MOA and MIL are the two languages precision shooters use to talk about the same thing: angle. Not inches, not centimeters — angle. Once that clicks, most of the confusion around scope turrets, reticles, and spotter corrections disappears.
This guide covers what each unit actually is, the math with worked examples, how to correct a miss in both systems, and the one mistake that causes more missed shots than any other.
If you are still choosing an optic, start with our rifle scope buying guide — this article goes deeper on the units themselves.
Why angle, and not inches
A scope adjusts angle, not distance. That is the whole reason these units exist.
If you dial an adjustment, the amount your bullet moves grows with range. The same adjustment that shifts your group one inch at 100 yards shifts it ten inches at 1,000. So “move two inches left” is a meaningless instruction unless everyone knows the distance. “Move half a mil left” works at any range, for any shooter, with any rifle.
That is why spotters call corrections in angular units. It removes the range from the conversation.
MOA: minute of angle
A circle has 360 degrees. Each degree splits into 60 minutes. One MOA is one sixtieth of a degree — a very narrow wedge that widens as it travels.
Run the trigonometry and 1 MOA covers 1.047 inches at 100 yards. Nearly everyone rounds that to one inch, and for most shooting that rounding is harmless. At long range it is not — more on that below.
Most MOA scopes adjust in 1/4 MOA per click, so four clicks move one MOA — about a quarter inch at 100 yards.
MIL: milliradian
A radian is an angle defined by the radius of a circle; there are about 6.28 of them in a full circle. A milliradian is one thousandth of a radian.
The useful property: 1 MIL subtends one unit of whatever you are measuring at one thousand of those units in distance. One meter at 1,000 meters. One yard at 1,000 yards. Ten centimeters at 100 meters.
In inches at 100 yards, 1 MIL is exactly 3.6 inches — because 100 yards is 3,600 inches, and a thousandth of that is 3.6.
Most MIL scopes adjust in 0.1 MIL per click, so ten clicks move one MIL.
The numbers side by side
| Distance | 1 MOA covers | 1 MIL covers |
|---|---|---|
| 100 yd | 1.05 in | 3.60 in |
| 200 yd | 2.09 in | 7.20 in |
| 300 yd | 3.14 in | 10.80 in |
| 500 yd | 5.24 in | 18.00 in |
| 800 yd | 8.38 in | 28.80 in |
| 1,000 yd | 10.47 in | 36.00 in |
The conversions worth memorizing:
- 1 MIL = 3.44 MOA
- 1 MOA = 0.29 MIL
A MIL is the coarser unit — roughly three and a half times bigger than a MOA. That matters for adjustment resolution, which we will come back to.
Worked example: correcting a miss
You are shooting at 400 yards. Your shot lands 8 inches low. How much do you dial?
In MOA
First, what does 1 MOA cover at 400 yards? Four times the 100-yard value:
- 1.047 × 4 = 4.19 inches per MOA
- 8 ÷ 4.19 = 1.91 MOA of correction needed
- At 1/4 MOA per click: 1.91 × 4 = 7.6 clicks
- Round to 8 clicks up (2.00 MOA)
In MIL
Same process. What does 1 MIL cover at 400 yards?
- 3.6 × 4 = 14.4 inches per MIL
- 8 ÷ 14.4 = 0.56 MIL of correction needed
- At 0.1 MIL per click: 5.6 clicks
- Round to 6 clicks up (0.6 MIL)
Both land you in the same place. Neither is harder — but notice that the MOA solution needed a decimal that does not divide cleanly, while the MIL solution is base-10 throughout. That difference compounds when you are doing it quickly, in wind, under a time limit.
Worked example: ranging with the reticle
This is where MIL earns its reputation. If you know a target’s size and can measure it in your reticle, you can calculate range.
Say a target is 20 inches tall and measures 1.5 MIL in your reticle.
The MIL formula
Range (yards) = (target size in inches ÷ mils) × 27.78
(20 ÷ 1.5) × 27.78 = 13.33 × 27.78 = 370 yards
In metric it is cleaner still, because the units cancel: Range (m) = (target size in mm) ÷ mils ÷ 1000, or simply size in meters ÷ mils × 1000.
The MOA formula
That same target measures 5.16 MOA (1.5 × 3.44).
Range (yards) = (target size in inches × 95.5) ÷ MOA
(20 × 95.5) ÷ 5.16 = 1,910 ÷ 5.16 = 370 yards
Identical answer, as it must be — it is the same angle. But the MOA version needs a constant of 95.5 that has no intuitive meaning, while the MIL version uses 27.78 and drops away entirely in metric.
