HTML Link Extractor
Extract href values and link text from pasted HTML and resolve relative links against your supplied base URL.
Open toolCanonical URL Checker
Check the markup and resolution rules for a page URL. Provide HTML, Page URL to compute results directly in your browser. Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google.
Free to useNo sign-upRuns in your browser
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How the Canonical URL Checker Works & Core Formula
The Canonical URL Checker evaluates HTML, Page URL in client-side JavaScript using the deterministic rule below and updates the output panel immediately without uploading data to a server.
rel is tokenized case-insensitively; canonical URLs resolve against the first base href or the supplied page URL.
Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google.
Canonical URL Checker Quick Reference & Input Guide
Review the input parameters, allowed value ranges, and worked reference cases for the Canonical URL Checker below before running your calculation.
| Parameter / Scenario | Default / Sample Value | Rule or Allowed Range | Output / Usage Note |
|---|---|---|---|
| Input: HTML | <base href="/docs/"><link rel="ca... | Input type: textarea | Required workspace parameter |
| Input: Page URL | https://example.com/article | Input type: text | Required workspace parameter |
| Worked Case 1: Starting inputs | Preloaded / test values | rel is tokenized case-insensitively; canonical URLs resolve against the first base href or the supplied page URL | HTML = <base href="/docs/"><link rel="canonical" href="guide">; Page URL = https://example.com/article |
| Worked Case 2: Comparison scenario (google canonical url checker) | Preloaded / test values | rel is tokenized case-insensitively; canonical URLs resolve against the first base href or the supplied page URL | HTML = <link rel="CANONICAL alternate" href="/a"><link rel="canonical" href="https://example.com/b">; Page URL = https://example.com/article |
Step-by-Step Guide to Using the Canonical URL Checker
Follow these three steps to configure HTML, Page URL, verify unit and boundary rules, and export your Canonical URL Checker output.
Input and settings
Tool result
Review the details
Practical Worked Examples for Canonical URL Checker
These concrete scenarios illustrate how the Canonical URL Checker processes baseline inputs, comparison checks, and boundary constraints.
Starting inputs
HTML = <base href="/docs/"><link rel="canonical" href="guide">; Page URL = https://example.com/article
Comparison scenario (google canonical url checker)
HTML = <link rel="CANONICAL alternate" href="/a"><link rel="canonical" href="https://example.com/b">; Page URL = https://example.com/article
Boundary & unit check (Canonical URL Checker)
When solving for 'canonical url checker', verify that HTML, Page URL use consistent units and stay within the documented scope: Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google.
How to Read and Verify the Canonical URL Checker Output
The output panel reports the exact result derived from HTML, Page URL alongside any unit or formatting notes.
Every calculation follows the rule: rel is tokenized case-insensitively; canonical URLs resolve against the first base href or the supplied page URL. Because JavaScript uses IEEE 754 double-precision floating-point arithmetic, numeric outputs display up to 12 significant digits where applicable.
Always cross-check the displayed result against the scope note (Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google) before applying the value to production specifications, financial models, or lab records.
Scope Limits, Accuracy Assumptions & Related Web & Accessibility Tools
Review these boundary constraints and validation rules before relying on the Canonical URL Checker output.
Operational scope: Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google. Inputs that violate minimum/maximum bounds or required format rules are rejected with a clear diagnostic prompt.
Need an adjacent calculation in Web & Accessibility? Use the related tools linked below to chain your workflow without leaving your browser.
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Open toolFrequently Asked Questions About Canonical URL Checker
Answers about using Canonical URL Checker and understanding its results.
What formula or rule does the Canonical URL Checker use?
The Canonical URL Checker applies the rule: rel is tokenized case-insensitively; canonical URLs resolve against the first base href or the supplied page URL. Enter HTML, Page URL into the workspace and the tool computes the exact output in your browser.
What input parameters and units are required for Canonical URL Checker?
Yes. Provide HTML, Page URL using the documented units and format shown in the quick reference table above. Preloaded default values let you test the workflow immediately.
What are the accuracy limits and boundary assumptions for Canonical URL Checker?
Checks pasted markup only, up to 100,000 UTF-16 units and 100 canonical elements, using an unmounted template. The first base href is used; a malformed or non-HTTP(S) first base falls back to the supplied page URL. Duplicate equivalent targets and distinct conflicts are reported separately. This cannot show indexing status or the canonical chosen by Google. Confirm that your inputs fall within the allowed ranges before exporting the result.
Is the Canonical URL Checker free and does it keep my inputs private?
Yes. All calculations for the Canonical URL Checker execute 100% locally in your browser's JavaScript runtime. No inputs or results are uploaded to any external server.
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