Tree-Stand & Angled Shot Distance Compensator

Gravity pulls straight down and nothing else. It doesn't care which way your bow is pointed. So on a tilted shot it only gets to work across the flat leg of the triangle — the horizontal distance sitting underneath your line of sight.

Your rangefinder measures the long side. Aim for the long side and you've compensated for drop the arrow was never going to have, so it lands high. Up and down do the same thing, which catches people out the first time they shoot uphill at an elk and watch it sail.

Check it: the forest-green line in the drawing is the leg gravity works on. Drag the angle to zero and the two lines lie on top of each other — which is why nobody thinks about any of this on flat ground.

Multiply the line-of-sight range by the cosine of the angle and you have the rifleman's rule. In a vacuum it isn't even an approximation — it's exact. That's why angle-compensating rangefinders use it and why it has served shooters well for a century.

An arrow bends it slightly. It leaves the string at roughly a tenth of a bullet's speed, so it climbs a much steeper arc and hangs in the air far longer. Two things follow. Gravity picks up a component along the flight path itself, which quietly adds distance uphill and takes it away downhill. And because the arrow keeps slowing down, flight time grows faster than distance does, which pushes the answer the other way. The tool solves the whole thing numerically rather than reaching for the shortcut, and prints the plain cosine figure beside it so you can see the gap.

Check it: at 40 yd and 25 degrees down, cosine and the honest answer agree to about a tenth of a yard — nothing at all. Point that same shot uphill and cosine reads roughly nine tenths of a yard short. So cosine isn't wrong. It just isn't the last word, and what's left of the difference grows as the arrow gets slower and the angle gets steeper.

Shooting uphill, gravity works against the arrow along its path as well as across it, so the arrow takes a fraction longer to cover the ground and falls a fraction further. Downhill, gravity helps it along and the reverse happens. Drag pulls the other way, and it pulls on both. Uphill the two effects stack. Downhill they fight, and which one wins depends on how steep you are.

Check it: at 40 yd on a 285 fps hunting setup, uphill runs about half a yard longer than cosine at 15 degrees and about one and three quarter yards longer at 45. Downhill sits a tenth of a yard under cosine at 15 degrees, lands right on it around 25, and creeps half a yard above by 45. Honest summary: cosine is good to about a yard either way, and it errs short going uphill. If you've read that uphill shots hit higher than downhill ones at the same angle — that's this, and it's worth about a yard, not the five it sometimes gets credited with.

Most calculators take your stand height and the distance and hand you an angle. That quietly assumes you shoot from your ankles at something with no body.

Standing and at full draw, your arrow rest sits roughly four and a half feet above the platform. A whitetail carries its vitals roughly two and a half to three feet off the ground. So a 20 ft stand gives about 22 ft of real vertical difference, not 20. The tool works rest-to-vitals and lets you set both ends — sitting drops the rest by more than a foot, and an elk carries its vitals well over a foot higher than a whitetail does.

Check it: at 12 yd from a 20 ft stand, counting the rest and the vitals moves the angle by about two degrees. At 40 yd it's under one. Steep and close is where the small print earns its keep, which turns out to be the pattern for everything on this page.

Speed off the string is the biggest lever here. A slower arrow spends longer in the air, falls further, and needs a bigger correction for the same angle. That's why a trad shooter at 20 yards is dealing with numbers a compound shooter doesn't meet until 40.

Drag is a steady bleed of speed per unit of distance, set by what's hanging in the air: low-profile target vanes at the bottom, hunting vanes in the middle, four vanes or a full helical higher, long feathers highest, with a fixed head costing more than a mechanical one. These are the same constants the Trajectory Visualizer and the Broadhead Flight & Tuning Stability Checker use, deliberately — two Lab tools disagreeing about the same arrow would be worse than either of them being slightly off.

Arrow weight sits out of the drag calculation. In reality a heavier shaft carries the same drag on more mass and bleeds speed a little more slowly; across a bowhunting distance that's a couple of fps, so the Lab treats it as second-order and uses weight for the punch figures instead.

Check it: chronograph three arrows, average them, and put that number in. A 285 fps setup with hunting vanes and a fixed head arrives at 40 yd doing about 247 fps here. If your bow reads 270 off the string rather than 285, everything downstream corrects with it — and the speed slider is the one worth getting right before you trust anything else on the page.

This takes the pin setting you'd use for the raw rangefinder number, puts it on the angled target, and works out where the arrow crosses the line of sight. It's measured square to that line, because that's the direction the miss appears in when you're looking down the shaft — the gap between where you aimed and where the hole is.

Here's where the tool disagrees with a lot of what gets written about tree stands. The yardage correction from a stand is real, but the miss is small: 20 ft up with a deer at 15 yards comes out under an inch high on a 285 fps setup, and 25 ft up at 12 yards is about an inch. Not because the angle is gentle — that one is over 35 degrees — but because an arrow barely drops at all inside 15 yards, so there's almost no drop for you to over-correct.

