Getting 2 decimals instead of 1 with f1.

 public class CurrencyConverter : MonoBehaviour {
 
     private static CurrencyConverter instance;
     public static CurrencyConverter Instance{
         get{
             return instance;
         }
     }
 
     void Awake()
     {
         CreateInstance ();
     }
 
     void CreateInstance()
     {
         if(instance == null)
         {
             instance = this;
         }
     }
 
     public string GetCurrencyIntoString(float valueToConvert, bool currencyPerSec, bool currencyPerClick)
     {
         string converted;
         if(valueToConvert >= 1000000)
         {
             converted = (valueToConvert / 1000000f).ToString("f1") + " M";
         }else if(valueToConvert >= 1000)
         {
             converted = (valueToConvert / 1000f).ToString ("f1") + " K";
         }else
         {
             converted = "" + valueToConvert;
         }
 
         if(currencyPerSec == true)
         {
             converted = converted + " sps";
         }
 
         if(currencyPerClick == true)
         {
             converted = converted + " spc";
         }
         return converted;
     }
 
 }
 

I am pretty new to c# so please give easy explanation if possible. Thanks.

I'm using this code for a per second tick. I want to get say "1.1" but instead im getting "1.10" and it sometimes get stuck with a 9 on the end that just stays there.