Getting Started
Text Formatting
Mathematical Expressions
Document Structure
Page Layout
Errors & Troubleshooting
Merging Table Cells in LaTeX: \multicolumn and \multirow
Horizontal merges are \multicolumn, built into LaTeX. Vertical merges are \multirow, from the package of the same name. They combine, with one non-obvious rule about empty placeholder cells that this page spells out. (New to tables entirely? Start with the tables guide.)
\multicolumn: spanning columns
Three arguments: how many columns to swallow, the alignment spec for the merged cell, the content. The second argument replaces the column spec for that stretch — including the vertical bars. That is why the example writes {|c|}: forget the bars and the table's border develops a gap exactly one header wide, which is the most common \multicolumn bug report.
A useful degenerate case: \multicolumn{1}{c}{...} overrides the alignment of a single cell — the standard way to center one header over a column of right-aligned numbers.
\multirow: spanning rows
The * in the width slot means "natural width" — right for short labels. Give a real width like {3cm} only when you want the cell's text to wrap.
The rule that trips people: the rows being spanned still need their cell in that column — an empty one, hence the bare & opening the second row above. \multirow only draws text across rows; the table grid underneath is unchanged, and every row must still account for every column.
Spanning rows AND columns
Wrap the \multirow inside the \multicolumn — that nesting order, not the other way around. The second row then needs an empty \multicolumn of the same width as a placeholder:
Miss the empty \multicolumn{2}{|c|}{} on the second row and the column count no longer adds up — you get Extra alignment tab has been changed to \cr, an error message with no obvious connection to its cause.
With booktabs: \cmidrule under spanning headers
In a booktabs table you do not run a full rule under a spanning header — you underline just its columns with \cmidrule(lr){2-3}. The (lr) trims the rule at both ends so adjacent rules do not fuse into one line:
This header pattern — grouped columns, trimmed partial rules, no vertical bars anywhere — is the standard for results tables in papers, and referees recognize it on sight.
When multirow's centering drifts
\multirow positions its content by assuming the spanned rows have normal height. A tall neighbor — a stacked fraction, an \includegraphics, a wrapped paragraph — stretches the rows and the label ends up visibly high or low. Escalate through these fixes:
- Span more "virtual" rows or use the optional fixup argument:
\multirow{2}[2]{*}{...}shifts the anchor by half-line steps (its exact meaning depends on bigstruts, but in practice you tune the integer until it sits right) - Brute-force the position:
\multirow{2}{*}{\raisebox{-4pt}{Label}} - Rethink: move the tall content out of the spanned rows, or transpose the table so the merge becomes a \multicolumn
These offsets are font- and size-dependent. Re-check every \raisebox nudge after switching document class or font size — they do not travel.
Full worked example
A grouped header spanning two columns plus a row label spanning two rows, in booktabs style — the shape most results tables reduce to:
Every merged-cell technique on this page appears here once: \multicolumn for the group header, \cmidrule trimmed under it, \multirow for the model names, and empty cells holding the grid together.
Frequently asked questions
How do I merge cells horizontally in a LaTeX table?
\multicolumn{2}{c}{Header} merges 2 cells with centered content. It is built into LaTeX — no package. The three arguments are: number of columns to span, the alignment spec for the merged cell (including any vertical bars, which you must restate), and the content.
How do I merge cells vertically in LaTeX?
\multirow{2}{*}{Label} from the multirow package spans 2 rows; the * lets the content set its own width. On the rows below, leave that column's cell empty — the text was already placed by \multirow, the empty cell just reserves the space.
Can a cell span both rows and columns?
Yes: wrap a \multirow inside a \multicolumn, e.g. \multicolumn{2}{c}{\multirow{2}{*}{Big cell}}. On the following row, put an empty \multicolumn{2}{c}{} in the same position so the column count still adds up.
Why is my multirow text not vertically centered?
\multirow centers based on its row-count argument assuming normal-height rows. Tall content in neighboring cells stretches the rows and the estimate drifts. Nudge it with the optional vpos/fixup arguments or wrap the content in \raisebox — or better, restructure so the tall content is not fighting the span.
