I have got psd of 1800px width from my client that needs to be converted to HTML but my screens are of highest resolution 1366px only. what is best way to design this type of psds? Is there any tools available to change psd in 1366px or some way to increase screen size. so I can check for pixel perfect output.
You will simply have to zoom and pan, unless you want to invest in a better monitor.
Not directed at you: I find it somewhat hilarious that anyone would ever design a site at 1800px wide. To me that's a clear sign of someone that has little clue about real world usage.
I would output at full size and use width:100% and let the browser do the pixel perfect rendering. You can only control so much. If it's that rigid and cannot be scaled, center top left or something and work the design to it.