A vertical line in a table is elongated when using multirow

Question

I have a table where the first vertical line is longer than the rest. This whole table was a rushjob so I might have missed something obvious.

I suspect this has something to do with my use of multirow but I haven't been able to resolve the issue. I have tried using the solutions from Too long vertical lines in table but nothing seems to work. Does anyone have a good clue about what might be causing this and what I can do to fix it?

Code:

\begin{table}[th]
\centering
    \captionsetup{justification=centering}
    \caption{Table showing the Bp length of primer set 1, 2 and 3 after restriction cutting with HindIII.}
    \begin{tabular}{c|c|c}
    Set \textnumero & Calculations & \textbf{Bp} \\
    \hline
    \multirow{4}{*}{Set 1} & \footnotesize{$R-\text{Res}+1$} & \multirow{2}{*}{$512$}\\
     & $23642-23131+1$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{*}{$4049$}\\
     & $23131-19082$ & \\
    \hline
    \multirow{6}{*}{Set 2}& \footnotesize{$R-\text{Res}_2+1$} & \multirow{2}{*}{$2185$} \\
     & $27342-25158+1$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}_2-\text{Res}_1$} & \multirow{2}{*}{$2027$} \\
     & $25158-23131$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{*}{$146$}\\
     & $23131-22985$ & \\
    \hline
    \multirow{8}{*}{Set 3} & \footnotesize{$R-\text{Res}_3+1$} & \multirow{2}{*}{$2465$} \\
     & $40049-37585+1$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}_3-\text{Res}_2$} & \multirow{2}{*}{$125$} \\
     & $37585-37460$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}_2-\text{Res}_1$} & \multirow{2}{*}{$564$} \\
     & $37460-36896$ & \\
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{*}{$1442$}\\
     & $36896-35454$ & \\
    \label{bp:HindIII}
    \end{tabular}
\end{table}

When compiled:

The left vertical line stretches a bit further than the right.

Answer 1

Let me convert my comment to an answer:

• In last row of table you have \label{bp:HindIII} which should not be inside tabular. Move it immediately after \caption{...}
• Code for your table can be shorter with use tabularray package:

\documentclass{article}
\usepackage{tabularray}
\UseTblrLibrary{amsmath, booktabs}
\DeclareMathOperator{\Res}{Res}
\usepackage{caption}
    \captionsetup{justification=centerlast}
\begin{document}
    \begin{table}[ht]
    \centering
\caption{Table showing the Bp length of primer set 1, 2 and 3 after restriction cutting with HindIII.}
\label{bp:HindIII}
    \begin{tblr}{colspec={c|Q[c,mode=math]|Q[c,mode=math]},
                 row{1} = {mode=text, c},
                 cell{even}{2} = {font=\footnotesize, c},
                 }
Set \textnumero 
    & Calculations  & \textbf{Bp} \
    \midrule
\SetCell[r=4]{c}    Set 1
    & R-\Res+1      & \SetCell[r=2]{c}     512  \
    & 23642-23131+1 & \
    \midrule
    & \Res-F        & \SetCell[r=2]{c}    4049  \
    & 23131-19082   & \
    \midrule
\SetCell[r=6]{c}    Set 2
    & R-\Res_2+1    & \SetCell[r=2]{c}    2185  \
    & 27342-25158+1 & \
    \midrule
    & \Res_2-\Res_1 & \SetCell[r=2]{c}    2027  \
    & 25158-23131   & \
    \midrule
    & \Res-F        & \SetCell[r=2]{c}     146  \
    & 23131-22985   & \
    \midrule
\SetCell[r=8]{c}    Set 3
    &  R-\Res_3+1   & \SetCell[r=2]{c}    2465  \
    & 40049-37585+1 & \
    \midrule
    & \Res_3-\Res_2 & \SetCell[r=2]{c}     125 \
    & 37585-37460   & \
    \midrule
    & \Res_2-\Res_1 & \SetCell[r=2]{c}     564 \
    & 37460-36896   & \
    \midrule
    & \Res-F        & \SetCell[r=2]{c}    1442 \
    & 36896-35454   & \
    \end{tblr}
\end{table}
\end{document}

