How Do You Trim a Door?

Posted: 3 Jul, 2025.

A door that sticks, scrapes along the floor or won’t close properly can be a daily nuisance. Whether it’s due to changes in flooring, swelling from humidity or a slightly oversized fit, trimming a door is often a simple and effective solution.

In this guide, we’ll take you through when and why an internal door might need trimming, the tools you’ll need and how to carry out each step safely and accurately for a smooth, professional-looking result.

When might it be necessary to trim a door?

Trimming a door is often necessary to maintain both its appearance and proper function. There are a number of reasons why you might need to trim a door.

For example, over time, changes in temperature and humidity can cause doors to swell or warp, which can make them difficult to open or close smoothly. In addition, during renovations or when installing new flooring, the clearance between the door and floor might change, which could result in trimming being required to stop the door from scraping.

Sometimes doors come slightly oversized from the manufacturer and will need adjusting to fit standard-sized frames. Trimming also helps improve ventilation or accommodate new hardware.

Trimming tolerances and structural integrity

It’s important to remember that not all doors can be trimmed the same amount. Each door will have a trimming tolerance, which is the maximum amount that can be removed from the edges without exposing the central core or weakening the joints. Over-trimming can compromise the door’s structural integrity, which can make it unusable.

To avoid this, you can check where the door was made or purchased and contact the manufacturer or supplier for guidance on safe trimming limits. This will ensure you don’t accidentally damage the door while trying to improve its fit.

Tools and materials you’ll need

Before you start trimming your door, you should gather all the tools you might need. Below is a handy list of the basic tools and materials required:

Tape measure
Pencil or marking tool
Straight edge or ruler
Handsaw or circular saw (depending on the type and thickness of the door)
Sandpaper or sanding block
Clamps
Workbench or sawhorses
Safety equipment (such as safety goggles and a dust mask to protect yourself)

Step-by-step guide to trimming a door

Trimming a door may seem daunting, but by following a clear, methodical process, you can achieve a professional finish.

Measure the door

It’s crucial to accurately measure the door when trimming it, to ensure a perfect fit. Taking your time at this stage helps avoid costly mistakes later on.

Start by using a tape measure to determine how much material needs to be removed, whether from the bottom, sides or top of the door. You’ll need to measure the gap between the door and the frame or floor, taking into account any flooring or thresholds that might affect clearance. It’s best to measure at a few different points along the edge to check for unevenness. Mark these measurements clearly with a pencil, as they will guide your cutting lines.

Remove the door

You can then remove the door from its hinges using a screwdriver, and lay it flat on a stable surface such as a workbench or sawhorses. You should make sure the door is well supported to prevent any movement while cutting.

Next, you can remove any hardware, like handles or locks, that might get in the way. Then, clean the edges and surface to ensure you can precisely mark the door.

Mark the trimming line

The next step is to mark the trimming line on the door. Use a pencil and a straight edge or ruler to draw a clear, straight line along the area you need to trim. Make sure the line is visible but not too thick, as this will guide your cut. You can double-check the measurements before marking to avoid any errors. If you’re trimming more than one edge, you should label each line clearly to prevent confusion during cutting.

Choose the right cutting method

The best cutting method will depend on the type of door and the material you’re working with. For wooden doors, a handsaw or circular saw will usually provide clean, precise cuts. A circular saw is faster and better for longer, straight cuts, whilst a handsaw offers more control for smaller adjustments.

For hollow-core or composite doors, a fine-toothed saw works best to avoid damaging the surface. If you’re trimming just a small amount, a plane or sanding block might be sufficient.

You should always consider safety and the tools you’re most comfortable using to achieve a neat finish.

Make the cut

With your door securely supported and trimming line clearly marked, it’s time to make the cut. Make sure you’re wearing your safety goggles and a dust mask before you start.

Use the chosen saw to follow the marked line carefully, taking your time to ensure a straight and even cut. If you’re using a circular saw, you should clamp a straight edge guide to the door to help maintain accuracy. For handsaws, you’ll need to use steady, controlled strokes.

You should take your time and avoid rushing, as uneven cuts will affect the door’s fit and appearance.

Finishing touches

After trimming the door, you can inspect the cut edge for any roughness or splinters. Use sandpaper or a sanding block to smooth it out, working along the grain for a clean finish.

If the door is painted or varnished, you can touch up the cut edge to match the rest of the surface and protect it from moisture or wear.

You can then reattach any removed hardware and refit the door into the frame, checking that it opens and closes smoothly.

When to call a professional

While trimming a door is a task many homeowners can handle, there are situations where it’s best to call in a professional. If the door is particularly valuable, made from solid hardwood, or a fire door, any mistakes could be costly or compromise safety.

You should also consider professional help if you’re unsure about using power tools, don’t have the right equipment or if the trimming involves more complex adjustments, such as planing warped areas or resizing glazed doors. A professional will ensure the job is done accurately and without damage.

JB Kind has a huge range of interior doors in a variety of styles, colours, and finishes. Download our brochure or contact us to find out more.