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DIY Window Trim

Adding DIY window trim to windows in a room is one of the most easiest, fastest, and affordable ways to add beautiful character to a room.

I’m super excited to show you how to trim a window with a beautiful, classic style trim!

We’ve been working on transforming our living room into a cozy, stylish space that we love. Windows can really be a great architectural focal point in a room, so they are worth updating!

Painted DIY window trim with bamboo blinds

The original builder grade windows in our living room were significantly lacking any kind of wow factor or character:

boring builder grade windows before adding custom window trim

But now, they look awesome!

Double windows transformed with DIY window trim

This isn’t the first time we’ve completed DIY window trim. In our last house, I showed how we updated window trim by removing the old trim and adding a simple farmhouse style window trim. Although, I really like that style, this time around I wanted to do a super timeless, character filled window trim style. And I LOVE it!!!

Another big difference between our window trim in this tutorial and my previous tutorial on installing window trim is that this time around we totally replaced the window sill with a custom cut window sill. Check out the tutorial and video below for details!

Also, two other types of window trim we have installed are DIY window trim between windows which is a great detail to add for two or three windows next to each other, as well as this simple and quick DIY window trim on a budget!


Note, this post contains some affiliate links. For more info see my disclosures here.

DIY Window Trim



  • (4) 1x4s @ 8ft and (1) 1×4 @ 6ft***
  • (4) 1x2s @ 8ft and (1) 1×2 @ 6ft
  • (1) 1×6 @ 8ft (for window sills)
  • (1) 1×3 @ 8ft (for bottom of window trim)
  • (1) stop window molding @ 8ft (for bottom of window trim)
  • 2″ brad nails
  • Spackle
  • Primer
  • Paintable Caulk
  • Paint (I used Simply White by Benjamin Moore in Semi-Gloss)


Note: The bamboo blinds in these photos can be found HERE!

***Note, the amount of wood you will need depends on the measurements of your window. I’ve listed the amount of wood that I used for my two 60″ tall x 31″ wide windows. Make sure to pick straight boards!

1. Remove old window sill and trim

Since my original window sill was really short on the edges and not wide enough for side window trim, I had to remove it.

Remove the old window sill and trim by first scoring the caulk line edges with a utility knife or similar tool.

Removing old window sill by starting with utility knife to score the the caulk line edges

Then, pry it up and off with a prybar and hammer.

Remove old window sill with hammer and prybar

Removing old window sill

If you don’t want to replace your window sill, check out my simple and quick DIY window trim for a similar style that skips this step!

2. Create new window sill

For the new window sill, I used a 1×6 board which was deep enough for my window and extended out about 2 1/4″ past my window wall frame. Make sure to measure your current window sill depth to ensure a 1×6 will fit as well.

Measure the width of your window opening and add 10 1/2″ as we need 5 1/4″ overhang on each side. Using a miter saw, cut your 1×6 board to size for your new window sill. My window opening measures 31″ so I cut my 1×6 board to 41 1/2″ long.

Next, to create the L shape cut out for the window sill, mark 5 1/4″ in from each side of the board.

To create the L shape cut out for the window sill, mark 5 1/4" in from side of board

Then, measure the depth of the old window sill cut and mark that measurement perpendicular to the first mark to create the L shape cut out marks. Make sure to measure the depth on each side of the old window sill as it may vary from one side to the other.

measuring old window sill for new window sill cuts

new window sill board marked for cutting

Use a dremel tool or jig saw and cut out the L shape out of the wood to create the two window sill edges.

cutting new window sill edges with Dremel tool for DIY window trim

There was still some wood in the corner of our cut out which we used a chisel to remove.

chiseling window sill edges

3. Install the new window sill

Put the new window sill in place and make sure it fits. It’s ok if there is a little bit of a gap between the wood and wall as the small gaps will be caulked.

installing new window sill

Secure the window sill with 2″ brad nails and a brad nailer.

installing new window sill with brad nailer

4. Add the 1×4 DIY window trim to the window sides and top

Measure the length of the window frame opening on both sides. Cut the 1x4s to size for these side pieces. Then, install them on the left and right side of the window with brad nails.Add the 1x4 DIY window trim to the window sides

Now measure the distance from the end of the left 1×4 to the end of the right 1×4 and cut another 1×4 piece to this size to create the top window trim. Secure in place with brad nails. Note, we had to use a screw into the stud on the right side of the top board since the wall area was uneven.

