I need a way to resize any window (not just Firefox!) to specific sizes.

I need to check what the application I'm writing looks like at these resolutions - how many columns are visible in grids, that sort of thing.

I know I could just change my resolution, but that's a hassle, especially for 800x600 - desktop icons get smooshed together and stuff.

  • 2
    Still, changing the screen resolution also takes the taskbar into account. So, when only resizing application windows, then be sure to make it a bit smaller to account for the available screen estate.
    – Arjan
    Feb 9, 2011 at 11:37
  • @Arjan: for Chrome, several web extensions offer a way to exactly set the viewport. See f.ex. stackoverflow.com/questions/46998025/… (by me)
    – serv-inc
    Oct 29, 2017 at 14:16
  • @serv-inc, while true, that's not what this question is about.
    – Arjan
    Oct 29, 2017 at 14:50
  • VTR as this is easily phrased as a how do I achieve X, not necessarily a give me a program to X
    – bertieb
    Feb 14, 2018 at 23:21

8 Answers 8


Check out Sizer ...

Sizer is a tiny freeware utility that gives you an easy and fast way to resize any window to an exact size. It could be a very useful tool for webmasters and web designers.

  • Excellent! That's a very slick program. I hope it eventually supports vista/win7 but for now I'm still on XP anyway. Thanks :)
    – Blorgbeard
    Aug 4, 2009 at 22:16
  • I have it running under Vista on my main dev box at work without issue. Aug 4, 2009 at 22:38
  • @David Spillett: Curious - are you running Vista x86 or x64? Aug 4, 2009 at 23:41
  • 1
    Problem is there is no version for Windows 7 - 64 Bit :( i've used Sizer for years and now I can't.
    – user66766
    Feb 9, 2011 at 11:29
  • 1
    The 64bit version is currently under development, but available for download. Works on my machine(tm)
    – CGK
    Dec 13, 2011 at 22:46

You could write your own with AutoHotkey:

#=:: ; [Win]+[=]
    WinGet, window, ID, A
    InputBox, width, Resize, Width:, , 140, 130
    InputBox, height, Resize, Height:, , 140, 130
    WinMove, ahk_id %window%, , , , width, height


Before: 640 x 480


  1. Press Win+=.

  2. Enter a width:


  3. Enter a height:


After: 400 x 300


Note: To set a length to 0, you have to input 0. An empty value is ignored. For example, if you only want to resize the height, leave the width blank and enter a value for the height.

For the curious: 0 x 0


As you can see, a window with a title bar and controls has an absolute minimum size.

  • For those interested, Here is a similar approach to change one of the four (X,Y,width,height) of active window. autohotkey: how to resize window by both absolute and relative height
    – qeatzy
    Oct 18, 2017 at 11:30
  • 1
    I set a window in W10 to 960x540, but the result is 946x533. Do I need to add a value for the title bar and scrolling bar, so its more an inner dimension than an outer?
    – mgutt
    Jun 28, 2020 at 9:41
  • @mgutt Same for me. I've found that it can be worked around on a per-application basis with code such as the following just before the line WinMove: if WinActive("ahk_exe chrome.exe") { width += 16 height += 8 } Sep 20, 2020 at 15:00

I suggest WinSize2.

  • Simple, fast, and easy to manage by using Alt++ And Alt+- keys to increase/decrease the size of the current window.
  • Working on any Windows version, or at least I have tested it on Windows XP, 7 and 8.
  • Free Software.

When it comes to the latest versions of Windows 10 (2021) I had the best luck with Window Resizer

I always have 3 browser windows open and I prefer all of them to be the exact same size all over lapping each other spot on. Plus I greatly dislike having a ton of things running in the notification area. You can run this app, restore your windows then close the app.


I do not know if it was a coincidence, but right after installing SIZER my Windows interface totally malfunctioned - the start menu got transparent windows was not refreshing and I could not click anything. I had to disable transparency in Windows 10 to fix this. Did anyone have such an issue too?

I ended up using this : https://www.mindgems.com/article/resize-window-to-specific-size-set-window-size-in-pixels/

Actually, I am quite happy with it as it is really easy. If you press CTRL+SHIF+R on any window a dialog appears and you can enter the sizes that you want. The current size of the window is displayed too.

On top of that, you can capture and annotate screenshots too. Give it a try I am sure you will love it. I tested it on Windows 10 and 11 and it does the job perfectly.

enter image description here

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You can do that with the WS Grid+ Window Manager. It costs 4.99 EUR but there is a 7-days trial for you to test.

I am using it with Windows 11 and it works great:

WS Grid+ Window Manager


I like the AutoHotkey solution of @iglvzx, but the code posted only works in AutoHotkey v1. Here is working code for AutoHotkey v2:

#Requires AutoHotkey v2.0-

#=::resizeWindow(WinGetID("A")) ; [Win]+[=]

resizeWindow(window) {
    WinGetPos , , &W, &H, window
    width := InputBox("Width: " W "px", "Resize", "w100 h84", W - Mod(W, 4))
    if (width.Result = "OK") {
        height := InputBox("Height: " H "px", "Resize", "w100 h84", H - Mod(H, 4))
        if (height.Result = "OK") {
            WinMove , , width.Value, height.Value, window

Extra features in here: it shows the current width and height in the popups and suggested the next smaller value rounded to 4px. Adapt to your liking :-)


With powertoys fancy zones this can be achived pretty neatly. Define a fancyzone of the desired size by dragging. It shows the size in realtime so pretty easy. When the zone is defined and enabled, you can drag any window while holding shift will allow you to release the window in the zone you defined before and it will resize to fill the zone.

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