Canonical URL Checker Calculator

Assess canonical tag coverage and the duplicate content risk that remains.

About Canonical URL Checker Calculator

Every indexable page should carry a self-referencing canonical as a baseline. Conflicting signals are worse than missing ones, because search engines may disregard canonicalisation for the whole site. Parameter URLs are the most common source of duplication, and canonical tags are the standard remedy where blocking is not appropriate.

Formula

Canonical URL Checker

Coverage = URLs with a canonical tag ÷ total indexable URLs

self-referencing canonical: A page declaring itself canonical, the correct default
conflicting canonical: Contradictory signals that cause the tag to be ignored

Worked example

With the default values below, Canonical URL Checker Calculator returns Canonical Tag Coverage of 90.000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total indexable URLsminimum 1: 12,000
URLs with a canonical tagminimum 0: 10,800
Self-referencing canonicalsminimum 0: 9,200
Conflicting or incorrect canonicalsminimum 0: 260
Parameter or duplicate variantsminimum 0: 3,400

Results

Canonical Tag Coverage: 90.000%
URLs Without a Canonical Tag: 1,200
Share With Conflicting Canonicals: 2.167%
Duplicate Variants per Canonical URL: 0.283
Verdict: Conflicting canonicals present — search engines may ignore the signal entirely

Step by step

1Values used
2Canonical URL Checker
3Canonical Tag Coverage= 90.000
4URLs Without a Canonical Tag= 1,200
5Share With Conflicting Canonicals= 2.167
6Duplicate Variants per Canonical URL= 0.283
7Verdict= Conflicting canonicals present — search engines may ignore the signal entirely

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Canonical URL Checker calculated?

Coverage = URLs with a canonical tag ÷ total indexable URLs Every indexable page should carry a self-referencing canonical as a baseline. Conflicting signals are worse than missing ones, because search engines may disregard canonicalisation for the whole site.

Why does Canonical URL Checker matter?

Parameter URLs are the most common source of duplication, and canonical tags are the standard remedy where blocking is not appropriate.

What values do I need to enter?

This calculator takes 5 inputs: Total indexable URLs, URLs with a canonical tag, Self-referencing canonicals, Conflicting or incorrect canonicals, Parameter or duplicate variants. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.