[Solved]-highchart total in tooltip-Highcharts

more easy, use total property of point:

tooltip: {
    formatter: function() {
        var s = '<b>'+ this.x +'</b>';
        $.each(this.points, function(i, point) {
            s += '<br/>'+ point.series.name +': '+ point.y;
        });
        s += '<br/>total: '+ this.points[0].total
        return s;
    },
    shared: true
},

check this reference

use the footerformat property (since version 2.2) with {point.total} to easily show the total without having to re-define the complete formatter function:

tooltip: {
    footerformat: 'sum: <b>{point.total}</b>',
    shared: true,
},

excatly, see example: http://jsfiddle.net/65bpvudh/7/

tooltip: {
    formatter: function() {
        var s = '<b>'+ this.x +'</b>',
            sum = 0;

        $.each(this.points, function(i, point) {
            s += '<br/>'+ point.series.name +': '+
                point.y +'m';
            sum += point.y;
        });

        s += '<br/>sum: '+sum

        return s;
    },
    shared: true
},