1 column:
150px / 1000px
= 15%

1 column:
150px / 1000px
= 15%

1 column:
150px / 1000px
= 15%

1 column:
150px / 1000px
= 15%

1 column:
150px / 1000px
= 15%

1 column:
150px / 1000px
= 15%

2 columns:
320px / 1000px
= 32%

2 columns:
320px / 1000px
= 32%

2 columns:
320px / 1000px
= 32%

3 columns:
490px / 1000px
= 49%

3 columns:
490px / 1000px
= 49%

6 columns:
1000px / 1000px
= 100%

A live demo to show the benefits of adapting a fluid design from a 1000px grid.