# Is there a way to know what is the vertical space that LaTeX is leaving before and after a theorem?

I would like to know if there's some code I can enter in order to find what is the vertical space (in cm or pt) that LaTeX is leaving before and after a theorem.

I'm using

\documentclass[12pt]{article}

and

\usepackage{amsfonts, amsthm, amsmath, amssymb}
• Do you use a theorem package such as amsthm and/or ntheorem? – Mico May 9 '14 at 13:59
• Sorry, I forgot to include that information. I'll edit the question. – User X May 9 '14 at 14:00
• By default, amsthm uses \topsep, that is, the same spacing used around list environments. – egreg May 9 '14 at 14:02
• And how can I use \topsep? Basically, I want to be able to manually add a vertical space that is the same as the vertical space before and after a theorem. – User X May 9 '14 at 14:06
• \vspace{\topsep}? – egreg May 9 '14 at 14:07

## 2 Answers

Preposterous example via repeating materaial from Non italic text in theorems, definitions, examples

\documentclass{article}
\usepackage{mathtools,amsthm,kantlipsum}

\newtheoremstyle{crampedthm}% <name>
{\topsep}% <Space above>
{-3pt}% <Space below>
{\itshape}% <Body font>
{3cm}% <Indent amount>
{\bfseries\itshape}% <Theorem head font>
{:}% <Punctuation after theorem head>
{.5em}% <Space after theorem headi>
{}% <Theorem head spec (can be left empty, meaning `normal')>

\theoremstyle{crampedthm}
\newtheorem{cthm}{Tight Theorem}

\begin{document}
\kant[1]
\begin{cthm}
Roses are red $\iff$ sky is blue such that it is self-evident that this
theorem is true.
\end{cthm}
\kant[1-2]
\end{document}

Here's a list of common length macros from Wikibooks. But as I see from the comments, you already know that \topsep is the length macro you need. If you want to know the length of a length macro, all you have to do is place

\the\textwidth

In your document, which will output the length in pt. Personally, I prefer having metric distances, so I usually just place the pt length into Wolfram-alpha to get an exact conversion.