1)<br> If [this][1] was your reference tool, then the correct EPSG would be EPSG:3006, i.e., **SWEREF 99 TM**. This is (further) confirmed using the official [Control Points][2] <br> <br> 2) It also appears that your "flat Easting coordinate" value i.e., *1677500* looks off. Perhaps the correct value was *677500*? <br> <br> 3) Using 6589150N and 677500E, the results are as below. [![enter image description here][3]][3] [![enter image description here][4]][4] ---------- Reply to comment from Questioner >*Question perspective your are right, but I actual problem is values of X and Y. >It should be interchanged and value 1677500->167750* The [SWEREF 99 web tool][1] uses X for (N)orthing or Latitude, and Y for (E)asting or longitude. This is a rather unfortunate choice, although not technically incorrect, because most software, including proj4.js, use X for longitude and Y for latitude. If your Easting is 167750, then it won't compute. You can try it yourself in the [SWEREF 99 web tool][1]. And 1677500 appears "out of bound". [1]: https://www.lantmateriet.se/sv/Sjalvservice/enkel-koordinattransformation/ [2]: https://www.lantmateriet.se/contentassets/a7ddfc3b7821498da8b55cd3f71b5150/kontrollpunkter_sweref99tm.pdf [3]: https://i.sstatic.net/EXpI9.jpg [4]: https://i.sstatic.net/Sj3ke.jpg