solving my Grid with sass? - layout

Question

I have been trying to solve my grid and I'm not sure why my columns are not stacking up next to each other. when I am making a div with a container and inside it a row and then 12 columns the columns are taking the full width then staking below
$screen-width: 1147px;
$number-of-columns: 12;
$gutter: 30px;
$column-width: $screen-width/$number-of-columns;
$padding: $gutter / 2;
$total-width: ($column-width * $number-of-columns) + ($gutter * ($number-of-columns - 1));
$gutter-width:($gutter / $total-width) * 100%;
#for $i from 1 through $number-of-columns {
.column-#{$i} {
width: ( $i /$number-of-columns ) * 100%;
background:#ccc;
float: left;
margin-left: $gutter;
}
}
#mixin clearfix() {
&:before,
&:after {
content: " "; // 1
display: table; // 2
}
&:after {
clear: both;
}
}
// Set Base Container
.container {
max-width:$total-width;
margin:0px auto;
padding: 0 $padding 0 $padding;
background: blue;
#include clearfix;
}
.row {
width: 100%;
margin: 0;
background: green;
#include clearfix;
}

Answer 1

You are dividing the available space by the number of columns, but then you are adding a margin to the left of each column So if you have 10 columns then each column is 10% of the total width + gutters. This adds up to more than 100% and is pushing three of your columns onto the next line.
Most grid systems solve this in one of two ways...
A) use css calc() to calculate the width of each column by dividing the space by the number of columns then deducting the gutter. E.g. calc(10% - 30px);
B) Use padding on each column to create the gutters and add it equally on both sides. E.g. padding:0 15px; This will give you an even spread of the columns and require no calculations but the downside is you'll need -15px margin on each side of your container to accommodate it and you'll need an extra HTML tag inside each column.

Answer 2

So I have managed to add that into a function, But now I have left margin what seems to be happening, which I'm not sure why is that, I have tried, things like putting a negative margin on the row.
$screen-width: 2147px;
$number-of-columns: 12;
$gutter: 30px;
$column-width: $screen-width/$number-of-columns;
$padding: $gutter / 2;
$total-width: ($column-width * $number-of-columns) + ($gutter * ($number-of-columns - 1));
$gutter-width:($gutter / $total-width) * 100%;
#function grid-width($cols, $has-gutter:false) {
#if $has-gutter {
#return calc(((100% / #{$number-of-columns}) * #{$cols}) - #{$gutter});
}
#else {
#return calc((100% / #{$number-of-columns}) * #{$cols});
}
}
#for $i from 1 through $number-of-columns {
.column-#{$i} {
width: grid-width(#{$i}, true);
background:#ccc;
display: inline-block;
margin-left: $gutter;
float: left;
}
}
#mixin clearfix() {
&:before,
&:after {
content: " "; // 1
display: table; // 2
}
&:after {
clear: both;
}
}
// Set Base Container
.container {
max-width:$total-width;
margin: 0px auto;
height:100px;
background: blue;
#include clearfix;
}
.row {
width: 100%;
height:50px;
background: green;
#include clearfix;
}