What is an equirectangular image?

A sphere, flattened

A 360° camera captures the entire sphere of light around it: every compass direction plus straight up and straight down. Image files are flat, so the sphere has to be unrolled. The equirectangular projection does it the simplest possible way: longitude (the compass direction, 0° to 360°) becomes the horizontal axis and latitude (from −90° at the floor to +90° at the sky) becomes the vertical axis, with every degree given the same number of pixels.

That is why the image is always 2:1: 360 degrees across, 180 degrees down. It is the same projection as the classic rectangular world map, with the same side effect: the poles are stretched across the whole width. The single point of sky directly above the camera becomes the entire top edge of the photo, which is what gives an equirectangular image its melted look when viewed flat.

A 360° viewer reverses the process. It maps the rectangle onto the inside of a sphere, places the camera at the centre, and shows only the part you are facing. The stretching cancels out exactly, and you see the scene as if you were standing there. Try it with the free viewer: the sample photo looks like a smeared strip in a normal image app and like a room in the viewer.

Where equirectangular photos come from

• 360° cameras: Insta360 X-series and ONE series, Ricoh Theta, GoPro Max, Trisio, Kandao QooCam, Labpano. Most stitch two fisheye lenses into an equirectangular JPEG in the camera or its app; see the guides for Insta360, Ricoh Theta and GoPro Max.
• Phone apps: the Google Street View app and Cardboard Camera capture full spheres by guiding you through a series of shots. The built-in panorama mode on iPhone and Android captures only a horizontal strip, not a full sphere.
• 3D rendering: Blender, 3ds Max with V-Ray or Corona, Unreal Engine, Unity, Twinmotion, Enscape and Lumion all have an equirectangular or "spherical panorama" camera for architectural visualisation.
• AI and games: skybox generators and text-to-panorama models output equirectangular images because every game engine and viewer already understands the format.
• Stitching software: PTGui, Hugin and Autopano assemble a full sphere from dozens of DSLR shots on a panoramic head.

How to tell if a file is equirectangular

1. Check the dimensions. The width should be exactly twice the height: 5760×2880, 6080×3040, 8192×4096, 11968×5984. A 3:1 or 4:1 image is a strip panorama; a square image is usually a stereoscopic top/bottom pair.
2. Look at the top and bottom edges. In a true equirectangular photo the sky and floor are smeared into horizontal bands that touch the edges; a stitched strip panorama has a normal-looking sky.
3. Check the metadata. Cameras write XMP "GPano" tags such as ProjectionType=equirectangular and FullPanoWidthPixels. Facebook and Google Photos use these to decide whether to show a photo as 360°.
4. Open it in a viewer. If the free viewer shows a coherent room with a straight horizon, it is equirectangular. If the horizon bends or the scene shows two circles, it is not.

Common problems and fixes

• Two circles side by side: the file is an unstitched dual-fisheye capture (Insta360 .insp, GoPro Max .jpg). Export it from the camera's app to get the stitched equirectangular version.
• Looks stretched or bends at the edges: the image is a partial panorama. The viewer wraps whatever it is given around the full sphere; a strip that covers 120° gets stretched to 360°. Shoot with a 360° camera or a full-sphere app instead.
• Mirrored text: the image was exported flipped, or a viewer applied the texture to the outside of the sphere. Flip it horizontally in any editor.
• Visible seam or tilted horizon: re-stitch with the camera app's horizon-levelling option, or rotate the image in software such as Insta360 Studio or PTGui.
• Appears in 3D when it is not: a square image is treated as a stereoscopic pair. Toggle 3D top/bottom off in the viewer.
• Blurry when zoomed in: the file was downscaled for the GPU (phones cap at 8K or 4K textures) or was exported at low resolution. Export at the camera's full size and view on a desktop for maximum detail.

Equirectangular vs. other 360° formats

Equirectangular is the interchange format, but it is not the only way to store a sphere. Cubemaps split the sphere into six square faces and are common inside game engines and some tour platforms because they waste fewer pixels at the poles. Dual fisheye is what the camera sensors actually record before stitching. Little planet (stereographic) images are a creative re-projection for social media, not a source format. Most tools convert between these; a viewer only ever needs the equirectangular version.

Stereoscopic 360° photos store two equirectangular images, one per eye, stacked top and bottom (or occasionally side by side) in a single file. They deliver depth in a VR headset, and the free viewer detects the top/bottom layout automatically.

Frequently asked questions

Try it now

Everything above works in the viewer on this site: pick a 360° photo, look around, step into VR, export a video or grab an embed code. Photos never leave your browser.