diff --git a/docs/custom-api.md b/docs/custom-api.md
index 49502e6..f4102f7 100644
--- a/docs/custom-api.md
+++ b/docs/custom-api.md
@@ -238,7 +238,7 @@ Output:
 <div>90</div>
 ```
 
-Other operations include `add`, `mul`, and `div`.
+Other operations include `add`, `mul`, `div` and `mod`.
 
 <hr>
 
@@ -431,6 +431,7 @@ The following helper functions provided by Glance are available:
 - `sub(a, b float) float`: Subtracts two numbers.
 - `mul(a, b float) float`: Multiplies two numbers.
 - `div(a, b float) float`: Divides two numbers.
+- `mod(a, b int) int`: Remainder after dividing a by b (a % b).
 - `formatApproxNumber(n int) string`: Formats a number to be more human-readable, e.g. 1000 -> 1k.
 - `formatNumber(n float|int) string`: Formats a number with commas, e.g. 1000 -> 1,000.
 - `trimPrefix(prefix string, str string) string`: Trims the prefix from a string.
diff --git a/internal/glance/widget-custom-api.go b/internal/glance/widget-custom-api.go
index 3d94eb6..d95d885 100644
--- a/internal/glance/widget-custom-api.go
+++ b/internal/glance/widget-custom-api.go
@@ -414,6 +414,14 @@ func customAPIDoMathOp[T int | float64](a, b T, op string) T {
 			return 0
 		}
 		return a / b
+	case "mod":
+		ai, bi := any(a), any(b)
+		aint, aok := ai.(int)
+		bint, bok := bi.(int)
+		if aok && bok && bint != 0 {
+			return T(aint % bint)
+		}
+		return 0
 	}
 	return 0
 }
@@ -479,6 +487,9 @@ var customAPITemplateFuncs = func() template.FuncMap {
 		"div": func(a, b any) any {
 			return doMathOpWithAny(a, b, "div")
 		},
+		"mod": func(a, b int) any {
+			return doMathOpWithAny(a, b, "mod")
+		},
 		"now": func() time.Time {
 			return time.Now()
 		},