Change the Y-axis values from real numbers to integers in Chart.js

Question

I have a chart that I want to include in my website using Chart.js. In the Y-axis, it gives me real numbers instead of integers. How can I change the number to integers?

Here's a picture of what I have now:

And this is the code:

var lineChartData = {

    labels : ["2013/04/01","2013/03/31", "2013/03/30", "2013/03/29", "2013/03/28","2013/03/27", "2013/03/26"],

    datasets : [
        {
            fillColor : "rgba(151,187,205,0.5)",
            strokeColor : "rgba(151,187,205,1)",
            pointColor : "rgba(151,187,205,1)",
            pointStrokeColor : "#fff",
            data : ["0", "2","1", "0", "1","0","1"]
        }
    ]

}

var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Bar(lineChartData);

Solution 1

Try this, where max is the highest value of your data.

var steps = 3;
new Chart(ctx).Bar(plotData, {
    scaleOverride: true,
    scaleSteps: steps,
    scaleStepWidth: Math.ceil(max / steps),
    scaleStartValue: 0
});

Solution 2

I handled it this way in new version:

new Chart(ctx, {
  type: 'bar',
  data: chartData,
  options: {
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true,
          callback: function(value) {if (value % 1 === 0) {return value;}}
        }
      }]
    }
  }
});

Solution 3

I wasn't able to get the existing answers to work for me when using the new version 2 of Chart.js, so here's what I found to solve this problem in V2:

new Chart(ctx, {type: 'bar', data: barChartData,
  options:{ 
    scales: {
      yAxes: [{
        ticks: {
          stepSize: 1
        }
      }]
    }
  }
});

Solution 4

I know this is an old question now, but in the current version (v2.9.3) you can just set the precision of the y-axis ticks to zero to get integers:

options: {  
    scales: {
        yAxes: [{
            ticks: {
                precision: 0
            }
        }]
    }
}

Solution 5

Check the Chart.js documentation, in the Global configuration section:

// Boolean - Whether the scale should stick to integers, not floats even if drawing space is there scaleIntegersOnly: true,

View more solutions

Comments

[Thomas Sebastian]

@Mewel I don't wan't the y-axis labels to be displayed at all. How could I do that? There has to be an option right.

[Thomas Sebastian]

I found it. If anyone wants to remove the labels entirely you can add scaleShowLabels: false to your option attribute.

[Gavin]

If it doesn't work you probably didn't have scaleOverride: true.

[apfz]

please be aware that this will show all integers in your y-axis. if your graph is running from 0 to 300, all the 301 integers and grid lines will be shown.

[DBS]

@apfz Very true, this only works well when you have a good idea of your data's scale, and can work out a reasonable step size in advance.

[Jibu James]

Thanks a lot mate! Worked like a charm. I wonder why this isn't the top answer.

[John]

Probably chart version 1, that's outdated

[xandermonkey]

This is a great answer. It's worth noting that the same can be done with the tooltips

[Wal Heredia]

I'd like to suggest this code as solution. That works perfectly!

[Klaymen]

This should be the accepted answer, as this needs no additional considerations (finding the maximum, declaring steps, etc.)

[Alejandro]

This shows a compilation error when using typescript, the property don't seems to be declared.

[Faheem]

Those facing type issues. Rename "yAxes" to "y" and it should be an object not an array.

[Nick BL]

Also just used this and it seemed to be the right way to go for those finding this post later. (not using typescript though so i cannot comment on that)

[SNS Web]

Set stepSize: 1 -> work perfectly on v3.8.0, keep in mind i have this doubt : autoSkip: false, // false -> show all labels (not reduced by Chart.js) but ... stepSize : 1, // ignored if autoSkip == true ?

[Soundtemple]

Thanks. beginAtZero: true is what I needed.