Tap a row to show it in the summary. Highlighted rows are below your minimum energy or your hit-confidence threshold.
How this calculator works
It is a point-mass trajectory solver: it steps the bullet through the air every 3 feet, applying gravity and drag from the standard G1 or G7 drag table at the bullet's current speed, with air density from your temperature and station pressure. It first finds the barrel angle that hits your zero in zero-day air, then flies the bullet in today's air. Wind drift uses the Didion lag-time rule.
This page runs a direct port of the HoldPoint firmware solver. Automated tests check it against the firmware on every change (within 0.01 in), and the firmware is checked against py-ballisticcalc (level shots within a few hundredths of an inch to 800 yd).
Not modelled: spin drift, Coriolis, aerodynamic jump and humidity, which are a few inches at most inside 500 yd. Your inputs matter far more: measure your muzzle velocity and sight height, and confirm holds on paper before you hunt.
The shot check: how "max ethical range" is worked out
A hold tells you where to aim. It doesn't tell you whether you should take the shot. Three errors stack up every time you do: your own wobble and the rifle's group, how far off your wind call might be, and how far off your range might be. The shot check turns them into one number, the chance that a dead-centre hold lands in the vital zone, at every range on the card.
- You + rifle: your 5-shot group from a field position, spread evenly in all directions (a 5-shot group's extreme spread is about 3 standard deviations).
- Wind call: your typical wind error × this load's drift per mph at that range, left and right.
- Range: your typical ranging error × how fast the bullet is dropping at that range, up and down.
The max ethical range today is the furthest range before the hit chance first falls below your confidence (and, if you set one, before the energy falls below your floor). Change the wind error from 3 to 6 mph and watch it shrink: on a gusty day your honest range is shorter, even with the same rifle.
Long-range software such as Applied Ballistics' WEZ already does this kind of hit-probability analysis for precision shooters. Here it's free, built for hunting, and phrased as the question a hunter actually asks: how far is too far, today? It is a planning aid, not permission. If you're unsure, don't shoot.
Frequently asked questions
What is a realistic group size for the shot check?
Shoot five rounds from the positions you actually hunt from (sitting with sticks, prone off a pack, standing against a tree) at 100 yards and measure the widest spread, centre to centre. Most hunters are surprised: 2 to 4 MOA from field positions is common, versus under 1 MOA off a bench.
Does it work in metric?
Yes. Switch Units to Metric for metres, m/s, grams, centimetres, °C, hPa, km/h and joules. Holds stay in MIL or MOA, which are angles and work in either system.
Should I use G1 or G7?
Use G7 if the bullet maker publishes a G7 BC; it fits long boat-tail bullets better across the whole flight. Otherwise use the G1 number from the box.
What's the difference between MIL and MOA?
Both are angles. 1 MIL is 3.6 inches at 100 yards; 1 MOA is about 1.047 inches at 100 yards. Use whichever your scope's turrets or reticle use.
Why station pressure and not the weather report?
Weather reports adjust pressure to sea level. The bullet only cares about the actual air where you are, which is what an uncorrected barometer (station pressure) shows. At altitude the two can differ by several inHg.
How much energy do I need for deer or elk?
Common rules of thumb are about 1000 ft·lb for deer and 1500 ft·lb for elk. They are guidelines, not law; shot placement and bullet construction matter more.
Can I carry this in the field without a phone?
Yes: print the range card, or use HoldPoint, a pocket version of this calculator on a $2 Arduino Nano clone and a $1.50 OLED screen.