How do you find the centre of a circle or round shape? We explain.

Finding the centre of a circle can be important for various purposes. For example, it is useful when you want to mill a hole in the circle or determine where the table leg should be mounted. We give various tips for determining the centre of a circle or oval!

Can you mark the centre of the circle?

We get the question more and more often: 'Can you mark the middle of the circle?' Because we use a CNC machine, you get a cool circle without marking in the middle. But don't worry, you can easily do this yourself with our tips!

Are you looking for a tightly milled circle or oval? Order them quickly and easily online.

Bestel direct een cirkel of ovaal op maat

What do you need?

In order to perform this task well, it is important to have:

  • A pencil
  • Yardstick or tape measure
  • Possibly a (large) sheet of paper or a geodesic.
  • and of course the circle (or oval).

Have you got these products ready? Then let's get to work on determining the centre point!

Method 1: Fast and efficient!

The first method may not be the most accurate, but in many cases it is useful. Place the circle in front of you and take the ruler. First measure the widest point of the circle, then put the ruler back on the circle and place dots at half the widest point. Do this from different angles so that you can later connect these points, as it were.

Method 2: Measure accurately!

This method allows you to measure the centre point more precisely than the previous method. However, this method is a little more complicated when you are working with a large dimension.

  1. Place the circle in front of you, on a flat surface.
  2. Take the tape measure and pick out a certain length. Does your circle have a diameter of 30.0 cm, just like ours? Then take two points at 20,0 cm. See figure 1 below. Mark 0,0 cm and 20,0 cm with a dot.
    Tip: do not take the first part of the ruler, as this can sometimes differ from reality by a few millimetres.
  3. Now take a sheet of paper, in this case an A4, and place it against the two marked points. In this case, the A4 is a tool to check yourself for an angle of 90° degrees. You can also use a geodesic triangle or any other tool with a 90° degree angle.
  4. Run your tape measure along the A4 'down'. Mark the point where the A4 meets the end of the circle.
  5. Repeat this process on the other side.
  6. Take the tape measure or the sheet of paper and now connect the opposite points, so that a cross is formed.
  7. The centre of the cross is the diameter.

Tips for marking the centre of an oval

Measuring the diameter of an oval works in much the same way as above. Take two points that are symmetrically connected and make sure that they are connected again at right angles, so that you can simply draw a cross.

Any other tips? Let us know about it!

These are two ways to find the centre of a circle or oval. Of course, there are more tips for measuring a diameter, if you know of a good tip that really can't be missed in this blog post? Send us an email with explanations and possibly pictures. We are always open to new insights and hope to be able to help our visitors even better.

View our range