Binary string to decimal

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _13.BinaryToDecimal
{
    class BinaryToDecimal
    {
        static void Main()
        {
            Console.Write("Enter a binary numbes as string: ");
            string binary = Console.ReadLine();
            int digit = 0;
            int power = 0;
            long sum = 0L;
            for (int i = binary.Length - 1; i >= 0; i--)
            {
                digit = binary[i] - '0';
                double temp = Math.Pow(2, power);
                sum += (int)temp * digit;
                power++;
            }
            Console.WriteLine(sum);
        }
    }
}