Inkscape > (Photoshop | Illustrator) <3
Here is my personal web design template I created for Inkscape.
It's based on Bootstrap's grid system and contains 12 columns, each spaced 78.33333 pixels apart.
I created the template with a width of 1366px. Why? Because this is the most popular screen size.
1st Guide: (1366 - 940) / 2 = 213
2nd Guide: 213 + 78.33333 = 291.33333
3rd Guide: 291.33333 + 78.33333 = 369.66666
4th Guide: 369.66666 + 78.33333 = 447.99999
5th Guide: 447.99999 + 78.33333 = 526.33332
6th Guide: 526.33332 + 78.33333 = 604.66665
7th Guide: 604.66665 + 78.33333 = 682.99998
8th Guide: 682.99998 + 78.33333 = 761.33331
9th Guide: 761.33331 + 78.33333 = 839.66664
10th Guide: 839.66664 + 78.33333 = 917.99997
11th Guide: 917.99997 + 78.33333 = 996.33333
12th Guide: 996.33333 + 78.33333 = 1074.66667
13th Guide: 1074.66667 + 78.33333 = 1152.99996