When we create tables in LaTeX, the table column width will be automatically decided based on the content in the table cell. Sometimes, maybe we are not satisfied with the default column width and want to customize the column width. In this post, we will explain how to it in LaTeX.

Our initial table is like the following:

The code to produce this table is:

Click to show the code.
\documentclass{article}
\usepackage{booktabs}
\usepackage{multirow}

\begin{document}

\begin{table}[t]
    \centering
    \begin{tabular}{llll}
        \toprule
        \multirow{2}{*}{Country} & \multicolumn{2}{c}{GDP} & Change \\
        \cmidrule{2-3} \\
        {} & 2010 & 2015 & {} \\
        \midrule
        United States & 14964.400 & 18036.650 & 20.53\% \\
        China & 5812.464 & 11226.186 & 93.14\% \\
        Japan & 5793.455 & 4382.420 & -24.36\% \\
        Germany & 3309.668 & 3365.293 & 1.68\% \\
        United Kingdom & 2246.079 & 2863.304 & 27.48\% \\
        \bottomrule
    \end{tabular}
\end{table}

\end{document}

Column type with width parameter

Column width of the produced table is small. To control the column width, we need to use another three column types p, m, b:

Column type Description
p{width} Create fixed width column with top alignment
m{width} Create fixed width column with middle alignment
b{width} Create fixed width column with bottom alignment

The width parameter can be absolute value, like 2cm, 20pt etc. It can also be a relative value, e.g., 0.2\textwidth. Using relative width is preferred since the table width are often measured relative to \textwidth.

Table cell horizontal alignment

The above three column types only specify the vertical alignment of table column cell. To specify the horizontal alignment of table cell, we need to use the following three command provided by the array package:

Alignment Description
\centering Center alignment
\raggedright Left alignment
\raggedleft Right alignment

To add the alignment command to each cell, thus adjusting the column cell horizontal alignment, we use the following syntax before the table column type declaration:

>{some_command}

This will ensure that some_command is inserted before every column cell content.

Table with wider column and custom alignment

To use bigger column width and center alignment in first and last column in the above table, we can use the following code:

Click to show the code.
\documentclass{article}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{array}

\begin{document}

\begin{table}[t]
    \centering
    \begin{tabular}{>{\centering}p{0.25\textwidth}p{0.2\textwidth}p{0.2\textwidth}>{\centering\arraybackslash}p{0.15\textwidth}}
        \toprule
        \multirow{2}{*}{Country} & \multicolumn{2}{c}{GDP} & Change \\
        \cmidrule{2-3} \\
        {} & 2010 & 2015 & {} \\
        \midrule
        United States & 14964.400 & 18036.650 & 20.53\% \\
        China & 5812.464 & 11226.186 & 93.14\% \\
        Japan & 5793.455 & 4382.420 & -24.36\% \\
        Germany & 3309.668 & 3365.293 & 1.68\% \\
        United Kingdom & 2246.079 & 2863.304 & 27.48\% \\
        \bottomrule
    \end{tabular}
\end{table}

\end{document}

For table cells where the horizontal alignment is not explictly defined, the default is left alignment. Note that if you want to change the alignment of last column, the \arraybackslash command must also be supplied, or you will encounter errors when compiling the LaTeX source code:

Extra alignment tab has been changed to \cr.

The reason of this error can be found here if you are interested.

The created table will be like the following:

Defining new column types to simplify things

Writing column width and alignment in the tabular column type option is rather lengthy and error-prone. We can define new column types and use them in the column type option to simplify things.

The \newcolumntype command from array package is used to define new column types, for example:

\newcolumntype{A}{>{\centering}p{0.25\textwidth}}

Using this command, our code now becomes more concise and readable:

Click to show the code.

\documentclass{article}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{array}

\begin{document}

\newcolumntype{A}{>{\centering}p{0.25\textwidth}}
\newcolumntype{B}{p{0.2\textwidth}}
\newcolumntype{C}{>{\centering\arraybackslash}p{0.15\textwidth}}
\begin{table}[t]
    \centering
    \begin{tabular}{ABBC}
        \toprule
        \multirow{2}{*}{Country} & \multicolumn{2}{c}{GDP} & Change \\
        \cmidrule{2-3} \\
        {} & 2010 & 2015 & {} \\
        \midrule
        United States & 14964.400 & 18036.650 & 20.53\% \\
        China & 5812.464 & 11226.186 & 93.14\% \\
        Japan & 5793.455 & 4382.420 & -24.36\% \\
        Germany & 3309.668 & 3365.293 & 1.68\% \\
        United Kingdom & 2246.079 & 2863.304 & 27.48\% \\
        \bottomrule
    \end{tabular}
\end{table}

\end{document}

References