Resolve Overfull \hbox warning in tabular

Question

I have made this table but I have a warning:

"Overfull \hbox (5.0pt too wide) detected at line 336".

Can someone help me, please?

        \documentclass[final,3p,times]{elsarticle}
        \usepackage{amssymb} 
        \usepackage{amsmath}
        \usepackage{graphicx}
        \usepackage[export]{adjustbox}
        \usepackage{tabularx}
        \usepackage{multirow}
        \usepackage{booktabs}
        \usepackage{siunitx}
        \usepackage{natbib}


        \begin{document}
        \begin{table}[!ht]
                  \caption{Numerical Analysis of the decrypted images}
           \label{Metric}
           \centering
             \begin{tabular}{ll
                S[table-format=1.4]
           *{5}{S[table-format=-1.4]}
                            }
         \toprule
          \multirow{2}{*}[-1ex]{Images}
          & \multirow{2}{*}[-1ex]{Metric}
                         & \multicolumn{4}{c}{Proposed Results}     &{References}           \\
            \cmidrule{3-6}
     &            & {200}    & {400}     &  {600}     & {800}     &       \\
           \midrule 
         \multirow{3}{*}{Goldhill}
            & PSNR & 57.0074  & 59.2239 & 61.0477 & 63.3011  &    \\
            &SSIM & 0.9943  &  0.9976 & 0.9987  & 0.9993&  \\
            & ESR &  0.7470   & 0.5461&  0.3487 &  0.3487 &  \\     
      \bottomrule
        \end{tabular}
    \end{table}
   \end{document}

Answer 1

Two problems and one suggestion:

• You specify more columns (8) than your table has (7)

• Also your numbers are longer than what you tell siunitx, this causes the overfull box warning. If your numbers have 2 digits before the decimal separator and 4 digits afterwards, you need to specify a format of 2.4 and not 1.4

• And just my personal opinion: Your table looks even better if the rules are trimmed a little bit

---

\documentclass[final,3p,times]{elsarticle}
\usepackage{amssymb} 
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage[export]{adjustbox}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{booktabs}
\usepackage{siunitx}
\usepackage{natbib}
\usepackage{caption}

\begin{document}

\begin{table}[!ht]
    \caption{Numerical Analysis of the decrypted images}
    \label{Metric}
    \centering
    \begin{tabular}{@{}ll *{4}{S[table-format=2.4]} l@{}}
        \toprule
        \multirow{2}{*}[-0.5ex]{Images} 
            & \multirow{2}{*}[-0.5ex]{Metric}
            & \multicolumn{4}{c}{Proposed Results}
            &\multirow{2}{*}[-0.5ex]{References}  \\
        \cmidrule(rl){3-6}
        & & {200} & {400} & {600} & {800} & \\
        \midrule 
        \multirow{3}{*}{Goldhill}
        & PSNR & 57.0074  & 59.2239 & 61.0477 & 63.3011 &  \\
        & SSIM & 0.9943   & 0.9976  & 0.9987  & 0.9993  &  \\
        & ESR  & 0.7470   & 0.5461  & 0.3487  & 0.3487  &  \\     
        \bottomrule
    \end{tabular}
\end{table}

\end{document}