Balustrade stair parts calculator

  Stair calculator banner  

Revamping your stairs can instantly enhance and add value to your home, but sometimes it's hard to know where to start. This is where our balustrade calculator can help. Designed for use with the Immix and Fusion spindle and glass panel collections, the calculator will show you the stair components required and how much they would cost. All you have to do is enter a few measurements and choose which staircase banisters you prefer.

      Shop for Staircase Parts      

What does the calculator do?


The Wonkee Donkee balustrade calculator will work out what stair parts you need to replace your existing banister, and give an instant price. 

The tool is simple to use, and you can go back at any time to alter your choices and get a feel for how the stairs will look with different materials and components. Not only will the staircase image change each time you enter a new parameter, but the price will also update automatically.

The calculator will even save you money. If your existing newel posts can be cut down and used as newel bases, you have the option of indicating this so newel bases won't be included in the list.
In the case of the Fusion system, the calculator will tell you if you have enough handrail left over to use for a newel post, reducing the number of newel posts accordingly. Fusion newel posts and handrails are identical except for length!

Because the tool continually recalculates the price whenever you change any of the specifications, you can easily experiment with different designs and materials to keep on top of the costs involved as you go along, helping you to stick to your stair refurbishment budget.

  Stair calculator  
  The calculator offers a valuable safety feature as well. To protect small children, today's building regulations state that a staircase must not allow a 100mm sphere to pass through (narrower than a baby's head). This means that spindles, glass panels and newel posts cannot be placed more than 99mm apart. The balustrade calculator will take this into account when you enter your staircase measurements, and automatically adjust the number of components required.  

Which ranges does the calculator support?

  Fusion metal spindles  

You can currently use the calculator for the contemporary Fusion and Immix stair part collections.

The Fusion range offers a choice of pine and white oak handrails, newel posts and baserails.

Two types of metal spindle are available within the Fusion range:

MK1 spindles , the more cost-effective option, consist of plated mild steel tubes which are attached to the handrail and baserail with tough but flexible plated ABS plastic brackets.

MK2 spindles are made from stainless steel tube, and zinc alloy brackets that are able to swivel to accommodate the angle of the stairs.

MK1 and MK2 spindles are supplied with a quality chrome or brushed nickel plated finish.

To view the differences between the two types of spindles, click here.


The Immix range, available as over the post  and post to post styles, is made of white oak and is designed to be installed with the minimum amount of effort. You can use either glass panels or oak spindles for the balustrade, together with contemporary gun metal connectors. 

Both the baserails and handrails come with pre-cut slots for the glass panels, while the wooden spindles have their own unique connectors.

At present the balustrade calculator can only be used for the glass panel option. Based on your measurements it will work out how many panels you need for the stairs, as well as the landing if this is also required. 

Because the Fusion and Immix glass panel width is fixed at 200mm, there will be some shorter lengths of balustrading that cannot be accommodated. The calculator will let you know if the length you enter is not compatible with your chosen staircase system.

There will be alternative balustrade infill options open to you, such as mixing with spindles or using a custom glass panel. Please feel free to contact us on 01938 557733 for advice.

  Immix balustrade  
    Immix - over the post  


  Fusion stairs rising to landing  

The calculator will ask whether you want a balustrade for the stairs only, landing only or for stairs and landing combined. 

The main landing is obviously where your stairs emerge at the top - usually the first floor of the house. A landing can also be an intermediate platform situated between floor levels to connect flights of stairs. It may consist of a quarter landing (the width of one flight of stairs) which gives a 90 degree turn, or a half landing (the width of two flights of stairs) resulting in a turn of 180 degrees. 

Whichever type of landing you have, if it is exposed to one side you will need a balustrade to comply with building regulations.

The calculator will currently work with straight landings at the top of the stairs only. If you have a landing with a turn, you may be able to treat it as one complete length, adding a right hand horizontal turn, a left hand horizontal turn or an adjustable landing connector. Check that the quantity of landing spindles or glass landing panels is sufficient for your needs. 



Normally there will be a newel post located at the bottom and top of the staircase. If the length of your banister or handrail is greater than 2.4m, you will need to install an additional newel, known as an intermediate newel.

