I want increase font size of label that appears on hover in chart.js,I am trying to give custom text to label but am not able to increase it's font.
 var myPieChart = new Chart(ctxP, {
                            type: 'pie',
                            data: {
                                labels: datas.labels,
                                datasets: [{
                                    label: 'Dataset 1',
                                    data: datas.value,
                                    backgroundColor: datas.colour
                                }],
                                others: datas.others
                            },
                            options: {
                                hover: {
                                    mode:'index'
                                },
                                legend: {
                                    display: true,
                                    position: "right",
                                    "labels": {
                                        "fontSize": 20,
                                    }
                                },
                                tooltips: {
                                    "fontSize": 20, bodyFont:20,
                                    callbacks: {                                       
                                        label: function (tooltipItem, data) {
                                            let label = data.labels[tooltipItem.index];
                                            let value = data.datasets[tooltipItem.datasetIndex].data[tooltipItem.index];
                                            let otherdata = data.others[tooltipItem.index];
                                            return ' ' + label + ': ' + value + '%  ' + otherdata;
                                        }
                                    }
                                }, hover: {
                                    mode: 'index',
                                    "label": {
                                        "fontSize": 20,
                                    }
                                }
                            }
                        })

i tried hover: {                  mode: 'index', "label": { "fontSize": 20, } } but it didn't work
this is how it looks right now

To increase the font size of label that appears on hover in chart.js
To change the font size of tooltips in Chart.js 3.x, just use options.plugins.tooltip.titleFont.size or options.plugins.tooltip.bodyFont.size.


let ctxP=document.getElementById('mychart').getContext('2d');
let datas={
    value: [10, 15, 20, 25],
    labels: ['A', 'B', 'C', 'D']
};
var myPieChart=new Chart(ctxP, {
    type: 'pie',
    data: {
        labels: datas.labels,
        datasets: [{
            label: 'Dataset 1',
            data: datas.value,
            backgroundColor: datas.colour
        }],
        others: datas.others
    },
    options: {
        hover: {
            mode: 'index'
        },
        legend: {
            display: true,
            position: "right",
            "labels": {
                "fontSize": 20,
            }
        },
        tooltips: {
            // "fontSize": 20, bodyFont: 20,
            callbacks: {
                label: function (tooltipItem, data) {
                    let label=data.labels[tooltipItem.index];
                    let value=data.datasets[tooltipItem.datasetIndex].data[tooltipItem.index];
                    let otherdata=data.others[tooltipItem.index];
                    return ' '+label+': '+value+'%  '+otherdata;
                }
            }
        },
        hover: {
            mode: 'index',
            "label": {
                "fontSize": 20,
            }
        },
        plugins: {
            tooltip: {
                titleFont: {
                    size: 20
                },
                bodyFont: {
                    size: 20
                }
            }
        }
    }
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.9.1/chart.min.js"></script>
<canvas id="mychart"></canvas>