Edit: A bit more sophisticated version of the above MWE with even shorter table code producing nicer (to my opinion) table form (as exercise for use of the tabularray package):

• reduced vertical space after even rows
• drawing of the horizontal lines are defined in document and table preamble
• considered is two column document

\documentclass[twocolumn]{article}
\usepackage{tabularray}
\usepackage{amsmath}
    \DeclareMathOperator{\Res}{Res}
\usepackage[font=small, labelfont=bf,
            justification=centerlast
            ]{caption}
\begin{document}
    \begin{table}[ht]
    \centering
\caption{Table showing the Bp length of primer set 1, 2 and 3 after restriction cutting with HindIII.}
\label{bp:HindIII}
\begin{tblr}{colspec= {c | Q[c,mode=math] | r},
             row{1} = {mode=text, c},
             cell{even}{2} = {font=\footnotesize, c},
             cell{even}{3} = {r=2}{ },
             row{even} = {belowsep=-2pt},
             hline{even[1-X]} = {0.25pt},
              }
Set \textnumero

    & Calculations      & \textbf{Bp} \
\SetCell[r=4]{c}    Set 1
    & R - \Res + 1      &   512    \
    & 23642 - 23131 + 1 &   \
    & \Res-F            &   4049   \
    & 23131-19082       &   \
\SetCell[r=6]{c}    Set 2
    & R-\Res_2+1        &   2185   \
    & 27342-25158+1     &   \
    & \Res_2-\Res_1     &   2027   \
    & 25158-23131       &   \
    & \Res-F            &   146    \
    & 23131-22985       &   \
\SetCell[r=8]{c}    Set 3
    &  R-\Res_3+1       &   2465   \
    & 40049-37585+1     &   \
    & \Res_3-\Res_2     &   125    \
    & 37585-37460       &   \
    & \Res_2-\Res_1     &   564    \
    & 37460-36896       &   \

    & \Res-F            &   1442   \
    & 36896-35454       &   \
\end{tblr}
    \end{table}
\end{document}

Answer 2

You can avoid the problem if you don't use \\ to start a new (empty) row at the end:

\documentclass{article}
\usepackage{multirow}
\usepackage{caption}
\usepackage{amsmath}
\begin{document}
\begin{table}[th]
\centering
    \captionsetup{justification=centering}
    \caption{Table showing the Bp length of primer set 1, 2 and 3 after restriction cutting with HindIII.}
    \begin{tabular}{c|c|c}
    Set \textnumero & Calculations & \textbf{Bp} \
    \hline
    \multirow{4}{}{Set 1} & \footnotesize{$R-\text{Res}+1$} & \multirow{2}{}{$512$}\
     & $23642-23131+1$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{}{$4049$}\
     & $23131-19082$ & \
    \hline
    \multirow{6}{}{Set 2}& \footnotesize{$R-\text{Res}_2+1$} & \multirow{2}{}{$2185$} \
     & $27342-25158+1$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}_2-\text{Res}_1$} & \multirow{2}{}{$2027$} \
     & $25158-23131$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{}{$146$}\
     & $23131-22985$ & \
    \hline
    \multirow{8}{}{Set 3} & \footnotesize{$R-\text{Res}_3+1$} & \multirow{2}{}{$2465$} \
     & $40049-37585+1$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}_3-\text{Res}_2$} & \multirow{2}{}{$125$} \
     & $37585-37460$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}_2-\text{Res}_1$} & \multirow{2}{}{$564$} \
     & $37460-36896$ & \
    \cline{2-3}
     & \footnotesize{$\text{Res}-F$} & \multirow{2}{}{$1442$}\
     & $36896-35454$ & 
    \label{bp:HindIII}
    \end{tabular}
\end{table}
\end{document}