What size radiator
are you looking for?

Calculate The Right Radiator Size For You

Use our radiator size calculator to figure out which radiator is most suitable for you. Radiator sizes differ vastly depending on the style and variety of radiator you decide to opt for.

Stelrad has the largest range of radiator sizes in the UK, which is why our radiator size calculator is such a useful tool. Whether you decide on one of our Standard Radiator sizes or decide that one of our modern Designer Radiators is ideal for you, our radiator size chart will assist in helping you make your ultimate decision when you buy a radiator at Stelrad.

Radiator sizes and shapes at Stelrad are completely different depending on their functionality, their design and what room they belong in. Vertical Radiators have much different dimensions to Horizontal Radiators for example and a Bathroom Radiator such as a Towel Rail Radiator will differ vastly in shape and size from one of our Column Radiators.

Using our radiator sizing guide will help you make your decision, so when your new radiator arrives, you don’t get a shock when it gets stuck when you try to install it. Radiator sizes in the UK are measured in millimetres (mm), so it’s worth bearing in mind that when using a radiator size calculator in the UK, we like to measure in metric!

Radiator Size Calculator UK – FAQs

What Size Radiator Do I Need?

Using our radiator size calculator will assist in figuring out what dimensions your new radiator should be to accommodate your space and how to calculate radiator size for your room. Using our radiator sizing guide is great for the physical measurements, but another useful tool to help you calculate how much heat output is appropriate for your room is our BTU Calculator. This heat loss calculator will work hand in hand with our radiator size calculator for UK radiators and help create a radiator size chart that will direct you to which model of radiator is most suitable for your room.

What Size Radiator Do I Need For My Room?

What size radiator you need for your room will be dependent on the dimensions of it. If you are replacing an existing radiator and are wondering how to calculate radiator size for your room, follow these 4 simple steps:

  • Measure the height of where the radiator will be placed.
  • Measure how wide you need your radiator to be.
  • Measure the pipe centres (from the centre of the left-hand pipe inlet to the centre of the right)
  • Measure the wall to pipe centres (from the centre of the pipe inlet to the wall)

Are Radiators Standard Sizes?

Radiator sizes are not consistent over different models, due to their varying dimensions. For example, a Vertical Radiator will be much taller than it is wide than a Standard Radiator.

What Are Standard Radiator Sizes?

Standard radiator sizes at Stelrad are between 700mm x 1400m at the smallest, and 600mm x 2400mm at the largest.

Within the Standard Steel Panel Radiators range, the smallest is 700mm x 1800mm and the largest is 700mm x 2000m, whereas the largest vertical options is 1800mm x 600mm. “Standard” doesn’t mean one-size at Stelrad and the options are limitless!

How To Calculate Radiator Size For A Room?

Radiator sizes in the UK use the metric system for their measurements, so this is also important when measuring your room or using a radiator size calculator. If you’re comparing feet against metres, for example, the lack of consistency will leave your head in a spin, unless you’re some kind of maths whizz.

To calculate the BTU output accurately and effectively for a room, you will need to grab your tape measure and measure the height of your room, the width of your room, the length of your room and lastly, the size of the window area – the length x width of your window in m².

The reason for calculating the window dimensions is plain and simple – heat loves to escape. The bigger the window, the more chance of your heat escaping. This will also differ depending on whether you have single or double-glazed windows. Single glazed windows lose the most heat, so your BTU will need to be higher for these.

If you have any further questions and for all radiator FAQs, view our advice hub, we are always happy to help.

You still have items in your basket

Would you like to checkout?