Zeroing

How Many Clicks to Zero a Scope? From Millimetres to the Turret

Published 6 September 2026

You can see the group is high and a touch left. What you can't see is how many clicks to zero the scope — that takes the offset in millimetres, the distance, and your turret's click value, and a conversion most of us do wrong at the bench. This guide gives you the arithmetic, a calculator that does it for you, and shows how Pellet App reads the whole thing straight off a photo of the target.

The problem is the conversion, not the shooting

Zeroing is simple in outline: shoot a group, measure how far its centre sits from the aim point, dial that out, confirm. Every step is easy except the third. A turret doesn't move the point of impact in millimetres — it moves it by an angle, and how many millimetres that angle is worth depends entirely on how far away the target is. So the question "how many clicks?" always has three inputs, and if you skip one you dial the wrong amount.

Here is the whole calculation in one line, and the rest of the page unpacks it:

Step 1: measure the offset from the group centre

Two things matter here. First, measure to the centre of the group, not to the best shot or the worst one — the centre is the rifle's actual point of impact, and one or two outliers shouldn't drag your zero around. Second, keep elevation and windage separate. They live on different turrets, and they are almost never the same number.

Measure in millimetres. Imperial is fine if that is how your ruler is marked, but the arithmetic below is far cleaner in metric — which is one reason the MRAD system is easier to live with than MOA.

Step 2: convert millimetres to an angle

The conversion the whole thing hinges on is this: 1 MRAD (one milliradian, or "mil") subtends 1 millimetre at 1 metre. Which means it subtends 10 mm at 10 m, 30 mm at 30 m, and 43 mm at 43 m. So the angular offset of your group is simply:

MRAD = offset_mm ÷ distance_m

A group 2.7 mm high at 43 m is 2.7 ÷ 43 = 0.063 MRAD high. That's it — no trigonometry, no unit juggling. This is exactly why the MRAD system exists, and why Pellet App reports group size and corrections in it.

If your turret is marked in MOA (minutes of angle), the shape of the calculation is the same but the constant is uglier: 1 MOA is 29.1 mm at 100 m, or 0.291 mm per metre of range. So:

MOA = offset_mm ÷ (distance_m × 0.291)

The same 2.7 mm at 43 m is 2.7 ÷ (43 × 0.291) = 0.22 MOA. (Or convert once: MOA = MRAD × 3.44.)

Working in yards? Multiply by 0.914 to get metres first, then carry on. 30 yards is 27.4 m.

Step 3: divide by your click value

Every turret moves the reticle a fixed angle per click, and that value is printed on the turret cap or in the manual. Most air-rifle scopes are one of the following:

• 0.1 MRAD per click — the metric standard, increasingly common on scopes sold in the UK and Europe
• ¼ MOA per click — the traditional standard, still very common
• ⅛ MOA per click — fine-adjust target scopes
• ½ MOA per click — some budget and compact scopes

Divide the angle by the click value, round to the nearest whole click, and that is what you dial. The 0.063 MRAD example on a 0.1 MRAD turret is 0.63 clicks → 1 click. On a ¼ MOA turret, 0.22 MOA ÷ 0.25 = 0.88 → also 1 click.

What one click is worth at typical air rifle distances

Distance	0.1 MRAD click	¼ MOA click	⅛ MOA click
10 m	1.0 mm	0.7 mm	0.4 mm
20 m	2.0 mm	1.5 mm	0.7 mm
25 m	2.5 mm	1.8 mm	0.9 mm
30 m	3.0 mm	2.2 mm	1.1 mm
30 yd (27.4 m)	2.7 mm	2.0 mm	1.0 mm
40 m	4.0 mm	2.9 mm	1.5 mm
45 m	4.5 mm	3.3 mm	1.6 mm
50 m	5.0 mm	3.6 mm	1.8 mm
50 yd (45.7 m)	4.6 mm	3.3 mm	1.7 mm

Two things jump out of that table. One click at air rifle ranges is small — a couple of millimetres — which is why sub-12 ft·lb shooters rarely need more than a handful of clicks to zero. And the difference between turret standards is not trivial: dialling a ¼ MOA correction on a 0.1 MRAD turret puts you about 40% too far out.

Click calculator

Enter the offset of the group centre from the aim point, the distance and your click value. The calculator uses exactly the arithmetic above and rounds to the nearest whole click; anything under half a click is reported as zero, for the reason explained below.

