Impact Energy & Crater Calculator

How this is worked out

Kinetic energy follows directly from the impactor's mass (from its diameter and density) and speed: E = ½mv². Crater size uses the scaling laws from Collins, Melosh & Marcus (2005), the model behind the widely-used "Earth Impact Effects Program": first the transient crater (the cavity excavated in the first moments of impact) from the impactor's diameter, density, speed and impact angle relative to the target's density and gravity, then a conversion to final crater diameter that depends on whether the result is a smaller "simple" bowl-shaped crater or a larger "complex" crater with a central peak and collapsed walls (the transition happens at about 3.2 km on Earth, for rock).

This is an approximate scaling-law model, not a precise simulation — real craters are also shaped by local geology, so treat the result as an order-of-magnitude estimate. It isn't valid for the very largest basin-forming impacts (multi-ring structures like Chicxulub), where the physics changes further.

Frequently asked questions

How does this compare to Meteor Crater, Arizona?

With this tool's defaults (a 50 m iron impactor at 12.8 km/s, 45°, into sedimentary rock) the energy comes out at about 10 megatons of TNT and the estimated final crater at roughly 1.5 km — in the right range of, if somewhat larger than, Meteor Crater's actual 1.19 km diameter (some of that gap is expected: the real crater has also been softened by about 50,000 years of erosion and infill, which this model doesn't account for).

Why does impact angle matter?

A shallower, more glancing impact (smaller angle from horizontal) spreads the same kinetic energy over a larger area and couples less of it efficiently into excavating a crater, so it produces a smaller crater than a steeper, more direct hit at the same speed and size.

Related tools: Asteroid Diameter from Magnitude Calculator, Orbital & Escape Velocity Calculator, Planet Facts Table.

Source / Last verified: Collins, G. S., Melosh, H. J., & Marcus, R. A. (2005), "Earth Impact Effects Program", Meteoritics & Planetary Science, 40(6), 817–840 — the transient- and final-crater formulas as reproduced (with full citation) in later published studies using the same model, read 1 October 2026, since the original paper's own PDF could not be extracted as readable text. This is explicitly an approximate model (the authors' own caveat); this tool's estimate for Meteor Crater, Arizona is in the right order of magnitude (within about 30%) of the real, eroded crater, consistent with what a scaling-law estimate like this should achieve. Estimate only, not a precise prediction.