections by category (DPI, format, color, text, line art).
MaxVal free drawing review Checked 2026-11-11	Page says the audit is “free of charge” and “no commitment required”. A service firm offering it.	You send your drawings to the firm. Accepted formats are not listed on the page.	A team reviews your drawings; the page does not list specific checks.	A human reply on “what, if anything, needs to change”. Not automated software.

Could not be checked

AnalyzeImage: A name that circulates as a free checker. Its site could not be reached from our check (connection closed) and a web search for “analyzeimage patent drawing” returned no matching tool. Could not be checked.
Kirschner: A name that circulates as a free checker. Searches for it together with “patent drawing checker” returned no matching tool or site. Could not be checked.
drawlint (Hugging Face Space): A Space titled “patent drawing checker” exists, and a search listing describes SVG and PDF checks against 37 CFR 1.84. The Space page itself shows no description, cost or processing details, and its app page returned an error. Could not be fully checked.

Where the PatentQuill checker is different

Free and no account. Nothing is spent per check and there is no sign-in step.
The file stays in your tab. The checker reads PDF, PNG or JPG with the browser; there is no upload to a server. That matters when an application is still unpublished.
Measured against named requirements. Margins, black lines, letter height, FIG. labels, sheet numbers and repeated numerals, each reported on the sheet where it occurs.

Illustration of how the free checker works; not a screenshot. Letter height, FIG. labels and sheet numbers are read from a PDF’s text layer; on scans and images they are marked “by eye”.

Illustration, not a PatentQuill output. Real tools can mix both lanes: PatentStroke says pixel measurements run in your browser while its AI review sends the image on. Compare the lanes when your application is still unpublished.

What we do not do

It is not legal advice, and a clean report is not a promise the USPTO will accept the sheets.
It does not test resolution (dpi), line weight or file type; two of the tools above list those checks.
It does not judge content, such as whether every claimed feature is shown. That stays the filer’s call.
On scans and images, letter height, labels and sheet numbers are marked “by eye” for you to confirm.

40-second walkthrough: paste, generate, edit, export. Animation built from a real PatentQuill output (US 6,269,361 B1, FIG. 1, public patent text); it is not a live screen recording.

Rules in plain language: USPTO patent drawing requirements. To run the check now: free patent drawing checker. PatentQuill also draws the sheets: flowcharts and block diagrams.

Sources

PatentStroke figure checker · checked 2026-11-11
PatentStroke home (pricing, privacy wording) · checked 2026-11-11
PatentFig figure checker · checked 2026-11-11
PatentFig home · checked 2026-11-11
MaxVal patent drawings guide (free review) · checked 2026-11-11
drawlint Space (Hugging Face) · checked 2026-11-11
37 CFR 1.84 (Cornell LII) · checked 2026-11-11

Third-party pages change. If something here is out of date, the tool’s own page is the authority.

Questions

Is there a free tool that checks patent drawings against 37 CFR 1.84?

Yes, in two senses. PatentQuill’s checker is free with no account and runs in your browser. PatentStroke and PatentFig offer checks paid in credits, with some free credits on sign-up. Prices and allowances change, so read each page before relying on them.

Does passing a checker mean the USPTO will accept my drawings?

No. Every tool here measures what can be measured on the sheet. Whether the drawings show each claimed feature, and whether an examiner accepts them, is not something software decides. PatentQuill does not provide legal advice; check the official sources before you file.

Does my drawing get uploaded when I use a checker?

It depends on the tool. PatentQuill’s checker reads the file inside your browser tab. PatentStroke says its pixel measurements run in your browser but its AI review sends the image to a model provider. For PatentFig and MaxVal the pages we read did not say where processing happens. If the application is unpublished, read each privacy policy first.

What does the PatentQuill checker not do?

It does not test resolution (dpi), line weight or file type, which the PatentStroke and PatentFig pages list. It does not judge content, such as whether every claimed step is shown. Scanned sheets get “by eye” marks for letter height, labels and sheet numbers.

Why are AnalyzeImage and Kirschner not compared?

We could not find a working page for either one on 2026-11-11. We would rather say so than describe a tool we have not seen.

PatentQuill is a drafting tool and does not provide legal advice. Check the official sources before you file.