Scope Ring Height Calculator: Rings to Sight Height
This scope ring height calculator turns your objective diameter and tube size into the sight height your ballistics need. Ring height is the gap between the rail and the scope tube.
Ring height is the gap between the rail and the scope, and two makers measure it from two different places. One measures to the center of the tube, the other to the bottom of it.
The difference between those two bases is one tube radius — 0.500 in on a 1-inch tube, 0.591 in on a 30 mm one. That is larger than the entire gap between a low ring and a high ring at most makers. Put a number measured one way into a chart built the other way and a fit becomes a non-fit, or worse, a bell that touches the barrel. This calculator asks which basis you are working in and answers on both.
Scope ring height calculator
Worked example, no script required. These are the numbers the calculator starts on, so a reader with scripts turned off sees exactly what a reader with them on sees. A 2.280 in bell on a 1 inch tube with 0.100 in of clearance needs a ring measuring 1.240 in on the center basis, which is the same ring measuring 0.740 in on the underside basis. On a rifle whose bore axis sits 0.900 in below the rail, that is a sight height over bore of 2.140 in.
Which basis does your ring maker use?
We checked each maker against its own page on 2026-08-25 and recorded what it says, not what the industry assumes it says. Makers appear in the block for the basis they state. No table below mixes two bases in one column, because two numbers measured from different places are not comparable and printing them side by side is how the mistake gets made.
Rail top to the optical center
| Maker | What the maker publishes | Words we matched against the maker’s own bytes |
|---|---|---|
| EGW | 1 in rings: .850 Low, .990 Medium, 1.275 High | we measure from the highest point on the Picatinny or Weaver rail to the dead center of where the scope will sit source EGW states the basis in prose and is the only source retrieved that names the split itself. |
| Scalarworks | LEAP/08 SW0810: 1.57 in | Optic center height over rail source The spec line is literally titled optic center height over rail. |
| Burris | Published per part in a column headed Height to Center | Ring Height Height to Center source Burris carries a named category AND a separate numeric height-to-center column, so its number cannot be mistaken for a clearance figure. |
Rail top to the underside of the tube
| Maker | What the maker publishes | Words we matched against the maker’s own bytes |
|---|---|---|
| Warne | Low rings measure between .250 and .275 in | Or = Objective Radius Tr = Tube Radius Bh = Base or rail height measured at the front of the receiver Mrh = Minimum ring height source Warne’s published formula subtracts the tube radius, so the figure it produces is rail-top to the underside of the tube, not to the optical center. |
The maker does not state a basis
| Maker | What the maker publishes | Words we matched against the maker’s own bytes |
|---|---|---|
| Leupold | None. The chart maps objective size to a category name only. | FIT RING HEIGHT TO OBJECTIVE DIAMETER source Leupold’s own ring-height chart publishes no numeric height and no basis. |
| Seekins Precision | 30 mm: 0.82 Low, 0.87 Medium, 0.97 High, 1.26 X-High | 30mm — 0.82” Low source Seekins publishes numbers but no basis on the rings page retrieved, so its figures cannot be placed in a column with anyone else’s. |
4 of the 6 makers we could retrieve state a basis at all. EGW is the only one that names the problem out loud: “A “Low” from one company might be a “Medium” from another”. Leupold’s own ring-height chart, the document the whole industry links to, publishes no numeric height and no basis — it maps an objective size to the words low, medium or high and stops there.
How far apart are the two answers?
Exactly one tube radius, every time. It is not an estimate.
| Tube | Tube diameter | Difference between the two bases |
|---|---|---|
| 1 inch | 1.000 in | 0.500 in |
| 30 mm | 1.181 in | 0.591 in |
| 34 mm | 1.339 in | 0.669 in |
| 35 mm | 1.378 in | 0.689 in |
| 40 mm | 1.575 in | 0.787 in |
Warne publishes a low 30 mm ring at “our low rings measure between .250 and .275 depending on which style”. EGW publishes a low 1-inch ring at “1-Inch Keystone Rings .850” Low .990” Medium 1.275” High”. Those are not a disagreement about rings. They are two different measurements of the same kind of part.
The arithmetic, in full
Write the objective bell radius as Ro, the tube radius as Rt and the clearance you want under the bell as C, all in inches.
Ring height on the center basis equals Ro plus C.
Ring height on the underside basis equals Ro plus C minus Rt.
Sight height over bore equals the center-basis ring height plus the distance from the bore axis to the top of the rail.
