Set height of chart in Chart.js

If you disable the maintain aspect ratio in options then it uses the available height:

var chart = new Chart('blabla', {
    type: 'bar',
    data: {
    },
    options: {
        maintainAspectRatio: false,
    }
});

The easiest way is to create a container for the canvas and set its height:

<div style="height: 300px">
  <canvas id="chart"></canvas>
</div>

and set

options: {  
    responsive: true,
    maintainAspectRatio: false
}

You can wrap your canvas element in a parent div, relatively positioned, then give that div the height you want, setting maintainAspectRatio: false in your options

//HTML
<div id="canvasWrapper" style="position: relative; height: 80vh/500px/whatever">
<canvas id="chart"></canvas>
</div>

<script>
new Chart(somechart, {
options: {
    responsive: true,
    maintainAspectRatio: false

/*, your other options*/

}
});
</script>

This one worked for me:

I set the height from HTML

canvas#scoreLineToAll.ct-chart.tab-pane.active[height="200"]
canvas#scoreLineTo3Months.ct-chart.tab-pane[height="200"]
canvas#scoreLineToYear.ct-chart.tab-pane[height="200"]

Then I disabled to maintaining aspect ratio

options: {
  responsive: true,
  maintainAspectRatio: false,

You can also set the dimensions to the canvas

<canvas id="myChart" width="400" height="400"></canvas>

And then set the responsive options to false to always maintain the chart at the size specified.

options: {
    responsive: false,
}

I created a container and set it the desired height of the view port (depending on the number of charts or chart specific sizes):

.graph-container {
width: 100%;
height: 30vh;
}

To be dynamic to screen sizes I set the container as follows:

*Small media devices specific styles*/
@media screen and (max-width: 800px) {
.graph-container {
        display: block;
        float: none;
        width: 100%;
        margin-top: 0px;
        margin-right:0px;
        margin-left:0px;
        height: auto;
    }
}

Of course very important (as have been referred to numerous times) set the following option properties of your chart:

options:{
    maintainAspectRatio: false,
    responsive: true,
}

See, there is a mistake in the initializing statement. The maintainAspectRatio should come inside the options object as follows

...

options = {
   maintainAspectRatio: false,

 ...
}

...

Now, what you can do is set the height of the parent element of the chart, so here div .chart is the parent of div #myChart. So, specifying the height of div .chart should just work fine.

Consider the following code.

<div class="chart" style="height: 500px;">
   <canvas id="myChart"></canvas>
</div>

Change the height according to yourself, for me 500px just works fine ;)

He's right. If you want to stay with jQuery you could do this

var ctx = $('#myChart')[0];
ctx.height = 500;

or

var ctx = $('#myChart');
ctx.attr('height',500);

You should use html height attribute for the canvas element as:

<div class="chart">
    <canvas id="myChart" height="100"></canvas>
</div>

Set the aspectRatio property of the chart to 0 did the trick for me...

    var ctx = $('#myChart');

    ctx.height(500);

    var myChart = new Chart(ctx, {
        type: 'horizontalBar',
        data: {
            labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
            datasets: [{
                label: '# of Votes',
                data: [12, 19, 3, 5, 2, 3],
                backgroundColor: [
                    'rgba(255, 99, 132, 0.2)',
                    'rgba(54, 162, 235, 0.2)',
                    'rgba(255, 206, 86, 0.2)',
                    'rgba(75, 192, 192, 0.2)',
                    'rgba(153, 102, 255, 0.2)',
                    'rgba(255, 159, 64, 0.2)'
                ],
                borderColor: [
                    'rgba(255,99,132,1)',
                    'rgba(54, 162, 235, 1)',
                    'rgba(255, 206, 86, 1)',
                    'rgba(75, 192, 192, 1)',
                    'rgba(153, 102, 255, 1)',
                    'rgba(255, 159, 64, 1)'
                ],
                borderWidth: 1
            }]
        },
        maintainAspectRatio: false,
        options: {
            scales: {
                yAxes: [{
                    ticks: {
                        beginAtZero:true
                    }
                }]
            }
        }
    });
myChart.aspectRatio = 0;

Just to add on to the answer given by @numediaweb

In case you're banging your head against the wall because after following the instructions to set maintainAspectRatio=false: I originally copied my code from an example I got on a website on using Chart.js with Angular 2+:

        <div style="display: block">
          <canvas baseChart
                  [datasets]="chartData"
                  [labels]="chartLabels"
                  [options]="chartOptions"
                  [legend]="chartLegend"
                  [colors]="chartColors"
                  [chartType]="chartType">
          </canvas>
        </div>

To make this work correctly you must remove the embedded (and unnecessary) style="display: block" Instead define a class for the enclosing div, and define its height in CSS.

Once you do that, the chart should have responsive width but fixed height.

Needed the chart to fill the parent element 100%, rather than setting height manually, and the problem was to force parent div to always fill remaining space.

After setting responsive and ratio options (check out related chartjs doc), the following css did the trick:

html

<div class="panel">
  <div class="chart-container">
    <canvas id="chart"></canvas>
  </div>
</div>

scss:

.panel {
  display: flex;

  .chart-container {
    position: relative;
    flex-grow: 1;
    min-height: 0;
  }
}

I hope this is not late but will help someone.

var canvas = document.getElementById(id);
canvas.width = window.innerWidth;
canvas.height = window.innerHeight / 2.5;  
var ctx = canvas.getContext('2d');

Set the width and the height before you create the chart, adjust the height as you wish.

Setting the Size of a chartjs diagram can be simply achieved by setting the with of a surrounding container:

   <div style="width:400px;">
     <canvas id="myChart"></canvas>
   </div>

But an important detail is, that you may need to resize your diagram after creation:

var ctx = $('#myChart');
var myChart = new Chart(ctx, {
    ......
    data: {
           ........
    },
    options: {
        responsive: false,
        maintainAspectRatio: true
    }
});
// now resize the new chart to fit into the canvas....
myChart.resize();

The problem here is that maintainAspectRatio needs to be inside the options node, not at the same level as in the example.

Add one relative position element whose height is calculated from padding (works same as aspect ratio) but if you need that chart does not exceed certain maximum height then use new powerful min unit of css. Also add fixed fallback padding where this is not supported.

<div class="dashboard-charts" style="position: relative; padding-top:40%; padding-top:min(40%,530px)">
    <div style="position:absolute;width: 100%;height:100%;left: 0;top: 0">
        <canvas id="sales-dashboard-bar"></canvas>
    </div>
</div>

and then inside options object of javascript set maintainAspectRatio to false to consider and use parent element height which in this case is absolute positioned and sized relative to the grandparent's size.

var mychart = new Chart(document.getElementById("sales-dashboard-bar"),{
    options: {
        maintainAspectRatio: false,
    }
})

Thus chart will scale nicely with aspect ratio of 2.5 until it hits the maximum height which is 530px here and stops scaling afterwards.

You can keep this line in options: maintainAspectRatio: false

const ctx = document.getElementById('myChart');
  new Chart(ctx,    {
    type: 'doughnut',
    data: {
      labels: ['Red', 'Blue', 'Yellow', 'Green', 'Purple', 'Orange'],
      datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        borderWidth: 1,
      }]
    },
    options: {
         maintainAspectRatio: false,
         plugins: {
            title: {
                display: true,
                text: 'Location Based Alerts'
            },
             legend: {
                display: false,
                labels: {
                    color: 'rgb(255, 99, 132)'
                }
            },
        },
    }
  });

For react, doing this works:

<Doughnut
  data={data}
  height="200px"
  width="200px"
  options={{ maintainAspectRatio: false }}
/>