Merging Table Cells in LaTeX: \multicolumn and \multirow
Horizontal merges are \multicolumn, built into LaTeX. Vertical merges are \multirow, from the package of the same name. They combine, with one non-obvious rule about empty placeholder cells that this page spells out. (New to tables entirely? Start with the tables guide.)
\multicolumn: spanning columns
Three arguments: how many columns to swallow, the alignment spec for the merged cell, the content. The second argument replaces the column spec for that stretch — including the vertical bars. That is why the example writes {|c|}: forget the bars and the table's border develops a gap exactly one header wide, which is the most common \multicolumn bug report.
A useful degenerate case: \multicolumn{1}{c}{...} overrides the alignment of a single cell — the standard way to center one header over a column of right-aligned numbers.
\multirow: spanning rows
The * in the width slot means "natural width" — right for short labels. Give a real width like {3cm} only when you want the cell's text to wrap.
The rule that trips people: the rows being spanned still need their cell in that column — an empty one, hence the bare & opening the second row above. \multirow only draws text across rows; the table grid underneath is unchanged, and every row must still account for every column.
Spanning rows AND columns
Wrap the \multirow inside the \multicolumn — that nesting order, not the other way around. The second row then needs an empty \multicolumn of the same width as a placeholder:
Miss the empty \multicolumn{2}{|c|}{} on the second row and the column count no longer adds up — you get Extra alignment tab has been changed to \cr, an error message with no obvious connection to its cause.
With booktabs: \cmidrule under spanning headers
In a booktabs table you do not run a full rule under a spanning header — you underline just its columns with \cmidrule(lr){2-3}. The (lr) trims the rule at both ends so adjacent rules do not fuse into one line:
This header pattern — grouped columns, trimmed partial rules, no vertical bars anywhere — is the standard for results tables in papers, and referees recognize it on sight.
When multirow's centering drifts
\multirow positions its content by assuming the spanned rows have normal height. A tall neighbor — a stacked fraction, an \includegraphics, a wrapped paragraph — stretches the rows and the label ends up visibly high or low. Escalate through these fixes:
- Span more "virtual" rows or use the optional fixup argument:
\multirow{2}[2]{*}{...}shifts the anchor by half-line steps (its exact meaning depends on bigstruts, but in practice you tune the integer until it sits right) - Brute-force the position:
\multirow{2}{*}{\raisebox{-4pt}{Label}} - Rethink: move the tall content out of the spanned rows, or transpose the table so the merge becomes a \multicolumn
These offsets are font- and size-dependent. Re-check every \raisebox nudge after switching document class or font size — they do not travel.
Full worked example
A grouped header spanning two columns plus a row label spanning two rows, in booktabs style — the shape most results tables reduce to:
Every merged-cell technique on this page appears here once: \multicolumn for the group header, \cmidrule trimmed under it, \multirow for the model names, and empty cells holding the grid together.
Frequently asked questions
How do I merge cells horizontally in a LaTeX table?
\multicolumn{2}{c}{Header} merges 2 cells with centered content. It is built into LaTeX — no package. The three arguments are: number of columns to span, the alignment spec for the merged cell (including any vertical bars, which you must restate), and the content.
How do I merge cells vertically in LaTeX?
\multirow{2}{*}{Label} from the multirow package spans 2 rows; the * lets the content set its own width. On the rows below, leave that column's cell empty — the text was already placed by \multirow, the empty cell just reserves the space.
Can a cell span both rows and columns?
Yes: wrap a \multirow inside a \multicolumn, e.g. \multicolumn{2}{c}{\multirow{2}{*}{Big cell}}. On the following row, put an empty \multicolumn{2}{c}{} in the same position so the column count still adds up.
Why is my multirow text not vertically centered?
\multirow centers based on its row-count argument assuming normal-height rows. Tall content in neighboring cells stretches the rows and the estimate drifts. Nudge it with the optional vpos/fixup arguments or wrap the content in \raisebox — or better, restructure so the tall content is not fighting the span.
Getting Started
Text Formatting
Mathematical Expressions
Document Structure
Page Layout
Errors & Troubleshooting