Add the 1x4 DIY window trim to the window top

5. Add the 1×2 trim to the window sides and top

Repeat the steps in step 4 above, except make your measurements for around the 1x4s. When installing the 1x2s next to the 1x4s, turn the 1×2 pieces on their sides and secure the brad nails through them into the 1x4s instead of the wall.

This is the same method I used for our simple and quick DIY window trim too, it’s such a classic look!

use a brad nailer for side 1x2 window trim installation

how to trim a window with wood

6. Add the base window trim pieces

Measure the distance from the left 1×2 piece edge to the right 1×2 edge. Cut the 1×3 and stop window molding piece to this size. Install the 1×3 first, centered under the window sill, then install the stop window molding piece on top.

Note, we cut our base pieces a little too short as you can see in the photo below, but we did it correctly for our 2nd window.

Base trim added below window

Now the window is fully trimmed out and should look similar to this:

DIY window trim added to window and ready for paint

7. Caulk, fill holes, prime, and paint!

Alrighty, last step! Caulk all the gaps and seams. Fill the nail holes (and any wood knot holes) with a lightweight spackle, allow it to dry, then lightly sand those fillings so they are smooth.

These are the same finish steps we used for our other style of DIY window trim and when we added trim between windows on our three window makeover.

Next, prime the wood. Add a second coat of primer over the wood knots. Finally, add 2-3 coats of paint and you are all finished!!!

how to trim a window

How awesome does this DIY window trim look?! I absolutely love it, it’s so classic and has totally transformed our living room wall, giving the space so much character and coziness! I just sit on the couch and stare at it ha!

I hope this how to trim a window tutorial was easy to follow and helps you with your own window transformation! I’d love to see photos of your project! Feel free to share with me on Instagram and Facebook!


DIY Window Trim

DIY Window Trim

Yield: 1
Prep Time: 10 minutes
Active Time: 1 hour
Total Time: 1 hour 10 minutes
Difficulty: Easy

How to trim a window. This DIY window trim is one of the easiest, fastest, and affordable ways to add character to a room. It's perfect for adding craftsman style window trim to your windows


  • 1x4s @ 8ft
  • 1x2s @ 8ft
  • 1×6 (for window sill)
  • 1×3 (for bottom of window trim)
  • Stop window molding (for bottom of window trim)
  • 2″ brad nails
  • Spackle
  • Primer
  • Paintable Caulk
  • Paint


  • Utility Knife
  • Prybar
  • Hammer
  • Miter saw
  • Dremel tool or Jig Saw
  • Chisel (optional)
  • Brad nailer
  • Tape Measure
  • Paint Brush and Rollers


  1. Remove old window sill and trim using utility knife to score edges, followed by a prybar and hammer.
  2. Create a new window sill with a 1x6 board cut with a miter saw and with 10.5" more length than the old window sill. Use a Dremel or Jig saw to to cut the window sill edges in L shape using old sill as a guide. Use a chisel to remove extra wood.
  3. Install the new window sill with 2"brad nails and brad nailer.
  4. Cut the 1x4s to size and add the 1×4 window trim to the window sides and top using a brad nailer.
  5. Add the 1x2s to the sides and top of the 1x4 trim pieces with brad nails and a brad nailer. Make sure to turn the 1×2 pieces on their sides and secure the brad nails through them into the 1x4s instead of the wall.
  6. Add the base window trim under the new window sill using a 1x3 and stop window molding piece cut to size. Secure with brad nails.
  7. Caulk all seams and gaps around the window trim.
  8. Fill nail holes in with a light spackle.
  9. Add one coat of primer and then two coats of paint to window trim.