Why "zero clicks" is sometimes the right answer

Go back to that 43 m example. Suppose the windage error is 1.7 mm left. That is 1.7 ÷ 43 = 0.04 MRAD — less than half of one 0.1 MRAD click. If you dial one click right anyway, you move the group 4.3 mm, and now it prints 2.6 mm right of the aim point. You have made the error bigger.

So when the arithmetic rounds to zero, the correct action is to do nothing to that turret. A 1.7 mm error is also comfortably inside the shot-to-shot scatter of any real group at that distance, so it is at least as likely to be noise as a true zero error. Shoot another group before you believe it.

This matters because a lot of zeroing frustration is self-inflicted: dialling tiny corrections back and forth, chasing a centre that was never really off. Knowing when not to touch the turret is as much a part of zeroing as knowing which way to turn it.

How Pellet App does it from one photo

Everything above is doable with a ruler, a calculator and some care. Pellet App exists to remove the ruler, the calculator and most of the care. From a single photograph of the target:

1. It finds the holes. The app detects the pellet holes and tells you how many it found against how many it expected — "5 of 5 holes detected" — with a Mark / Refine Shots control if a torn or overlapping hole needs a hand.
2. It scales the image from the target itself. A printed ruler or a millimetre grid on the card gives it real-world scale, so the millimetres it reports are true millimetres, not screen pixels. Because the reference is on the card, it works on a commercial zeroing target with a printed scale as well as on Pellet's own printables.
3. It measures the group — size in millimetres and in MRAD, with a rating band.
4. It works out the correction. A ZERO CORRECTION — DIAL TO CENTRE panel reports elevation and windage separately, each with a direction arrow and each in three units at once: millimetres, MRAD and scope clicks.

The example numbers on this page are from one of those panels: an elevation correction of 2.7 mm · 0.06 MRAD · 1 click, and a windage correction of 1.7 mm · 0.04 MRAD · 0 clicks, from a five-shot string at 43 m on a commercial zeroing target. That last figure is the point — the app rounds honestly. When the correction is below one click it says zero rather than inventing an adjustment that would move you further from centre.

Before you dial anything

• Were you at your zero distance? A sub-12 ft·lb pellet's trajectory crosses the line of sight twice. A tight group printing low at 15 or 45 yards from a 30-yard zero is correct holdover, not a zero error — dial it out and you've ruined a good zero. How to zero an air rifle scope covers the two-zero trajectory in full.
• Shoot enough shots. Three shots can land almost anywhere by chance; the centre of a five-shot group is a far better estimate of your true point of impact, and ten is better still.
• Read the shape before the offset. A group that strings vertically has a velocity problem, and no number of clicks fixes that. What your group shape tells you goes through the patterns.
• Was it still? A breeze pushes the whole group sideways, and dialling wind into your zero means you'll be off on the next calm day. See reading the wind.
• One correction, then confirm. Dial once, shoot a fresh group, and only then decide whether it needs more. Turret markings are occasionally a little off from their nominal value, and confirming catches that.

Common questions

How many millimetres is one click at 30 metres?

It depends on the turret. A 0.1 MRAD click moves the point of impact 3 mm at 30 m (0.1 mm per metre of range). A ¼ MOA click moves it about 2.2 mm at 30 m (0.073 mm per metre). At 30 yards those become 2.7 mm and 2.0 mm. Check the turret cap or the scope's manual — the click value is printed there.

Which way do I turn the turret to move the group?

Turrets are marked with the direction the point of impact moves — UP on the elevation turret moves the group up, R on the windage turret moves it right. So if the group is printing high, dial down; if it is printing left, dial right. You are moving the group onto the aim point, not the aim point onto the group.

Why does the correction come out as zero clicks?

Because the offset is smaller than half a click. A 1.7 mm error at 43 m is about 0.04 MRAD, and on a 0.1 MRAD turret the nearest whole click is zero. Dialling one click would move the group 4.3 mm — further than the error you were trying to fix. When the maths says zero, the honest answer is to leave the turret alone and shoot another group.

Do I need a special target for Pellet App to work out the clicks?

No. The app takes its scale from a reference printed on the card — a ruler or a millimetre grid — so a commercial zeroing target with a printed scale works. Pellet's own printable targets carry a grid and scale bar for the same reason, but you are not tied to them.