Converting KB to MB, GB, TB dynamically

public String size(int size){
    String hrSize = "";
    int k = size;
    double m = size/1024;
    double g = size/1048576;
    double t = size/1073741824;

    DecimalFormat dec = new DecimalFormat("0.00");

    if (k>0)
    {

        hrSize = dec.format(k).concat("KB");

    }
    if (m>0)
    {

        hrSize = dec.format(m).concat("MB");
    }
    if (g>0)
    {

        hrSize = dec.format(g).concat("GB");
    }
    if (t>0)
    {

        hrSize = dec.format(t).concat("TB");
    }

    return hrSize;
    }

This is a method that should return size in GB,MB, KB or TB. Input value is in KB. for example result for 1245 should be like 1.21MB but what I get is 1.00MB.