How to measure for a replacement entry door

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How to measure for a new (or replacement) door

There are three ways to measure a door: measure the existing door (if it fits well in the frame), measure inside the door frame, or measure the door opening brick to brick.

Measuring a front door or internal door for replacement is pretty easy. Measuring a door opening without a frame is a little more complicated, but still relatively straightforward.

The rule to remember is, always err on the bigger side because you can sand down, but you can’t add it back on.

If your door is too small or loose it could rattle in the frame and will have gusty draughts around the edge. Taking time to get the perfect fit makes a big difference in energy efficiency.

To hang a wooden door, a skilled joiner is needed to ensure the door sits straight in the frame.

For composite or uPVC doors, these usually come as a complete doorset built with the frame for a perfect fit with door and frame.

Measuring for a doorset is the same as measuring for a door opening without a frame below.

It’s always better to use a reputable installer that will take responsibility for the measurements. At Everest, we take all measurements for our doorsets and guarantee a perfect fit for your door without any rattling draughts.

Do you measure a door from the inside or outside?

When measuring the door, you can measure from the interior or the exterior as they are both the same.

There are three ways to measure a door:

• Measure the existing door (if it fits well in the frame)
• Measure inside the door frame
• Measure the door opening brick to brick

Measuring doors is a little different to windows because you can measure the actual existing door if you have it. Whereas you should never measure an existing window frame.

Take your measurements in metric millimetres and use a metal tape measure.

Measure the door width

• Start by measuring the width inside the door frame from door jamb to door jamb.
• Make sure you hold the tape measure taut and that you are measuring across in a straight line.
• Measure at the top and bottom, and in the middle.
• Compare the measurements and use the biggest measure.

Measure the door height

• Next measure the height of the door inside the frame. Start from where the floor level is going to be or the existing sill up to the underside of the door frame lintel.
• Measure the left side and then the right side.
• It is possible, the measurements could be different for each side if the door or frame isn’t straight.
• Take the biggest measurement and use that for the door height. Once the door is fitted it will be planed and sanded to fit.

Measuring a door opening without a frame

If you have an opening without a frame, or if you are measuring for a new doorset you need to measure the full opening where the door and frame will sit.

To get the correct measurement, the tape measure must be set against the edge of the brick opening and measured to opposite brick across the opening. Brick to brick in a straight line.

Once you have that measurement you will need to factor in how wide the door frame will be and deduct that from your measurements.

Speak to your manufacturer to get guidance on the required depth for the frame.

As mentioned at the beginning, when measuring a door, it’s always better to go slightly over size rather than under, so you have tolerance to sand the door down.

Consider your floor covering

If you are fitting a door before a new floor covering has been added, allow for the new floor height. That could be more or less than what you have already.

Make sure to factor the differences for a new floor into measurements before you buy your new door.

Is it time for a new front door?

Made-to-measure for a perfect fit

Everest entrance doors are made to measure for a perfect fit. We use a product-specific trim around the door frame for a neater finish and to keep the cold air out and heat in.

DOORS

JB Kind understand that it can be quite a job to source the right door size for your requirements, we know that shopping around for the perfect door and ending up with an ill-fitting door size is not what anyone wants. Follow our guide on how to measure up for a new door size to make sure that you don’t end up with a product that isn’t ideal for your situation. 

Please note that if you are buying replacement doors, DO NOT measure the existing door. You must always base your measurements on the door frame. There is an old craftsman’s expression, “measure twice, cut once”, so please bear this in mind. 

Another aspect to keep in mind when recording door measurements is the way the door opens. Stand in front of the door, so that it opens away from you, and take a note as to whether the hinges are on the right or left side of the door. Left side hinges mean the door is left-hand open away, whereas right side hinges mean the door is right-hand open away.

Step 1: Measure the door width

Take three measurements inside the door frame – at the top, middle and bottom. The widest measurement determines the width of the door.

• Use a tape measure to understand the width of the three areas of the door frame. Run the tape measure along the width of the frame from the left to the right and record these numbers.
• The standard UK widths of doors are: 24 inches/610 mm, 27 inches/686 mm, 30 inches/762 mm, 33 inches/838 mm.

Step 2: Measure the door height

Measure the inside of each vertical side of the frame. The longest length determines the height required. Remember to make allowance for any floor covering.

• Use a tape measure to understand the height of the door frame. Run the tape from the top corner to the bottom corner on each side and record the number of the longest length.
• Remember to take into consideration that this could be a job where you will need to stand on something like a chair to reach the top of the frame, it might be an idea to make sure a family member or friend is helping you when you take these measurements.
• The standard UK height of doors is most commonly 6’6”/1981mm but some may also be 2040mm.

Step 3: Measure the door thickness

If you are looking to purchase replacement doors and to keep the same frames, you will need to replicate the door thickness, so make sure to take this measurement also.

• Use a tape measure to understand the thickness of the existing door. Run the tape measure along the edge of the door and record the measurement of the thickness.
• You should also measure the rebate in the frame, where the door sits when closed.
• The recording of both measurements should be a close match and fit with one of the UK standard door thicknesses: 35 mm is the most common, but some doors may also be 40mm. NB. 45mm thickness usually refers to fire doors.

For a more detailed breakdown of the most common door sizes read our explanation on UK standard door sizes.  If you have non-standard door size requirements, please contact us, as bespoke sizes can be made to order for some of our door ranges. 

Can you replace an entry door without replacing the frame?

How do I know what size door to buy?