Fruit or Juice in Secondary

I assume that adding fruit or juice during secondary fermentation will increase alcohol percentage. So here's my question. Is there a way to factor that into your abv calculation?
For example, let's say your gravity reads 1.0XX at the beginning of secondary, and then you add fruit, and your reading becomes slightly higher - 1.0XY. How do you adjust your final gravity reading to reflect this change when your batch is done? Any help would be appreciated.

You could try using Hightest's OG formula calculations.

I generally just add the points difference between the two readings to the OG and call it a day...I then compare my "corrected OG" to my actual FG and use the usual methods to estimate ABV.

Still, this is at best an estimation, as you are changing the volume when you make additions:
With with juice you are many times significantly increasing the volume (so you could theoretically actually *decrease* the ABV, as you are adding volume with a minimal increase in fermentable sugar, compared to the the original mead).
If you're using solid fruit, you can probably assume that your volume is changing minimally (you put in fruit, and later on you rack off the solids), although you will usually lose some volume due to racking loss...

The notion that adding fruits or juices will raise the ABV is a common misconception. The volume that gets added when adding fruits and juices means there is significant dilution of the ABV before the fermentation starts again. If you track the volumes carefully you will be able to see this.

Unless you are using ripe grapes, almost any fruit (or juice) you add to a standard strength mead (12-14% ABV) is going to produce a lower level of alcohol. This is easily understood if you look at the potential alcohol of your juice. If the juice has a gravity of 1.090 or below, when fermented it will have less than 12% ABV. Apples/juice usually have gravity around 1.050. The juice from berries usually 1.040 or less. My starfruit comes in at 1.035. If you are adding a fruit, take a sample and juice it and measure the gravity to see for yourself. Unless you are adding juice concentrates, fruit will add a volume of liquid along with their sugar that reduces the over-all ABV.

If you are using Grapes with a BRIX of 25+, or if you have a low ABV mead, then this dilution will not occur. If you added dried fruits, the liquid has all been removed, so you are just adding sugars and that will increase the gravity and the potential alcohol.

Medsen

Thanks for the replies. From what MedsenFey said, it sounds to me that dried fruit might be best for me to use, considering that I had a fairly low OG in the first place (1.085), and I would like to increase my abv if I can, as well as add some flavor. I'm not going to expect to increase it by too much, but maybe a couple of percentage points on the happier side.