Nether Portal Coordinate Calculator

Overworld and Nether coordinates share an 8:1 ratio — 1 Nether block equals 8 Overworld blocks. Going Overworld → Nether divides X and Z by 8; going Nether → Overworld multiplies them by 8. Y is untouched. Because the exact result can land inside a block rather than on its corner, the rounded value is the block most players actually stand on or build a portal near. Before creating a new portal, vanilla also searches a 128-block radius around the destination coordinate (measured in whichever dimension you're arriving in) for an existing one to link to, so you rarely need to be exact to the block.