climbing, swimming, and crawling

each foot of movement costs 1 extra foot (2 extra feet in difficult terrain) when you’re climbing, swimming, or crawling

you ignore this extra cost if you have a climbing speed and use it to climb, or a swimming speed and use it to swim

climbing a slippery vertical surface or one with few handholds requires a successful Strength (Athletics) check

gaining any distance in rough water might require a successful Strength (Athletics) check

jumping

your strength determines how far you can jump

long jump

when you make a long jump, you cover a number of feet up to your Strength score if you move at least 10 feet on foot immediately before the jump

when you make a standing long jump, you can leap only half that distance

either way, each foot you clear on the jump costs a foot of movement

this rule assumes that the height of your jump doesn't matter, such as a jump across a stream or chasm

you must succeed on a DC 15 Strength (Athletics) check to clear a low obstacle (no taller than half the jump's distance for the first half and no taller than the remaining distance for the second half), such as a hedge or low wall, to land on your feet

when you land in difficult terrain, you must succeed on a DC 15 Dexterity (Acrobatics) check to land on your feet

if you fail either check, you land prone

when you long jump you go half the distance you jump high, that height plus your height for your size needs to be less than the ceiling

high jump

when you make a high jump, you leap into the air a number of feet equal to 3 + your Strength modifier (minimum of 0 feet) if you move at least 10 feet on foot immediately before the jump

when you make a standing high jump, you can jump only half that distance

either way, each foot you clear on the jump costs a foot of movement

in some circumstances, your DM might allow you to make a Strength (Athletics) check to jump higher than you normally can

you can extend your arms half your height above yourself during the jump, thus, you can reach above you a distance equal to the height of the jump plus your overhead reach for your size

overhead reach

tiny creatures have an overhead reach of 1.875 feet

small creatures have an overhead reach of 3.75 feet

medium creatures have an overhead reach of 7.5 feet

large creatures have an overhead reach of 15 feet

huge creatures have an overhead reach of 30 feet

gargantuan creatures have an overhead reach of 60 feet

using different speeds

if you have more than one speed, such as your walking speed and a flying speed, you can switch back and forth between your speeds during your move

whenever you switch, subtract the distance you've already moved from the new speed, the result determines how much farther you can move

if the result is 0 or less, you can't use the new speed during the current move

for example, if you have a speed of 30 and a flying speed of 60 because a wizard cast the fly spell on you, you could fly 20 feet, then walk 10 feet, and then leap into the air to fly 30 feet more

burrow

a creature that has a burrowing speed can use that speed to move through sand, earth, mud, or ice

a creature cannot burrow through solid rock unless it has a special trait that allows it to do so

climb

a creature that has a climb speed can use all or part of its climb speed to move on vertical surfaces

the creature does not spend extra speed to climb with its climb speed

fly

flying creatures enjoy many benefits of mobility, but they must also deal with the danger of falling

if a flying creature starts its turn with its speed reduced to 0 or otherwise deprived of the ability to move the creature falls unless it has the ability to hover or it is being held aloft by magic, such as by the levitate or fly spell

if a flying creature is knocked prone it must stand as normal on its next turn or fall unless it has the ability to hover or it is being held aloft by magic, such as by the fly spell

swim

a creature that has a swim speed doesn't need to spend extra swim speed to swim

when making a melee weapon attack, a creature that has a swimming speed (either natural or granted by magic) does not have disadvantage on the attack roll unless the weapon is a dagger, javelin, short sword, spear, or trident

a ranged weapon attack automatically misses a target beyond the weapon's normal range, even against a target within normal range, the attack roll has disadvantage unless the weapon is a crossbow, a net, or a weapon that is thrown like a javelin (including a spear, trident, or dart), unless used by a creature with a swim speed

creatures and objects that are fully immersed in water have resistance to fire damage

swim - notes

a swimmer is immune to the prone condition

difficult terrain

combat rarely takes place in bare rooms or on featureless plains

boulder-strewn caverns, briar-choked forests, treacherous staircases — the setting of a typical fight contains difficult terrain

every foot of movement in difficult terrain costs 1 extra foot. This rule is true even if multiple things in a space count as difficult terrain

low furniture, rubble, undergrowth, steep stairs, snow, and shallow bogs are examples of difficult terrain

the space of another creature, whether hostile or not, also counts as difficult terrain

being prone

when combatants find themselves lying on the ground, either because they are knocked down or because they throw themselves down, they are prone

you can drop prone at any time during your turn

you can drop prone at any time during another creature's turn as a reaction

standing up takes more effort; doing so costs an amount of movement equal to half your speed

or example, if your speed is 30 feet, you must spend 15 feet of movement to stand up

you can't stand up if you don't have enough movement left or if your speed is 0

standing up provokes attacks of opportunity

to move while prone, you must crawl or use magic such as teleportation

every foot of movement while crawling costs 1 extra foot

crawling 1 foot in difficult terrain, therefore, costs 3 feet of movement.

