Calculate the length from the roller shutter belt


Many blinds are operated manually via a belt. If this roller shutter belt breaks, a new one must be bought. But before you buy, there is an important question: how long must the new roller shutter belt be? There are different ways to determine the length. We show you how to calculate a roller blind belt in length.

Calculation methods for roller shutter belt length

There are things you hardly ever mind about. The length of the roller shutter is such a matter. Only when the belt breaks and a new belt has to be bought, the question arises, how long the new belt must be. To size the length, you can use different methods:

  • rule of thumb
  • measure the old belt

Measure the old belt

Most of the belt is so torn yes and a direct measurement is not possible. The easiest way is when the belt is first removed. Then the two pieces of belt are measured with a cord or a rope. Just take the cord or the rope and lay it lengthwise on the broken strap. Of course, you must consider both belt parts.

Calculate the belt according to a rule of thumb

But in order to be able to measure the belt so, of course, it must first be removed once. This brings us back to the point that you may have to work twice. So to disassemble everything to measure the strap, then again the whole procedure to renew the old, cracked roller shutter belt. In particular, if a belt is to be replaced because you choose a new color, it is really double the effort, if not everything can remain disassembled, as long as there is no new belt.

Calculating the strap length from the roller shutter

In this case, you can use a rule of thumb to calculate the strap length. You can do this differently. That is, there are two variants of this rule of thumb:

  • Window height times 2 plus half the window height
  • Window height times 2 plus 1 m

In principle, they are with both formulas on the right side, which should be expected with an additional meter rather on doors such as balcony doors. They measure the window from the window sill to the lintel. So not the pure window surface. Now take this value either times 2.5 or 2 times plus 1. Then you have the required length. By way of example, this looks like this:

  • Window height 1.50 m by 2.5 is 3.75 m
  • Balcony door height 2.20 m by 2 is 4.40 plus 1 m equals 5.40 m

Now you have each calculated the appropriate belt length for the corresponding shutter. The double length corresponds to the rolling on the roller shutter shaft in the roller shutter box or the retractor in or on the wall inside. The additional need is for fastening plus a sufficient tolerance.

Tips & Tricks

The house journal offers you numerous guides and instructions. Here you can also read about how to repair the roller shutter belt.


Video Board: Roll Diameter Calculator / Durchmesser Rollen Rechner