Number Formatting at Highcharts Chart Values?

plotOptions.pie.dataLabels.formatter is a function that will let you format the label. In this case I returned this.percentage.toFixed(2) which will trim your number at 2 decimal places. Demo at this jsFiddle

plotOptions: {
    pie: {
        dataLabels: {
            formatter: function() {
                return '<b>' + this.point.name + '</b>: ' + this.percentage.toFixed(2) + ' %';
            }
        }
    }
},

tooltip: {
   pointFormat: "Value: {point.y:.2f}"
}

this is not for formating the values .

var data = [{
     name: 'Population',
     data: [],
     dataLabels: {
         enabled: true,
         rotation: -90,
         color: '#FFFFFF',
         align: 'right',
         x: 4,
         y: 10,
         style: {
             fontSize: '13px',
             fontFamily: 'Verdana, sans-serif',
             textShadow: '0 0 3px black'
         }, formatter: function() {
             return  Highcharts.numberFormat(this.y, 2, '.');
         }
     }
}];

the formart of the values can be change in the dataLables in the data .

We do have tooltip formatter options to display the value as number instead of percentage

http://api.highcharts.com/highstock#tooltip.formatter

tooltip: {
   formatter: function() {
      return '<b>'+ this.point.name +'</b>: '+ this.point.y ;
   }
},

this.point.y will do the trick (now you have this.percentage in that place)

You can just format it like this below.

    tooltip: {
    pointFormat: "Value: {point.y:.2f}"
}

documentation about Highcharts formatting