The calculator is designed to be used with the majority of straight stairs only. It cannot calculate for stair parts required with winder stairs or stairs that have an intermediate landing, or stairs with  a change in direction. The calculator can still be used by breaking up each section as individual stairs, but you will need to check the total handrail langth required, and the total number of newels and newel connectors required. 


Newel distance


If you need a landing balustrade you'll be asked for the landing newel distance. This is the measurement (in millimetres) between the inside faces of the newel posts on the landing, or between the landing newel post and the wall. Newels are upright supports that hold the handrails.

You may also need to enter the stair newel distance, which involves measuring the stairs between the inside faces of the bottom and top newel posts. For maximum accuracy, measure along the string (the long piece of supporting timber found on each side of the staircase) and hold the tape measure at the same angle as the stairs. Aim for as accurate a measurement as possible. Try to get someone to help you with this if possible.

As for the width of the newel posts, the balustrade calculator will automatically assume that this is 90mm unless you enter your own measurement.

  Measuring newel post distance  

Stair pitch

  Stair angle measurement  

The final measurement needed is the pitch, or angle, of your staircase so that the tool can work out how many spindles or glass panels are required.

The easiest way to do this is to download a mobile app. Search for Inclinometer, Clinometer or Tiltmeter and choose the one most suited to your type of phone or tablet. Many of these apps are free. Make sure you check its accuracy first by checking on a known horizontal and vertical surface using a spirit level.

Alternatively, you might prefer to use an electronic inclinometer or a good old-fashioned protractor. Tips on using a protractor can be found in our installation guides - just visit the Fusion or Immix product pages and click on the fitting instructions at the side. The calculator offers options for Immix stair angles of between 40° and 45°, and Fusion stair pitches from 38° to 42°.


Reviewing your balustrade


Click next to view the following page. Here you will see a list of all the parts needed for your stair balustrade along with the price of each item.

The components will usually include a wooden handrail and metal endcap, a baserail, newel post, newel cap and connectors.

You may also see rake glass panels and rake connectors on the list. The term 'rake' refers to the pitch of the stairway.

If your staircase banisters include the landing, the list will also feature landing spindles or glass landing panels, top and bottom handrail connectors, a landing connector and, usually, a wall connector.

Clicking on each product in the list will bring up its picture, so you can see exactly what you're getting.

The total cost of the balustrade both with and without VAT is given at the bottom of the page.

  Balustrade calculator review page  

At this stage you can either choose to go back and modify your stair design, or add the list of stair parts to your basket. On the next page you can decide whether to begin a new stair design, visit the online stair parts shop to find any other items you may need, or go to your basket to finalise the purchase of your stair balustrade components. 


Checking out

  Stair parts  

When you arrive at your basket you will find a list of all the stair parts and their prices, quantities required and the final total both excluding and including VAT. Each stair product has a link back to the shop page so you can read all the details about it before going ahead.  

When it comes to payment there are two choices. The Quick Checkout button allows you to simply enter your delivery address and payment details. However, you will not be able to view or store your order history, or save your payment information and delivery address to use for any future purchases. 

The second option is to register as a customer. This will let you save invoice and delivery addresses, view your order history and check out more quickly next time. It's also a reliable way of recording exactly which stairparts you bought, including sizes and product codes, which can be extremely useful if you need to replace any in years to come.


Installation Calculator


Once your new stair components have arrived, you can use our Stair Balustrade Installation Calculator to work out exactly where to position them on the staircase during the fitting process.

This is essentially the same calculator, but instead of displaying a list of stair parts, the calculator tells you where to place the brackets of your glass panels or spindles. Remember to mark all these positions lightly, and check them for accuracy before any cutting or drilling takes place.

Links to the calculator are provided on our fitting instructions pages for both the Fusion and Immix ranges, along with diagrams and detailed advice on how to carry out the various measurements to ensure maximum accuracy.

We take you through the whole process of measuring the distance between newel posts, calculating the pitch of the staircase and marking out the positions of the balusters and glass panels. Taking time to get all these measurements right at this stage will help you achieve a professional finish. 

  Stair installation calculator  
      Shop for Staircase Parts