Why OBS records at the wrong size and how to fix it

OBS (Open Broadcaster Software) often records at a resolution that doesn't match what you see on your screen because the program defaults to 1920×1080 pixels, regardless of your actual monitor size. If your screen is smaller — say 1366×768 — or larger, the recording will either squeeze your content or leave black bars around it. The fix is to change your canvas resolution and output resolution to match your monitor's actual dimensions.

This matters because a mismatched resolution makes your recording harder to watch, wastes storage space, and can cause playback problems on different devices. Setting it correctly takes about two minutes and prevents hours of frustration later.

Key Takeaways

  • Find your monitor's actual resolution by right-clicking your desktop, selecting Display Settings, and reading the resolution listed under "Display resolution".
  • In OBS, go to Settings > Video and change Canvas Resolution to match your monitor, then change Output Resolution to the same number.
  • If you want to record at a smaller size to save storage space, set Output Resolution lower than Canvas Resolution, but never set Canvas Resolution lower than your actual monitor.
  • Test your settings by starting a 10-second recording, stopping it, and checking that the video fills your screen without black bars or stretching.

Find your monitor's actual resolution first

Before you open OBS, you need to know what resolution your screen actually is. On Windows, right-click anywhere on your desktop background and select Display Settings. Scroll down until you see "Display resolution" — it will show two numbers separated by an ×, like 1920×1080 or 1366×768. Write this number down.

On Mac, click the Apple menu in the top left, select System Settings, then click Displays in the left sidebar. Look for "Resolution" — you may need to click "Scaled" to see the actual pixel dimensions. The number you want is the one that says "Looks like" followed by a resolution.

If you have multiple monitors, check each one separately. OBS will record whichever monitor you tell it to, so you need the resolution of the one you plan to record from.

Set your canvas resolution in OBS

Open OBS and go to Settings (Windows) or Preferences (Mac) in the top menu. Click Video in the left sidebar. You will see two fields: Canvas Resolution and Output Resolution.

Canvas Resolution is the size of the workspace OBS sees. Set this to match your monitor exactly — if your monitor is 1366×768, type 1366 in the width field and 768 in the height field. Do not guess or round. If you are unsure which number is width and which is height, the larger number is almost always width.

After you change Canvas Resolution, click outside the field or press Enter to save it. OBS may ask you to confirm — click OK. Your preview window (the black area in the center of OBS) should now show the same proportions as your actual screen.

Set your output resolution to match

In the same Video settings window, find Output Resolution. For a straightforward recording that matches what you see, set this to the same number as your Canvas Resolution — 1366×768 if that is what you chose above.

Click outside the field to save. You can now close Settings and start recording. When you play back the video, it should fill your screen without black bars or distortion.

When to use a different output resolution

If you want to save storage space or upload to a platform that prefers a specific size, you can set Output Resolution lower than Canvas Resolution. For example, you could keep Canvas at 1366×768 but set Output to 1280×720. OBS will shrink the recording without changing what you see while recording.

Never set Output Resolution higher than Canvas Resolution — this will make the video blurry. Never set Canvas Resolution lower than your actual monitor size — this will crop your screen and you will miss parts of what you are trying to record.

If you record at a lower output resolution, test it first. Start a short recording, stop it, and play it back on the device where you plan to watch it. Some platforms automatically resize videos, so what looks small in your media player might look fine when uploaded.

Troubleshooting common problems

If your recording has black bars on the sides or top and bottom, your Canvas Resolution is wrong. Go back to Settings > Video and check that Canvas Resolution matches your monitor exactly. Close OBS completely and reopen it after you change it — sometimes the preview does not update until you restart.

If your recording looks stretched or squished, you may have set Canvas and Output to different aspect ratios. For example, 1920×1080 (wider) and 1280×960 (squarer) will not match. Stick to the same width-to-height ratio for both, or set Output to the same dimensions as Canvas.

If you are recording a specific window or process and it appears smaller than expected, check that you added the window as a source in OBS. The Canvas Resolution controls the overall recording size, but you still need to add what you want to record. Click the + button under Sources, select Window Capture, and choose your process.

Frequently Asked Questions

What if I don't know my monitor's resolution?

Right-click your desktop and open Display Settings (Windows) or System Settings > Displays (Mac). The resolution is listed clearly. If you see multiple options, pick the one marked as "Recommended" — that is your monitor's native resolution.

Can I record at 1920×1080 if my monitor is smaller?

Technically yes, but it will add black bars to your recording and waste storage space. OBS will stretch your smaller screen to fit 1920×1080, leaving empty space. Record at your actual resolution instead.

Why does my recording look different from what I see on screen?

Your Canvas and Output resolutions probably do not match your monitor. Go to Settings > Video and set Canvas Resolution to your actual monitor size. If you changed Output Resolution to something smaller, that is normal — the recording will be smaller but the proportions should stay the same.

Do I need to change these settings every time I open OBS?

No. OBS saves your settings automatically. Once you set Canvas and Output Resolution correctly, they stay that way until you change them again.

What if I have a laptop and an external monitor?

Check the resolution of whichever monitor you plan to record from. If you want to record your laptop screen, use your laptop's resolution. If you want to record the external monitor, use its resolution. You can only record one at a time, so set Canvas to match whichever one you are using.