What is the difference between a coded and uncoded web design?

The difference between the two is

1. Uncoded is used when the customer only requires the PhotoShop design files (ie. PSD files) from the website design contest. The PSD files can then be taken away and converted into a fully functional website (a number of companies specialize in converting PSD to HTML files). This is recommended if you require a website that contains difficult implementations that a designer would not be suited at doing (such as advanced shopping cart implementation).
   
   Note: Since website/HTML implementation is not the core competency of most designers, we recommend choosing uncoded for best results (not only is it cheaper, but more designers are likely to submit).
   
   
2. Coded requires the designer to produce the design and implement the website. The coded website files need to include HTML implementation, CSS and linking. The customer will often need to provide details on content, number of pages to implement and any coding specific requirements (WC3 standards compatibility etc.). For Coded, we recommend that designers initially provide the design files only during the contest - and only when they get selected they can begin to produce html implementation files for the customer during the Design Handover phase. Please note that in order for designers to provide the coded files, customers will need to purchase the "Coded Website" add-on on Step 3 during the order process.

For more information, we recommend you look at this Help article on running web design contests on DesignCrowd:
http://www.designcrowd.com/help/article/web-design