Simple count down timer problem

   //Timer2
 

void setup()
{
  Serial.begin(9600);
  Serial.println("Enter seconds to time");
}

void loop()
{
  
  timer();
}

void timer()
{
  
  
  if (Serial.available()> 0)
  {

      float timeInput = Serial.read(); // Take input from serial monitor.
  
  timeInput = timeInput - 48; // Todo: for some reason processor adds 48 to input, this corrects that.
  timeInput = timeInput * 1000;  //Converts time input to milliseconds.
    
      
      Serial.println(timeInput/1000);
      delay(timeInput); // Counts down to zero timeInput.
          
      
      
    
  Serial.println("Timer Done!");
   

  }
}

There are two problems I am having with this sketch. When I input a number of seconds to count down, the compiler adds 48 to it. Further, if I input a two digit number such as 12, it treats the 1 then the 2
as separate entries. The sketch does work for a single-digit entry. Thanks.

      float timeInput = Serial.read(); // Take input from serial monitor.

Serial.read() does not return a float.

When I input a number of seconds to count down, the compiler adds 48 to it.

No, it doesn't. It sends (assuming you are using the Serial Monitor) the value as a string. You are expecting the whole string to be read as a number. That doesn't happen. YOU have to read the string and convert it to a number.

Arduino take a sequence of number and treat every digit as its own digit. what you need is someway of telling the arduino that the sequence of number is not just a single digit thing but a whole.

i found out that sending a terminator help alot
maybe you could use a special character like "/" or "*" as to tell the arduino this is the end

like

while(Serial.read()!="/")
{
  int val=Serial.read;
  int Sum=Sum*10+val;
  }

the snippet does not work, but it should show you how it is done.

Thank you all. I will work on the string conversion.