Portable projectors promise a 100-inch picture from something the size of a soda can. They can deliver that, in a dark room. Whether one is worth buying depends on reading three numbers correctly: brightness, resolution and battery.
Brightness is where the marketing gets creative. ANSI lumens and ISO lumens are standardized measurements taken across the image, and they are comparable to each other. "LED lumens," "light source lumens" and bare "lumens" with no standard named are not, and they can be several times higher than what reaches the wall. If a listing will not name the standard, assume the number is inflated.
Even standardized ratings are ceilings. XGIMI rates its MoGo 3 Pro at 450 ISO lumens, and a ProjectorCentral review measured about 330 ANSI lumens in its most accurate picture mode. That is normal, not a scandal, but it shows how far a spec sheet can sit from real use.
For context, 200 to 450 lumens is fine for a screen of 60 to 80 inches with the lights off. It will look washed out in a lit room or outdoors before sunset.
Resolution is simpler. Check the native resolution. Many cheap projectors "support 4K" only in the sense that they accept a 4K signal and scale it down to 720p or less. At this size, native 1080p is the level worth paying for.
Battery life is shorter than people assume. Anker's Nebula Capsule 3, listed at $429, is rated for 200 ANSI lumens and up to 2.5 hours of video, which covers one movie. Some models skip the internal battery entirely. The MoGo 3 Pro has none, and portable use means a power bank or XGIMI's $129 PowerBase stand. Also note that brightness often drops in battery mode.
Sound is the other compromise. Built-in speakers are fine for a bedroom, but outdoors you will want a Bluetooth speaker.
The short version: a portable projector is worth it if you want a big picture in a dark room and like moving it around. Compare ANSI or ISO lumens only, insist on native 1080p, and treat battery claims as one movie at best. For a living room with windows, a TV is still the better buy.
