If there is, I haven't found a way. But this has helped me understand how to do this:
http://www.brewboard.com/index.php?showtopic=31009
There's a formulas in there that should help you - read it sober and well caffeinated
I took what I could and plugged it into a spreadsheet so I can just plug in the numbers and easily see how much DME to add, or how much to cut/lengthen my boil time, etc. I haven't figured out the dilution equation yet - so what I tend to do is add water to the kettle a couple quarts at a time and take readings until I'm close to my pre-boil target. Or I just decide to use the higher gravity and see how the beer turns out. In one case I was under, and instead of adding DME I just rolled with it and made a nice dry IPA that was probably the best beer I'd made to date.
Also, you'll need to know your volumes for accuracy - cheers!