Fixing Stretched or Wrong Aspect Ratio in Emulators
Characters look too wide, too thin, or the image doesn't fill the screen correctly. This almost always traces to a pixel-aspect-ratio setting, not the emulator core rendering incorrectly.
Stretched, squashed, or oddly-proportioned graphics in an emulator almost always trace to an aspect ratio setting mismatch, not a rendering bug in the core itself — this is a genuinely common point of confusion because the “correct” aspect ratio for classic systems is less obvious than it first appears.
Step 1: understand why this is confusing in the first place
Many classic systems’ native pixel resolution (for example, 256×224) doesn’t have the same width-to-height ratio as a standard 4:3 or 16:9 display — because these systems were designed for CRT televisions, which didn’t display “square” pixels the way a modern digital display does. The “correct” aspect ratio for a given system is the ratio it was designed to be displayed at on a period-accurate CRT, not simply the raw ratio of its native pixel resolution.
Step 2: check the frontend’s current aspect ratio setting
RetroArch: Settings → Video → Scaling → Aspect RatioCommon options include Core Provided (uses the value the core itself reports as correct for that system), Full (stretches to fill the entire display window, ignoring proportions), and specific fixed ratios like 4:3 or 16:9.
Step 3: set aspect ratio to “Core Provided” as a sensible default
Settings → Video → Scaling → Aspect Ratio: Core ProvidedMost cores correctly report the historically-accurate aspect ratio for the system they emulate — this setting defers to that value rather than requiring you to know the correct ratio for every individual system yourself.
Step 4: check for Integer Scale interacting with aspect ratio settings
Settings → Video → Output → Integer ScaleInteger scaling and a fixed aspect ratio setting can sometimes conflict, particularly at window sizes that don’t divide evenly — if the image looks correct proportionally but has odd letterboxing or doesn’t fill the window as expected, try toggling this setting to see which combination looks right for your specific display size.
Step 5: check for a per-content override that’s not what you expect
Quick Menu → Overrides → check for an existing per-game
or per-core aspect ratio override that might be
conflicting with the global setting.A previously-set per-game override persists even after changing the global setting, and can be the reason a specific game looks wrong while the global setting otherwise works correctly for everything else.
Step 6: check for a custom aspect ratio value entered incorrectly
Settings → Video → Scaling → Aspect Ratio: Config
→ Custom Aspect Ratio (X Position, Y Position,
Width, Height)If a custom ratio was configured manually at some point (rather than using Core Provided or a standard preset), a typo or miscalculation here directly produces exactly this kind of stretching — reverting to Core Provided rules this out entirely.
Step 7: understand that “matches the original hardware” and “looks square/undistorted to a modern eye” are different goals
Some players deliberately choose a non-historically-accurate aspect ratio because square pixels look more natural on a modern flat display — this is a legitimate preference, not a “wrong” configuration, as long as it’s a deliberate choice rather than an accidental misconfiguration you didn’t intend.
Why “Core Provided” is the right default rather than something to second-guess
Core authors generally research and encode the historically correct aspect ratio for the specific system they’re emulating — second-guessing this with a manually-configured custom ratio, without a specific, deliberate reason to do so, is a common way this exact stretching problem gets introduced in the first place. Reverting to Core Provided is usually the fastest fix precisely because it removes a manual configuration step that didn’t need to exist.