*The amount of wood you will need depends on the measurements of your window.

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Monday 21st of February 2022

Hello, Does the 1”x3” board sit flat below the stop window molding? Hard to tell from the pic. Thank you. Daniel


Friday 5th of January 2024

@Angela Marie Made, I love your blog. I am struggling with my old home as the previous owner replaced the windows with vinyl windows and I have about 3/4 inch to mount blinds which isn't enough for anything I have researched. I prefer not to do top mount. Would this new trim potentially help with my issue or do you have other ideas?

Angela Marie Made

Wednesday 23rd of February 2022


Lucy Middleton

Saturday 2nd of October 2021

Hi! Love this style of window trim! I have two questions, first as I was preparing to do this I went to the store and bought pine wood which as labeled 1x3 but in reality it measures 0.75 x 2.5. Is that normal? Also I have windows that are closer together, there’s a 9 in space between them. Should I treat it as one whole window or two individual window? I got stuck there because idk if I have enough room if I made them individual windows with the window sill at the bottom.

Looking forward to hear back! Lucy

Angela Marie Made

Wednesday 6th of October 2021

Thanks for reaching out!! The wood dimensions are the industry standard, I have a blog post that explains it better here: As for the space issue, you may want to see if you can modify the dimensions so that there is more room in between, I don't think it would look right if you treated it all as one but I could be wrong.


Friday 14th of August 2020

Hey Angela,

I’m going to be doing this on a few windows this weekend as I love the look! Do you know what color gray the walls are in your pictures? I really like the contrast

Angela Marie Made

Friday 14th of August 2020

Thank you, the walls are painted in Classic Grey by Benjamin Moore.


Wednesday 5th of August 2020

Are there benefits of wood vs drywall return or is it just a personal preference? We have custom shades coming in so I want to case the windows without affecting the interior width.

Angela Marie Made

Wednesday 5th of August 2020

Wood vs drywall returns are a personal preference, wood returns are typically more expensive to do and have a more traditional style look. Most homes in the past 20 years or so have been built using drywall returns and it is more common now. If you are considering adding wood returns, it will affect the interior width for your custom shades. You can still add wood trim like we did in our video without it affecting the interior width.


Saturday 13th of June 2020

Do your windows have drywall returns or are they wood case? I want to do this with my windows at home but I feel like adding wood casing is beyond my expertise. I'm concerned that adding just trim around the window and leaving the drywall returns may not look right. I can't tell from your video if you left the drywall returns, if you did then I will go for it because these look amazing!


Thursday 23rd of July 2020

Hi Sara. I replied to your question below. Hope it helps.



Thursday 23rd of July 2020

Hi Sara,

The interior window sides and top are drywall in this picture. These pictures look fantastic.

Like you, I prefer wood. However, they did a great job with these windows given the space limitations.

If you look closely, these windows have virtually no space between the glass window edge and the sill walls. They only way they could install wood casing along the sides and top would be to rip out the drywall along the sides and top. (This is actually very quick and easy.) However, I think this was a great compromise, especially with the windows trim painted white.

And regarding your concern about your ability to install wood along the sides and top of the interior window well, YOU CAN DO IT! It really is no more difficult than the sides.

The only challenge you will have is the dept of the well. Say it's 5 inches deep. You will have to rip saw the three boards (two sides, one top) to that depth. But, EVEN THAT is EASY! You can buy 1x6 boards at Lowe's or Home Depot for about $6 each. And then ask them to cut them. Make sure they cut them a little short (like 1/8th inch on the depth). That way, you can just caulk the gap.

I've rehabbed/sold many houses. And done probably thousands of feet of trim. If you follow this tutorial, YOU CAN DO IT!!

Best of luck. Thomas, Seattle, Wash., USA

Angela Marie Made

Monday 15th of June 2020

Thanks! We have drywall returns and we left them as is and just added the wood trim. Then, we caulked all gaps and painted both the same trim color so it looks cohesive.

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