I recently received a partial request (first fifty pages) from a legitimate agency, but the submission guidelines and personal request never stated if the partial should be double or single spaced to include the exact fifty pages. I wanted to know if I should double space the pages just in case, since I am sending them off via mail per the agent’s request, or single space to include the actual fifty pages.
Manuscripts, partials, or any submissions to agents and editors should always, always be double-spaced. There is never, ever an exception to this rule unless the agent specifically says she wants it single-spaced.
I’m not sure what you mean by exact fifty pages, but the fifty pages the agent is asking for are double-spaced, so those would be the fifty pages she’s expecting. If you have a chapter break that’s more than fifty pages, then you choose the end of the chapter that’s closest to fifty pages.
Typically this is a question I might answer under my Random Questions posts, except I had a bigger concern when reading this, and that’s a concern about your knowledge of publishing submission guidelines. Before you send anything out to agents I suggest you spend some time on agent blogs, web sites, or, at the very least, reading a book or two on what agents expect from submissions. This is an incredibly basic detail and one I think most of my readers have known or understood for a long time. If you’re asking a question like this my concern is that you are making even bigger mistakes in your submission process and could benefit from a little knowledge before reaching out to agents.
I have a feeling my readers will be able to provide you with a great list of resources and information to help you understand this business better.