How Retrosizer Simulates Retro Games on Handheld Screens

Retrosizer simulates retro game systems on handheld screens by rendering each classic system's native resolution at accurate pixel scaling inside a to-scale model of the device's display. You see how a Game Boy, GBA, NES, SNES, Genesis/Mega Drive, or PlayStation image actually fits on a given screen — including the letterboxing or stretching that comes with mismatched aspect ratios — before you buy the device.

What the simulation actually shows

The tool places two things side by side in one visual space:

• The device itself, drawn at true relative scale so you can drag, rotate, and arrange handhelds next to each other.
• The screen content, a simulation of how a specific retro system appears on that device's display.

Because both the hardware outline and the on-screen image are scaled to the same reference, the comparison is spatial rather than numerical. You are not reading a spec sheet of resolutions; you are looking at how big the game image is and how much unused screen surrounds it.

The pixel scaling mechanism

Each retro system has a fixed native resolution and a fixed pixel aspect ratio. Retrosizer maps that native output onto the target device's panel using accurate pixel scaling, which means:

1. Integer or near-integer scaling keeps pixels crisp instead of blurring them, so the simulated image reflects what a good emulator setup would actually produce.
2. Aspect ratio handling determines whether the image fills the screen, sits in a bordered box, or gets stretched. A Game Boy title on a wide modern panel will not fill the width the way a native widescreen game would.
3. Relative screen size is preserved, so a small device with a high-resolution panel and a large device with a low-resolution panel look genuinely different rather than being normalized to the same box.

The practical result: the simulation answers "how much of this screen does the game use, and how sharp is it?" rather than just "what resolution is the panel?"

Systems and devices covered

The screen simulations cover Game Boy, Game Boy Advance, NES, SNES, Genesis/Mega Drive, PlayStation, and others. Supported hardware spans a wide range of manufacturers, including:

This range matters because the same retro system can look completely different across a 1-inch FunKey S, a 4-inch RG-35XX, and a 7-inch Steam Deck.

How to use it for a buying decision

1. Pick the devices you are choosing between and place them next to each other. The relative scale immediately shows size differences that photos hide.
2. Select the retro system you care about most — for example, GBA if that is your library, or SNES if you want 4:3 content.
3. Look at the screen simulation, not just the device outline. Check how much of the panel the game uses and whether the image looks uncomfortably small or letterboxed.
4. Rotate and rearrange to test different orientations, since some handhelds are used vertically for certain systems.
5. Share the comparison via URL if you want to revisit it or ask someone else's opinion.

Where the simulation helps most

The clearest use case is a device with a panel shape that does not match classic systems. A wide screen may be great for PSP and PlayStation content but leave large black bars for Game Boy and SNES. Conversely, a 4:3 panel suits most 8-bit and 16-bit systems but wastes space on widescreen-native content. Seeing the pixel-scaled image at true relative size makes that trade-off concrete instead of theoretical.

A second use case is judging whether a small device is actually usable for text-heavy games. A system that looks fine on a large handheld can render uncomfortably small on a compact one, and the simulation shows that directly.

Limits to keep in mind

The simulation reflects screen geometry and pixel scaling, not emulator performance, input latency, or build quality. It also does not tell you whether a specific device runs a given system well — only how the image would appear. Use it to settle the visual question, then check performance and ergonomics separately.