Anyone know what the formula is for rangefinder incline calculation. I don't want to buy the ARC, but would like to compensate for incline angle using my old laser range finder.

The Pythagorean Theorem
Seriously.....just shoot for the horizontal distance. A quick search of the forum will land you PLENTY of threads on this subject.

Good luck.

When I saw Michael Waddell speaking a couple weeks ago, while he was trying to sell everyone his new rangefinder, he told an interesting story. Many years ago he was hunting with an "old pro." When they got to the stand, the man pulled out a rangefinder and a calculator. He would range the ground ahead of him, then start punching in numbers on the calculator.The Pythagorean Theorem is exactly what he was doing.

You can do it that way. Though it's not neccessary.

When you start to realize what we're really dealing with here (in "real-world" bowhunting scenarios)....

An archer 21' in a tree.....shooting at a deer 30yds away............the "compensation" (or....added distance...due to the angle), is a whopping .8yds.

I travel lighter without a calculator, knowing this.

Yeah but if the calculator comes with Scent lok and it's own feeder, THAT might be worth it.

.8 does nothing....leave the calculator at home. Unless your taking 50 yard shots, but thats for another debate

So you're up a tree 30' and the target is 40' from the base of the tree, so the distance from you in the stand to the target is 50'. Would you use/shoot the 40' distance? What's the compensation due to gravity?

GMMAT is right about there being several websites where you can get the formula butyou can figure the horizontal distance by figuring the square root of: The height of your stand squared minus the slant (measured) distance squared.
I, too, was interested in trying to figure it out in my head but after doing some calculations there wasn't that much difference in most cases. I figured that my stand height of 15-20 feet on level ground didn't change the distance very much at all and the longer the shot the less impact the angle had on the distance
It would make a difference if you were shooting down into a deep ravine or steeply uphill.
I have started ranging distances by lazering horizontally across from my tree stand to reference tree trunks at the same height as my stand. If you try this you will see that there really is not much difference if the ground is flat and you are at a reasonable height in your stand.

The distance would be 41.23yds.

You know what the Internet has done???

It's made folks lazy...They think every answer to every problem is at their finger tips, without actually trying things out and forming their own opinion...

IF...You are that concerned about hitting a deer while in your tree stand...
THEN...Get your butt in a tree and practice those shots, then you WILL know...

I've done it, first time was over 30 years ago...

If you still are worried, get a pendulum sight and see how they work...

All of us shoot a little differently, no one has the same form...You need to find out for yourself what happens when you release an arrow from 20 feet up in a tree with all your bowhunting equipment on, including broadheads...

Sorry for the rant...It just seems like there are simple solutions to some silly questions that get asked every week and a half...