I am trying to write a unit for decibel (dB) inside a math environment using siunitx package and I cannot figure out how to make it bold.

I understand that instead of using siunitx package and math mode I can just write dB, but I want to figure out how to do it this way.

I have tried \boldmath and \boldsymbol{} but none of them are working.

Here is my code.

    \multicolumn{2}{c}{\textbf{Permissible Noise Exposures}}\\
    \textbf{Duration per Day (in hours)} & \textbf{Sound Level (in \boldmath $\si{dB}$ \footnotemark)} \\
    8 & 90 \\
    6 & 92 \\
    4 & 95 \\
    3 & 97 \\
    2 & 100 \\
    1 & 105 \\
    0.5 & 110 \\
    $\mathtt{\leq}$0.25 & 115 \\
\caption{Permissible Noise Exposures}
\subcaption*{Source: 29 CFR 1910.95, Table G-16}
\footnotetext{When measured on the A scale of a standard sound level meter at slow response.}

And this is the output. Notice that the dB symbol is not bolded. enter image description here


1 Answer 1


I suggest you add the option detect-weight to the \si, \SI, and \num instructions. The option informs siunitx that it should utilize information about the font weight of the surrounding material; if that font weight happens to be bold, it'll be applied to the arguments of \si, \SI, and \num.

For more information about utilizing font-related information from the commands' surrounding material, see section 5.2, "Detecting fonts", of the package's user guide.

enter image description here

\textbf{Sound Level (in \si{dB})}

\textbf{Sound Level (in \si[detect-weight]{dB})}
  • 1
    Thank you so much! This completely answeres my question!
    – Vladimir
    Jun 10, 2020 at 1:11

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