Important: reticle ranging only works if the reticle subtensions are correct at the magnification you are using. On a second focal plane scope they are only true at one setting, usually maximum. On a first focal plane scope they are true at every magnification — which is why serious ranging work is done on FFP optics. See the scope buying guide for that distinction.
The “one inch at 100 yards” shortcut, and where it breaks
Treating MOA as exactly one inch per hundred yards is fine at short range. The error is under half an inch at 1,000 yards for a single MOA — invisible.
The problem is that elevation adjustments at distance are not one MOA. They are twenty or thirty, and the error scales with them:
| Dialed at 1,000 yd | True movement | Assuming 1 in/100 yd | Error |
|---|---|---|---|
| 10 MOA | 104.7 in | 100 in | 4.7 in |
| 20 MOA | 209.4 in | 200 in | 9.4 in |
| 30 MOA | 314.2 in | 300 in | 14.2 in |
Fourteen inches is a miss on most targets worth shooting at. Some scopes are actually built to the rounded value — sometimes called IPHY, or “inch per hundred yards” — which is a genuinely different unit from true MOA. If your dope is not matching your scope at distance, this is one of the first things to check.
MIL has no equivalent trap. A milliradian is defined by the geometry and there is no convenient rounding to tempt anyone.
Adjustment resolution
One real, measurable difference: MOA scopes adjust in finer increments.
| Click value | At 100 yd | At 1,000 yd |
|---|---|---|
| 1/4 MOA | 0.26 in | 2.62 in |
| 0.1 MIL | 0.36 in | 3.60 in |
A quarter-MOA click is about a third finer than a tenth-MIL click. In practice this matters far less than it looks: at 1,000 yards the difference between the two is one inch, which is well inside the dispersion of the rifle, the ammunition, and the wind you did not read perfectly.
Do not choose a system over one inch at 1,000 yards.
The mistake that actually costs shots
Mismatching your reticle and your turrets.
A MIL reticle with MOA turrets is a functioning scope and a broken system. You see a miss as 0.5 MIL in the reticle, then have to convert — 0.5 × 3.44 = 1.72 MOA — then convert again to clicks — 1.72 × 4 = 6.9, call it 7 clicks. Two conversions and a rounding decision, under time pressure, for information the reticle already handed you.
Matched, it is trivial: you see 0.5 MIL low, you dial 5 clicks of 0.1 MIL. No arithmetic at all. The reticle and the turret speak the same language, and holding over becomes as valid as dialing.
Mixed scopes still exist on the used market. Check before you buy.
Pros and cons, side by side
MOA
In its favour:
- Finer adjustment. A 1/4 MOA click moves 0.26 in at 100 yd against 0.36 in for 0.1 MIL — roughly a third finer.
- Intuitive if you already think in inches and yards. About an inch at a hundred is a mental model most American shooters carry already.
- Fits imperial targets. Group sizes, target dimensions, and most US published data are in inches to begin with.
- Huge installed base. Decades of hunting optics, load data, and rifle accuracy claims are quoted in MOA.
- Finer reticle graduations on some designs, useful for precise holds at a known distance.
Against it:
- The math is not base-10. Four clicks to the unit, and corrections rarely land on whole numbers.
- The 1.047 problem. The convenient rounding is wrong, and the error scales with how much you dial — 14 in at 1,000 yd on a 30 MOA adjustment.
- IPHY confusion. Some scopes are built to the rounded value, which is a different unit wearing the same name.
- More clicks to count. A large elevation change means tracking a lot of quarter-minutes.
- Not the common language in precision and tactical circles, so spotters, match data, and many drop charts need converting.
MIL
In its favour:
- Base-10 throughout. Ten clicks to the mil, decimals everywhere, and mental arithmetic that holds up under pressure.
- No rounding trap. A milliradian is exactly what the geometry says, with no tempting approximation to get wrong.
- Cleaner ranging math — and in metric the units cancel entirely: size in meters, divided by mils, times 1,000.
- It is the common language. Spotters, competitors, ballistic apps, and most modern precision optics default to mils, so corrections transfer without translation.
- Fewer numbers to hold in your head: 0.6 mil rather than 2.5 MOA and nine clicks.
Against it:
- Coarser clicks. 0.36 in at 100 yd against 0.26 in — real, though it vanishes inside normal dispersion at distance.
