Struggling to know how many slates you need for your project?

Why not let us do the work? Simply use our calculator or send us your dimensions and we’ll calculate how many slates you need.


Simple method you can use to calculate roof size!

If your property has hips and valley, like in the picture above, please get in contact so we can help you accurately calculate your roof size. On condition that your roof is a simple up and over, like the picture below, you can calculate it yourself.

Start by measuring the length of your building. Followed by the length of the ridge or, if you can not get access to your ridge, measure the width of the property instead (call us if this is the case). In this example the Length is 8 metres (800cm) and the ridge length is 4 metres (400cm). Simply multiply this figure together to get a square meterage of one side of your roof. In this case 8 x 4 =32Sqm as the roof has two sides simply multiple this figure by 2, 32 x 2 =64 Sqm is the total size of your roof.

To then calculate how many slates you will need simply check out our Slates sizes and Quantity Guide. You will ned to multiply your Sqm2 by the amount of slates per sqm2. For example if your roof is 64Sqm2 and you want to use 500x250mm slates then you would multiply 64 x 21 = 1,344 slates. Please note this doesn’t take in to consideration of skylights, chimney breasts, hips or Valleys which all will add to the quantity of slates needed. As they will need to be cut, we ALWAYS recommend adding a 10% wastage amount to your order to make sure you don’t run out.

If you want to make your life easier simply use our SLATE CALCULATOR TOOL

Our calculator will automatically work out the amount of slates, slate and halves and ridge tiles you will need specifically based on your location. It will recommend what size slate you can use and will give you the option to choose what size and what slate you prefer from our shop. Once in checkout, it will also calculate your delivery costs to your door. 



Slate calculator

Our Slate Calculator Tool does all the work for you! Simply enter your details and our calculator will determine what size slates are available to you, recommend slates from our shop and will even show you a report with all results and recommended headlap included.

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Slate Buyers Guide

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3 ways to calculate Roof pitch 

It’s essential to know what the Pitch of your roof is, check out this guide if you need help.

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