The big misses live out west. 55 yards at 28 degrees down a canyon works out around 9 inches high, and an uphill elk at 45 yards and 32 degrees is close to 7. Long plus steep is what hurts, and that's the situation where a rangefinder doing the arithmetic for you pays for itself.

Check it: none of which lets stand hunters off. What the angle does from 20 ft up shows up in the cross-section panel rather than in the yardage — the arrow arrives on a slant and leaves somewhere you didn't plan. Read that one before this one.

A true aim distance of 34.2 yards is useless if your sight goes 30, 40, 50. So the tool finds the pin whose sight line crosses closest to where the arrow needs to be, then works out how far high or low that pin sits on this particular shot — in inches, on the animal, not in yards.

That's the number worth committing to memory, because gap shooting between pins is guesswork otherwise. If you run a single adjustable pin it simply tells you what to dial. If you shoot without a sight it gives you the equivalent level distance and leaves the gap to you, because your anchor and your arrow length set that, not the bow — the Trajectory Visualizer works the inches out if you want them.

Check it: pick a pin, shoot a level target a few yards past what it's sighted for, and measure how low the group sits. Set the tool to the same numbers with the angle at zero and compare. If your group is lower than the tool says, your arrow is slower than the slider thinks.

The third axis is what keeps your sight bubble telling the truth once the bow is tilted up or down. If it's out, the bubble reads level when the bow isn't, you cant the bow to centre it, and the arrow goes sideways. The steeper the shot, the more cant the error induces.

How far off you end up depends on three things: how far the sight is out, how steep the shot is, and how much elevation the pin is holding at that range. The tool multiplies all three. What comes out is smaller than the figure that gets repeated in threads — a 2 degree error at 25 degrees and 40 yards lands at about six tenths of an inch, not the three to five inches often quoted. Push it to 3 degrees at 45 degrees and 60 yards and you're at roughly two and a half inches.

None of which means skip it. It's free accuracy, it stacks with every other error on a steep shot, and it costs you twenty minutes with a plumb line. It just isn't the thing making you miss from 18 feet up at 15 yards. The angle is.

Check it: hang a weighted string, level your first axis on it, then tilt the bow through a steep angle and watch whether the bubble drifts. If it does, that drift is your error — and most sights will let you take it out.

An arrow coming in on a downward angle keeps going down once it's inside. Across the width of the chest it loses the chest width multiplied by the tangent of the angle. So it exits lower than it entered — sometimes much lower.

On a broadside whitetail that's around 16 inches of chest against about 10 inches of usable vitals. At 20 degrees the arrow moves nearly 6 inches on the way through, which still fits if the entry sits in the top half — and that's what the tool's aim-point figure is telling you to do. Somewhere in the high twenties the traverse eats the whole vital area, and one lung is the best the geometry will give you no matter how well you shoot it. A 25 ft stand with a deer 12 yards out is already past that line.

That's the arithmetic underneath a piece of advice on every stand-hunting thread: let the deer walk out from under you. Ten more yards flattens the angle far more than ten fewer feet of stand height would. And unlike the yardage problem, this one gets worse as the shot gets closer.

Check it: the cross-section puts the entry where it needs to be for the exit to stay inside the box. When the exit dot leaves the box, the tool says so plainly rather than offering you an aim point that can't work.

• String jump. A deer can drop several inches before the arrow arrives. It's a reaction to sound, it varies with the animal and how alert it is, and no calculator can put a number on it. It argues for aiming low; the angle argues for aiming high. They aren't the same size and they don't cancel.
• Bow torque and form. Shooting steeply downhill bends you at the waist and changes how the bow sits in your hand. That's a bigger source of misses than anything on this page, and it's fixed by practising from the stand rather than by arithmetic.
• Wind. Handled in the Trajectory Visualizer instead, because it needs direction as well as speed.
• Broadhead planing. A fixed head that isn't tuned steers on its own. The Broadhead Flight Checker is the place for that.
• Animals standing on a slope. The cross-section assumes the body is upright. An elk quartering across a steep sidehill has its own tilt, which adds to or cancels yours.
• Sight-height geometry. Treated as a small constant. On a very steep shot at very close range it does a little more than that, and the tool will read slightly optimistic.

• Speed first. Chronograph three arrows, average them, put that in. Nothing else here is worth much until this is right.
• Angle test. Find a bank or a stand, range a target at a real angle, and shoot it twice — once holding the raw reading, once holding the number here. Measure the gap between the two groups and compare it to the miss figure.
• From the stand. Hang a target at ground level and shoot it from your actual stand at 10, 15 and 25 yards. That's the band where the angle bites hardest and where you'll learn the most.
• Third axis. Plumb line, then a steep shot at 40 yards. Any consistent left or right bias is your answer.

If your results sit outside what's here, your setup is telling you something the arithmetic can't — and that's worth more than any estimate. Share your link in the comments below and say what your bow actually did.