pdfkit generates small scaled pdfs

The problem was about setting the dpi parameter for pdfkit.

So if you encounter the same problem, just set the dpi according to your need. For me, this what I was needed

options = {
            'page-size': 'A4',
            'dpi': 400
        }

I had this same issue. I just changed the default configuration:

PDFKit.configure do |config|
    config.default_options = {
        page_size: 'A4',
        print_media_type: true,
        dpi: 400
    }
end