- Less intuitive in inches. A tenth of a mil means nothing physical until you convert, which is awkward when zeroing on an imperial target.
- A learning curve if every rifle you own and every chart you have built is already in MOA.
- Slightly coarser for fine zeroing at 100 yd, where one click is a larger share of the adjustment you want.
- Mixed shooting groups. If your usual partners call corrections in MOA, being the only mil shooter creates friction.
Read those lists together and a pattern emerges: almost every MOA advantage is about familiarity, and almost every MIL advantage is about arithmetic. That is the real decision — whether you value the system you already think in, or the one that asks less of you when the shot matters.
So which should you use?
Neither is more accurate. They measure the same angles with different rulers.
- Choose MIL if you shoot with partners or a spotter, compete, use ballistic apps, or want the base-10 math. It is the dominant language in precision and tactical shooting, and being fluent in what everyone else speaks has real value.
- Choose MOA if you think natively in inches and yards, shoot mostly alone, or already own MOA optics and dope. The finer clicks are a mild bonus.
The genuinely important part: pick one and commit. Fluency beats the theoretical advantages of either. A shooter who thinks in mils without converting will out-shoot one who is doing arithmetic on every correction — and if you run more than one rifle, keeping them all in the same system means your instincts transfer.
The third option: let the optic do the math
Everything above assumes you are the ballistic computer. There is another path: optics that range the target and calculate the solution for you.
The Burris Eliminator series is the best known. It combines a riflescope, a laser rangefinder, and an onboard ballistic computer in one unit. You program it with your load data once, then in the field you press a button: it ranges the target, computes the drop, and illuminates an aiming point in the reticle. You put the lit dot on the animal and press the trigger.
The line has gone through several generations. The Eliminator V and the newer Eliminator VI are the current ones, with the later generation extending effective ranging distance and adding wind holds alongside the elevation solution. If you are comparing them, the practical questions are how far each will reliably range on the game you hunt, and whether you want the wind guidance.
No dialing, no holdover math, no MOA or MIL arithmetic at all. For a hunter who takes a handful of shots a year at unpredictable distances — which describes most hunters — that removes the exact failure point where things go wrong: doing arithmetic quickly, under pressure, on an animal that will not wait.
What you give up
- It only knows what you told it. The solution is exactly as good as the ballistic data you programmed. Wrong velocity or the wrong bullet profile produces a confident, precise miss.
- Batteries. A dead optic on a hunt is a scope you cannot use as intended — and battery life suffers in cold, which is when you are most likely to be hunting.
- Weight and cost. Meaningfully heavier and more expensive than a conventional scope of similar magnification.
- It does not teach you anything. If it fails, or you borrow a rifle, or you shoot past its range, you still need to understand the fundamentals in this article.
- Not competition legal in many disciplines, and worth checking against the rules of anything you shoot.
Honest assessment: it is an excellent hunting tool and a poor learning tool. If you hunt open country and want the fastest correct answer on an unrepeatable shot, it earns its money. If you are building long-range skill, learn to range and dial first — then decide whether you want the shortcut.
A middle path worth knowing: a separate laser rangefinder plus a ballistic app on your phone gives you most of the same capability, keeps a conventional scope, and costs less — at the price of an extra step and another device.
Common questions
Is MIL metric and MOA imperial?
No — this is the most common misconception. Both are pure angular units and work in any measurement system. MIL simply looks metric because the math is base-10 and it happens to be very tidy in meters and centimeters.
What does a “1 MOA rifle” mean?
That it groups inside roughly one MOA — about 1.05 inches at 100 yards, 2.1 at 200, and so on. It is a claim about the rifle’s dispersion, not about the scope.
Should I dial or hold over?
Dial for known, deliberate distances. Hold for speed and for targets appearing at varied ranges. A matched reticle and turret system lets you do either without converting anything.
Do I need to memorize the conversion?
If your equipment is matched, no — you will rarely convert. Knowing that 1 MIL is about 3.44 MOA is useful mainly for reading other people’s data.
Where to start
Buy a scope whose reticle and turrets match, in whichever system you intend to learn, and then build a dope chart in that system and stop converting. First focal plane if you plan to range or hold with the reticle.
Browse rifle scopes and optics, read the scope buying guide for magnification and mounting, or see our comparison of the best long range rifle calibers if you are still building the rifle.
Note: optics, electronic sights, and illumination devices are final sale and cannot be returned — see our returns policy. Ask us before you order if you are unsure which system suits your shooting.