Draw a rounded corner rectangle in LaTeX using Tikz

Let’s learn how to draw a rounded corner rectangle with Tikz in LaTeX.

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \draw[rounded corners=20pt, thick] (0,0) rectangle (4,2);
\end{tikzpicture}
\end{document}

Output:

Here, I am using  rounded corners=20pt so the radius of the rectangle corners becomes 20pt. You can change this value according to your needs.

Then in the second parameter, I am using thick. This is the border thickness. You can make it thin or ultra thick. These are pre-defined thicknesses. If you want to customize the thickness you can use:

line width=1.5pt. It does not matter if you are using this parameter in the first place or second. You can do it like this:

\draw[rounded corners=20pt, line width=1.5pt]

A specific corner rounded in Tikz (Top Right corner only)

If you want to make a specific corner rounded using Tikz, you can draw a straight line and only make angular corners for your rectangle where it needs to be.

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \draw[line width=1.5pt] 
        (0,0) -- (4,0)                     % Bottom edge
        -- (4,1.5)                         % Right edge up to where the rounding starts
        arc[start angle=0, end angle=90, radius=0.5cm]  % Round the top-right corner
        -- (0.5,2)                         % Top edge (shortened by the rounding radius)
        -- (0,2)                           % Continue to the top-left corner
        -- cycle;                          % Left edge and close
\end{tikzpicture}
\end{document}

Output:

You can use the same logic for other corners as well.

I know this might be tough but you can do it. Let me know if you face any issues in the comment section below.