The lightning bolt spell creates a 100-foot long, 5-foot wide line of lightning. How tall is this line? Does a creature above the line, not on the ground, take damage because it is still, technically, within the line? The Line entry on PHB 206 isn't helpful, saying nothing about its height.


A line extends from its point of origin in a straight path up to its length and covers an area defined by its width. A line’s point of origin is not included in the line’s area of effect, unless you decide otherwise.


1 Answer 1


A spell's description fully describes its area of effect in three dimensions, so when any dimension is omitted for a non-flat spell effect, that's because it's unnecessary by natural reading and symmetry. So since it's not described as a ribbon or a wall, and since the bolt's width is given as 5 feet, that's the width radially in all directions around the centreline of the line — horizontally, vertically, and diagonally.

When parsing spell descriptions, remember that D&D 5e is written in natural language and doesn't assume a grid (which is an optional rule), so spell descriptions are written assuming the reader will simply picture the most logical natural shape and effects that fit the description, such as “width” being sufficient to describe the other two dimensions of a long thing that isn't already describe as flat or tall.

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    \$\begingroup\$ I believe this is the correct answer, but you should include a citation supporting the assumption in your first sentence. \$\endgroup\$
    – Randomorph
    May 29, 2017 at 22:58
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    \$\begingroup\$ That is not the way I would read it. Perhaps I am being too mathematical here, but if it was meant to be radial, I would expect it to be listed as "diameter" or "radius" (and a five foot radius for this purpose would be very large. I've always envisioned, and still read it, as flat or nearly so with essentially a trivial height. \$\endgroup\$ May 30, 2017 at 0:40
  • \$\begingroup\$ "Thickness" would be far less confusing than "radius" or "diameter" which are used for areas of effect. \$\endgroup\$ May 30, 2017 at 4:32
  • \$\begingroup\$ @TimothyAWiseman We each bring a bit to what we read, and I think SSD is trying to point out the most neutral approach to doing so. \$\endgroup\$ May 30, 2017 at 17:54
  • \$\begingroup\$ Any answer other than this would be quite nonsensical, because it would invite the user or DM to set an arbitrary height. \$\endgroup\$
    – arthexis
    May 30, 2017 at 23:22

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