Seamless Texture Tiling Previewer
A texture that looks fine alone can show ugly seams when repeated. Upload it, tile it and shift by half to find the problem.
A seamless texture looks continuous when repeated. Shift by half and look for lines or repeats in the middle.
Upload a texture to preview tiling.
When to use it
Checking a texture before you buy or download it
Tile the preview image and see whether the pack's floor or wall texture really repeats cleanly.
Large floors and terrain
A texture repeated across a big floor shows patterns from far away; tile it 6x6 to see what the player will see.
Fixing your own textures
The half offset puts the seam in the middle of the image, where you can paint over it.
Go further
Questions
Offset the image by half in an image editor, paint over the seams, then offset back. Check again here.
Strong details like a single stain or crack repeat noticeably. Remove them or add variation with decals.
Use Offset (GIMP: Layer > Transform > Offset, Photoshop: Filter > Other > Offset) by half the width and height, clone-stamp the seam in the centre, then offset back.
Mix two textures with a noise mask, add decals such as cracks and stains, or rotate and scale the UVs slightly between objects.