Warne publishes its own version of the first step, and it is worth reading because it shows the basis in the algebra: “Or minus Tr minus Bh = Mrh”, where “Or = Objective Radius Tr = Tube Radius Bh = Base or rail height measured at the front of the receiver Mrh = Minimum ring height”. The tube radius is subtracted, so the figure that comes out is not a distance to the optical center.
Sight height over bore, and why this page ends here
Ring height is a fitting question. Sight height over bore is a shooting question, and it is the one that follows you downrange. It is the figure a ballistic solution takes as an input, and it is the number this tool exists to hand to the rest of the site.
How much does getting it wrong cost you? Less than most people say, and by a knowable amount. Hold the zero fixed at Z. A change of d inches in sight height moves the path at range x by d times (x over Z minus 1). At the zero itself it moves nothing. Inside the zero it moves the other way.
Worked against this network’s own solver: 0.9 in of sight height moves the 300-yard path 0.450 in on a 200-yard zero — half the sight-height difference, not all of it. A shooter who believes it is the full difference will write off a real gap between two loads as an artefact of their scope rings.
Two ways to get the number. If you know how far the bore axis sits below the top of the rail, add it to the center-basis ring height and you are done. If you do not, measure it on the rifle: half the barrel diameter at the point you measure, plus the gap from the top of the barrel to the bottom of the tube, plus half the tube diameter. Both give the same figure and neither needs a database of rifles.
Take the result to the GGD ballistic calculator, which asks for sight height over bore directly, or to the caliber pages — 350 Legend, 450 Bushmaster, 6.5 PRC and 22 ARC — each of which prints the sight height its published trajectories assume, because the makers do not all assume the same one.
Questions this scope ring height calculator answers
- How do you measure scope height?
- Measure from the center of the bore to the center of the scope tube. In practice: half the barrel diameter, plus the gap between the top of the barrel and the bottom of the tube, plus half the tube diameter. That is sight height over bore, and it is not the same number as ring height.
- Is ring height measured to the center of the scope or the bottom?
- Both, depending on who made the ring. EGW, Scalarworks and Burris publish a figure measured to the optical center. Warne’s published formula subtracts the tube radius, so its figure is not a center figure. Leupold and Seekins do not state a basis on the pages we retrieved.
- What ring height do I need for a 50 mm objective?
- It depends on the bell, not the lens. Put the bell outside diameter into the calculator above with the clearance you want. A 2.280 in bell wanting 0.100 in of clearance needs 1.240 in to the optical center.
- Does ring height change my zero?
- It changes the path, not the zero. You can zero at any height. What changes is how far the bullet sits from the line of sight everywhere else, by the sight-height difference times the range divided by the zero, minus one.
- Why do two makers call the same ring low and medium?
- Because there is no standard. EGW says so on its own page: the difference comes down to how each company measures. Compare the numbers and the basis, never the names.
Sources for the basis register
Each row was fetched from the named company on 2026-08-25 and the quote matched against the bytes returned. Where a source is a dealer rather than the manufacturer, it is labelled as one and its claim is recorded as the dealer’s.
| Maker | Stated basis | Source | Retrieved |
|---|---|---|---|
| EGW | Rail top to the optical center | egwguns.com | 2026-08-25 |
| Scalarworks | Rail top to the optical center | scalarworks.com | 2026-08-25 |
| Burris | Rail top to the optical center | www.burrisoptics.com | 2026-08-25 |
| Warne | Rail top to the underside of the tube | warnescopemounts.com | 2026-08-25 |
| Leupold | The maker does not state a basis | www.leupold.com | 2026-08-25 |
| Seekins Precision | The maker does not state a basis | seekinsprecision.com | 2026-08-25 |
Who is missing, and why
These companies are absent because their sites refused retrieval to this build on 2026-08-25. An absence here is a fact about the fetch and not a claim about the product. None of it should be read as a claim that they publish no ring heights.
| Company | What the fetch returned |
|---|---|
| Vortex Optics | HTTP 406 on every product page tried |
| Talley Manufacturing | HTTP 202 with a 190-byte challenge body |
| American Rifle Company | connection failed |
| Nightforce Optics | no rings page reachable; the site publishes no XML sitemap and every rings path tried returned HTTP 404 |
Where to go next
Data updated September 2026.
- GGD ballistic calculator — takes sight height over bore as an input.
- Pistol optic footprint chart — the mounting-pattern half of the same problem.
- How we compute ballistics — the solver the sensitivity figure above was checked against.
- Firearm glossary.
How this page is maintained. The arithmetic is definitional and does not expire. The basis register is reviewed annually and whenever a maker publishes or withdraws a stated basis. Last verified against every source above on 2026-08-25.