moving around other characters

you can move through a non-hostile creature's space as well as through the space of a creature that is unaware of you

you can move through a hostile creature's space only if the creature is at least two sizes larger or smaller than you

remember that another creature's space is difficult terrain for you

if you move when you are in a hostile creature's reach you provoke an opportunity attack, as explained under opportunity attacks

squeezing into a smaller space

a creature can squeeze through a space that is large enough for a creature one size smaller than it

thus, a large creature can squeeze through a passage that's only 5 feet wide

while squeezing through a space, a creature must spend 1 extra foot for every foot it moves there

a squeezing creature has disadvantage on attack rolls (except for melee piercing attacks other than morningstar and war pick plus short and longbow attacks) and dexterity saving throws

attack rolls against a squeezing creature have advantage

creature's space

a creature's space is the area in feet that it effectively controls in combat, not an expression of its physical dimensions

a typical medium creature isn't 5 feet wide, for example, but it does control a space that wide

if a medium creature stands in a 5‐foot-wide doorway, other creatures can't get through unless the creature lets them

a creature's space also reflects the area it needs to fight effectively and it suffers penalties for fighting in a smaller space

for that reason, there's a limit to the number of creatures that can surround another creature in combat

assuming medium combatants, eight creatures can fit in a 5-foot radius around another medium creature

because larger creatures take up more space, fewer of them can surround a smaller creature

size categories

different sized creature takes up a different amounts of space

the size categories table shows how much space a creature of a particular size controls in combat

objects sometimes use the same size categories

Size Categories

tiny creatures take up a 1.25 by 1.25 foot space

small creatures take up a 2.5 by 2.5 foot space

medium creatures take up a 5 by 5 foot space

large creatures take up a 10 by 10 foot space

huge creatures take up a 15 by 15 foot space

gargantuan creatures take up a 20 by 20 foot space

playing on a grid

we play out a combat on Roll20 using a square grid with tokens

Squares

each square on the grid represents 1.25 feet

Speed

rather than moving foot by foot, move square by square on the grid

this means you use your speed in 1.25-foot segments

Entering a Square

to enter a square, you must have enough movement left to enter the square.

Corners

diagonal movement can’t cross the corner of a wall, large tree, or other terrain feature that fills its space

Ranges

to determine the range on a grid between two things—whether creatures or objects—start counting squares from a square occupied by one of them and stop counting in the space of the other one

count by the shortest route

areas of effect

the area of effect of a spell, monster ability, or other feature must be translated onto squares to determine which potential targets are in the area and which aren’t

choose the center of a square as the point of origin of an area of effect, then follow its rules as normal

if an area of effect covers a square, it affects that square

if less than half of a creature's squares are covered by an area effect with a saving throw the creature gets advantage on the saving throw

line of sight

to precisely determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space

if at least one such line doesn’t pass through or touch an object or effect that blocks vision — such as a stone wall, a thick curtain, or a dense cloud of fog — then there is line of sight

determining cover

to determine whether a target has cover against an attack or other effect on a grid, choose a corner of the attacker’s spaces or the point of origin of an area of effect

then trace imaginary lines from that point to every corner of the squares the target occupies

if one of those lines are blocked by an obstacle (including another creature), the target has half cover

if two or three of those lines are blocked the target has three-quarters cover

if four of those lines are blocked but the attack can still reach the target (such as when the target is behind an arrow slit), the target has three-quarters cover and the attacker has disadvantage

flanking

when a creature and at least one of its allies has an enemy in weapon reach and are on opposite sides or corners of the enemy’s space, they flank that enemy, and each of them has advantage on melee attack rolls against that enemy

a creature must be able to melee attack to flank

creature can’t flank an enemy unless it knows it’s location

large or larger creature is flanking as long as at least one square or hex of its space qualifies for flanking

when in doubt about whether two creatures flank an enemy on a grid, trace an imaginary line between the centers of the creatures’ spaces. If the line passes through opposite sides or corners of the enemy’s space, the enemy is flanked

diagonals

when measuring range or moving diagonally on a grid, the first diagonal square counts as 1.25 feet, but the second diagonal square counts as 2.5 feet

this pattern of 1.25 feet and then 5 feet continues whenever you’re counting diagonally

even if you move horizontally or vertically between different bits of diagonal movement

for example, a character might move one square diagonally (2.5 feet), then three squares straight (7.5 feet), and then another square diagonally (5 feet) for a total movement of 15 feet

facing

whenever a creature ends its move, it can chose its facing

each creature has a front arc (the direction it faces), left and right side arcs, and a rear arc

a creature can also change its facing as a reaction when any other creature moves

a creature can normally target only creatures in its front or weapon side arcs, two-handed melee weapons can target both side arcs, and two handed missile weapons are the opposite targeting the front and off side arcs

a creature can’t see into its rear arc, an attacker in the creature’s rear arc, being unseen, makes attack rolls against it with advantage

shields apply their cover bonus to AC only against attacks from the front arc or the same side arc as the shield

for example, a fighter with a shield on the left arm can use it only against attacks from the front and left arcs

not all creatures have every type of arc

for example, an amorphous ochre jelly treats all of its arcs as front ones, while a hydra has three front arcs and one side one

on squares, you pick one side of a creature’s space as the direction it is facing

draw a diagonal line outward from each corner of this side to determine the squares in its front arc

the opposite side of the space determines its rear arc in the same way

the remaining spaces to either side of the creature form its side arcs

a square might be in more than one arc, depending on how you draw the lines from a creature’s space

if more than half of a square or hex lies in one arc, it is in that arc

if it is split exactly down the middle, use this rule

if half of it lies in the front arc, it’s in that arc, if half of it is in a side arc and the rear arc, it’s in the side arc.

a creature can chose to face a corner and so would draw the lines out from the center of each side