diff --git a/README.md b/README.md
index 8aa7dfc..970d4ea 100644
--- a/README.md
+++ b/README.md
@@ -68,11 +68,12 @@ arrays gets those arrays joined together.
 
 ### Documentation
 
-#### `algorithm(inset: 0.2em, indent: 0.5em, vstroke: 0pt + luma(200), line-numbers: true, ..bits)`
+#### `algorithm(inset: 0.2em, indent: 0.5em, vstroke: 0pt + luma(200), line-numbers: true, line-numbers-format: x => [#x:], ..bits)`
 
 This is the main function of the package. It takes a list of arrays and
 returns a typesetting of the algorithm. You can modify the inset
 between lines with the `inset` parameter.
+If you want to customize line numbers, you can pass a function, that takes a number and returns **content**, to the `line-numbers-format` parameter instead of a default value.
 
 ```typst
 #algorithm(
@@ -80,6 +81,7 @@ between lines with the `inset` parameter.
   indent: 0.5em, // indentation for the algorithm
   vstroke: 0pt + luma(200), // vertical stroke for indentation guide
   line-numbers: true, // show line numbers
+  line-numbers-format: x => [#x:], // change the line numbers format
   { // provide an array
     import algorithmic: * // import all names in the array
     Assign[$x$][$y$]
@@ -96,7 +98,7 @@ between lines with the `inset` parameter.
 ```
 ![image of the algorithm with three lines of code assigning x to y, y to x, and z to x + y. The inset is set to 1em, the indent to 0.5em](https://raw.githubusercontent.com/typst-community/typst-algorithmic/refs/tags/v1.0.6/tests/algorithm/ref/1.png)
 
-#### `algorithm-figure(title, supplement: "Algorithm", inset: 0.2em, indent: 0.5em, vstroke: 0pt + luma(200), line-numbers: true, ..bits)`
+#### `algorithm-figure(title, supplement: "Algorithm", inset: 0.2em, indent: 0.5em, vstroke: 0pt + luma(200), line-numbers: true, line-numbers-format: x => [#x:], ..bits)`
 
 The `algorithm-figure` function is a wrapper around `algorithm` that returns a
 figure element of the algorithm. It takes the same parameters as
diff --git a/algorithmic.typ b/algorithmic.typ
index 8ddb5b0..e537b96 100644
--- a/algorithmic.typ
+++ b/algorithmic.typ
@@ -62,6 +62,7 @@
   indent: 0.5em,
   vstroke: 0pt + luma(200),
   line-numbers: true,
+  line-numbers-format: x => [#x:],
   horizontal-offset: 1.63640em,
   ..bits,
 ) = {
@@ -86,7 +87,9 @@
   }
 
   while line-number <= content.len() {
-    if line-numbers { grid-bits.push([#line-number:]) }
+    if line-numbers {
+      grid-bits.push(line-numbers-format(line-number))
+    }
     grid-bits = grid-bits + indent-content.at(line-number - 1)
     grid-bits.push(grid.cell(
       content.at(line-number - 1).line-content,
@@ -110,6 +113,7 @@
   indent: 0.5em,
   vstroke: 0pt + luma(200),
   line-numbers: true,
+  line-numbers-format: x => [#x:],
   horizontal-offset: 1.63640em,
   ..bits,
 ) = {
@@ -122,6 +126,7 @@
       inset: inset,
       vstroke: vstroke,
       line-numbers: line-numbers,
+      line-numbers-format: line-numbers-format,
       horizontal-offset: horizontal-offset,
       ..bits,
     ),
diff --git a/tests/line-numbers-format/.gitignore b/tests/line-numbers-format/.gitignore
new file mode 100644
index 0000000..40223be
--- /dev/null
+++ b/tests/line-numbers-format/.gitignore
@@ -0,0 +1,4 @@
+# generated by tytanic, do not edit
+
+diff/**
+out/**
diff --git a/tests/line-numbers-format/ref/1.png b/tests/line-numbers-format/ref/1.png
new file mode 100644
index 0000000..ab55aa2
Binary files /dev/null and b/tests/line-numbers-format/ref/1.png differ
diff --git a/tests/line-numbers-format/test.typ b/tests/line-numbers-format/test.typ
new file mode 100644
index 0000000..d2a497a
--- /dev/null
+++ b/tests/line-numbers-format/test.typ
@@ -0,0 +1,13 @@
+#import "../../algorithmic.typ"
+#import algorithmic: *
+#set page(margin: .1cm, width: 2cm, height: auto)
+
+#algorithm(
+  line-numbers-format: num => str(num) + "|",
+  {
+    import algorithmic: *
+    for i in range(1, 5) {
+      Assign($y$, str(i))
+    }
+  },
+)