Many shoe stores and department stores offer printable shoe sizing charts on their websites. Some stores, such as StrideRite, also offer free apps that can measure shoe sizes. StrideRite's iPad app is available for download from the store's website as of 2015.
Shoe sizing charts are typically available as downloadable PDF files. Select the appropriate size chart for your age and gender, download the chart, and print it. Some stores have additional size charts for specialty footwear such as boots or athletic shoes.
StrideRite offers a printable chart as well, but its RiteFit app for the iPad uses photo recognition technology to analyze images of a child's foot. The app then suggests shoe sizes and tracks growth over time.