Find the Co-factor Matrix
Find the cofactor matrix. Runs entirely in your browser, so your data never leaves your device.
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Output
The result appears here as you type.
How to use Find the Co-factor Matrix
- 1. Paste your square matrix. Enter a square matrix in the input pane, one row per line. Cofactors are only defined for square matrices, so rows and columns must match.
- 2. Set the decimal precision. Enter a value in Decimal places to control how many digits after the decimal point appear in each cofactor's computed value.
- 3. Copy the cofactor matrix. Copy the resulting matrix of signed minors into your adjugate calculation, determinant expansion, or linear algebra write-up.
When to use Find the Co-factor Matrix
Find the Co-factor Matrix computes the matrix of signed minors for a square matrix, the building block for the adjugate matrix and for cofactor expansion of a determinant. It replaces a tedious cell-by-cell hand calculation.
- Building toward an adjugate or inverse. You need the cofactor matrix as an intermediate step before transposing it into the adjugate to compute a matrix inverse, and this handles that step directly.
- Checking a determinant expansion by minors. A homework problem expands a determinant along a row using cofactors, and computing the full cofactor matrix here lets you check each individual signed minor.
- Verifying a linear algebra proof step. You are working through a proof involving the relationship between a matrix and its cofactors and want a concrete numeric example to confirm your reasoning holds.
- Teaching signed minors in a course. A linear algebra lesson on cofactor expansion benefits from a generated cofactor matrix example, showing students how each entry's sign alternates across the grid.
Examples
Cofactors of a 2×2 matrix
Input
1 2 3 4
Output
4 -3 -2 1
Cofactors of a 3×3 matrix
Input
1 2 3 4 5 6 7 8 10
Output
2 2 -3 4 -11 6 -3 6 -3
About the Find the Co-factor Matrix tool
Find the Co-factor Matrix is a free online tool that works entirely inside your web browser. Find the cofactor matrix. Because the processing happens on your own device, nothing you enter is uploaded, logged or stored anywhere.
This page is one of 234 Math utilities on EditSafely. Each one does a single job well, and all of them follow the same rule: your input stays on your machine.
You can shape the output with the Decimal places setting, and the result refreshes the moment you change it. 2 worked examples further down the page show exactly what the tool produces for real inputs.
Because nothing leaves your device, the tool is suitable for sensitive content such as internal documents, credentials or customer data. It also responds instantly, since every keystroke is handled on your own machine rather than by a remote API.
Frequently asked questions
Is Find the Co-factor Matrix free to use?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
Everything happens locally. Your browser downloads the tool's code once, then does all the processing itself; nothing you enter is transmitted, stored or logged. You can even go offline after the page loads and it will still work.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
No. The tool works in any modern browser on desktop, tablet or phone. There is no account to create, no extension to add and no software to install.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.