diff --git a/lib/std/math/complex.zig b/lib/std/math/complex.zig
index 447b5f9fc2..42342faa3e 100644
--- a/lib/std/math/complex.zig
+++ b/lib/std/math/complex.zig
@@ -88,6 +88,22 @@ pub fn Complex(comptime T: type) type {
             };
         }
 
+        /// Returns the negation of a complex number.
+        pub fn neg(self: Self) Self {
+            return Self{
+                .re = -self.re,
+                .im = -self.im,
+            };
+        }
+
+        /// Returns the product of complex number and i=sqrt(-1)
+        pub fn mulbyi(self: Self) Self {
+            return Self{
+                .re = -self.im,
+                .im = self.re,
+            };
+        }
+
         /// Returns the reciprocal of a complex number.
         pub fn reciprocal(self: Self) Self {
             const m = self.re * self.re + self.im * self.im;
@@ -146,6 +162,20 @@ test "complex.conjugate" {
     try testing.expect(c.re == 5 and c.im == -3);
 }
 
+test "complex.neg" {
+    const a = Complex(f32).init(5, 3);
+    const c = a.neg();
+
+    try testing.expect(c.re == -5 and c.im == -3);
+}
+
+test "complex.mulbyi" {
+    const a = Complex(f32).init(5, 3);
+    const c = a.mulbyi();
+
+    try testing.expect(c.re == -3 and c.im == 5);
+}
+
 test "complex.reciprocal" {
     const a = Complex(f32).init(5, 3);
     const c = a.reciprocal();