Sorry - that sounds like a really stupid question, but is an A4 sheet, single spaced (660 words) okay, or should I be aiming to further cut the word count.
I can clearly see the appeal of it all being contained in a single page.

Yes, one page, single spaced, sensible margins, 12pt Times New Roman.

If you indent the first line of the paragraphs, you don't need a double-line space between them and gain a few extra lines that way.

Thanks Emma - I'd not thought about font ...

My final version came in at 638, and I managed to fit it all on one page.

Synopses are truly the devil's work, aren't they? An absolute pig to write, and always less good than we could wish. Best of luck with yours

You're welcome, Sandra. TNR is industry standard, but it also has the merit of taking up the least space for that point-size.

Best of luck with it!

What I would love is to get someone else to write my synopsis. They are so hard to write. Would anyone be up for that, once I've put all the details down. I'd be happy to return the favour.

What I would love is to get someone else to write my synopsis.

Oh, wouldn't that be a wonderful service? I think some places do actually offer this. Trouble is, I've heard that agents can tell immediately that it's been done by someone else (not sure how, but there's probably something in the style/wording that gives it away).

Alos, unless the synopsis writer has read the whole of your novel, how would they possibly manage to compress it into 500-600 words and still highlight the points that you most want to emphasise?

LoL Jaytee!

I think it can be very useful to get someone else who's read the novel help you with the synopsis, because sometimes it's easier for them to see the big bones and ignore the subplots, side-issues etc. etc. that you've spent so many months lovingly creating and now can't see past.

once I've put all the details down.

But that is the synopsis! If you've done that, what still needs evoking is the atmosphere etc, and I'm not sure someone who hasn't read the novel can really do that.

A conversation, though, could be very useful. Maybe one way to start a synopsis is to buy someone a drink and get them to question you: "What's it about?"

Nicola Morgan's little e-book Write A Great Synopsis is very good, I think - her top tip (among many others) is to start with a single sentence describing the book, and then a paragraph, after which a whole page will feel like luxury.

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FWIW, this is my take on the whole not-so-horrible-really business of writing synopses:

http://emmadarwin.typepad.com/thisitchofwriting/2011/06/relax-its-only-a-synopsis.html

I say not-so-horrible-really because I've come to find them an incredibly useful tool at various stages of developing the novel.

<Added>

I'm sure agents and editors can tell when someone else has written it, just as any of us can tell those first-person "I thought my life had ended" pieces in the glossies were written by a journo, long before you've got out the magnifying glass and read "as told to Jane Bloggs"

Yes interesting. of course you would be able to detect someone else's writing style.
Rats.
Writing the synopsis on last book did help me develop plot.

I'll take a look at the page on your website Emma!

Either it's an "everything is dreadful" day or The Truth Will Out, but my synopsis has thrown up what look like inescapable plot holes, and third draft chapter 1 suddenly looks denuded ...

First I'll go and do some printmaking and then I'll read your 'Relax' post.

I may be some time.

my synopsis has thrown up what look like inescapable plot holes,

That's one of the reasons it's such a valuable exercise, long before you're having to do it in order to submit the book anywhere. It happened to me, about a third of the way through a novel: I had to write a longish synopsis for the whole thing, and it was only then that I realised I just didn't have a plot in the second half. The bits didn't connect up and the engine was never going to be able to turn. Thank goodness I did - it was a pain, but much better than hitting that wall and fumbling around for weeks trying to make it work (Which apart from anything else tends to throw my other writerly horse-sense of character, prose etc.)

There's something about having to express something in continuous prose which means you notice when things don't join up, as no amount of planning by other means seems to.

Good luck!

such a valuable exercise, long before you're having to do it

Yes, and I started writing it long ago, which is why it's so demoralising at this stage (though it could just be that I'm having a Bad Day)
I have, at least, done a one sentence synopsis:
Rose Madigan, as successful a journalist as she is at deceiving herself about her interest in Baz Rose, persuades him to masquerade as her husband in order to investigate the higher-than-reasonable number of grooms who return from a honeymoon cruise as widowers.