diff --git a/math/sqrt_double.cpp b/math/sqrt_double.cpp
new file mode 100644
index 000000000..e3418bfc3
--- /dev/null
+++ b/math/sqrt_double.cpp
@@ -0,0 +1,36 @@
+#include <iostream>
+#include <cassert>
+
+/* Calculate the square root of any 
+number in O(logn) time, 
+with precision fixed */
+
+double Sqrt(double x) {
+    double l = 0, r = x;
+    /* Epsilon is the precision. 
+    A great precision is 
+    between 1e-7 and 1e-12.
+    double epsilon = 1e-12;
+    */
+    double epsilon = 1e-12;
+    while ( l <= r ) {
+        double mid = (l + r) / 2;
+        if ( mid * mid > x ) {
+            r = mid;
+        } else {
+            if ( x - mid * mid < epsilon ) {
+                return mid;
+            }
+            l = mid;
+        }
+    }
+    return -1;
+}
+int main() {
+  double n{};
+  std::cin >> n;
+  assert(n >= 0);
+  // Change this line for a better precision
+  std::cout.precision(12);
+  std::cout << std::fixed << Sqrt(n);
+}