Secret Lesson 19

Movement and Position: Speed, Difficult Terrain, Spaces, and Creatures

You now know when every combatant acts.

The next question is:

WHERE CAN THEY GO?

Position is a fundamental part of combat.

Where your character stands can determine:

  • which enemies you can reach

  • which enemies can reach you

  • whether you can escape

  • whether terrain slows you down

  • whether another creature blocks your path

  • how far you can move before acting

  • where you finish your turn

The SRD organizes these ideas under:

MOVEMENT AND POSITION

On your turn, you can move a distance equal to your Speed or less.

You may also choose:

NOT TO MOVE AT ALL

 

SPEED IS YOUR MOVEMENT LIMIT

Your:

SPEED

represents how far you can normally move during your turn.

If your Speed is:

30 feet

you can move anywhere from:

0 feet

to:

30 FEET

during the turn.

You are not required to use all of it.

EXAMPLE

Speed:

30 feet

You move:

20 feet

You may stop there.

You don't have to move the remaining 10 feet.

CHARACTER SPEED VS. MONSTER SPEED

For a player character, Speed is determined during:

CHARACTER CREATION

For a monster, its Speed appears in:

ITS STAT BLOCK

 

Different creatures can therefore move at different rates.

MOVEMENT IS NOT AN ACTION

Your movement and your Action are separate parts of your turn.

Normally, you can:

MOVE UP TO YOUR SPEED

and:

TAKE ONE ACTION

You can choose which happens first.

For example:

OPTION A

Move → Attack

OPTION B

Attack → Move

YOU CAN BREAK UP YOUR MOVEMENT

You don't have to use all your movement at once.

The SRD allows you to divide it before and after:

  • an Action

  • a Bonus Action

  • a Reaction taken on your own turn

 

EXAMPLE

Speed:

30 feet

You move:

10 feet

Then:

Attack

Then move:

20 feet

Total movement:

30 FEET

This is completely valid.

ANOTHER EXAMPLE

Speed:

40 feet

You move:

15 feet

Use a Bonus Action.

Move:

10 feet

Take your Action.

Move:

15 feet

Total:

15 + 10 + 15 = 40 feet

You have used your full Speed.

MOVEMENT IS A POOL OF DISTANCE

A useful way to understand Speed is as a movement allowance for the turn.

If you have:

SPEED 30 FEET

and move:

12 feet

you have:

18 feet

remaining.

Move another:

8 feet

Remaining:

10 feet

Continue until:

  • you stop voluntarily

  • or you use the available movement

The SRD says to deduct the distance of each part of your movement until your Speed is used up or you decide you are finished.

DIFFERENT TYPES OF MOVEMENT

Movement can include:

  • normal movement

  • climbing

  • crawling

  • jumping

  • swimming

These can be combined during your move or can make up the entire move.

EXAMPLE — COMBINING MOVEMENT

Suppose you have:

Speed 30 feet

You might:

walk 10 feet

then:

climb

then continue moving,

provided you correctly pay the movement costs for each part.

SPECIAL SPEEDS

Some creatures possess special speeds such as:

CLIMB SPEED

FLY SPEED

SWIM SPEED

The SRD points to the Rules Glossary for their detailed definitions.

For now, the important principle is:

DIFFERENT MOVEMENT MODES STILL CONSUME MOVEMENT

according to the rules governing that mode.

CLIMBING

Without using a Climb Speed, climbing normally costs extra movement.

The SRD states:

EACH FOOT OF CLIMBING COSTS 1 EXTRA FOOT

So moving:

5 feet upward

normally costs:

10 FEET OF MOVEMENT

If the area is also Difficult Terrain, climbing costs still more. A creature using a Climb Speed ignores the normal extra climbing cost.

CRAWLING

Crawling follows a similar rule.

Each foot crawled costs:

1 EXTRA FOOT

So:

5 feet of crawling

normally costs:

10 feet of movement

In Difficult Terrain, the cost increases further.

SWIMMING

Swimming normally costs:

1 EXTRA FOOT PER FOOT MOVED

unless you have and use an appropriate Swim Speed.

So:

5 feet of ordinary swimming

normally costs:

10 feet of movement

 

DIFFICULT TERRAIN

Combat environments aren't always smooth and empty.

Examples from the combat section include:

  • low furniture

  • rubble

  • undergrowth

  • steep stairs

  • snow

  • shallow bogs

These can count as:

DIFFICULT TERRAIN

 

HOW DIFFICULT TERRAIN WORKS

In Difficult Terrain:

EVERY FOOT OF MOVEMENT COSTS 1 EXTRA FOOT

So moving:

5 FEET

through Difficult Terrain costs:

10 FEET OF MOVEMENT

 

EXAMPLE

Speed:

30 feet

You move entirely through Difficult Terrain.

Every 5 feet costs:

10 feet of movement

Therefore, with 30 feet of available movement, you can physically travel:

15 FEET

through that terrain.

DIFFICULT TERRAIN DOES NOT STACK WITH ITSELF

This is extremely important.

The SRD states:

DIFFICULT TERRAIN IS NOT CUMULATIVE

A space either:

is Difficult Terrain

or:

is not Difficult Terrain.

EXAMPLE

A space contains:

  • heavy snow

  • rubble

  • undergrowth

All three could make it Difficult Terrain.

But you do not calculate:

double + double + double movement cost

because multiple reasons for Difficult Terrain don't stack.

The space is simply:

DIFFICULT TERRAIN

WHAT CAN MAKE A SPACE DIFFICULT TERRAIN?

The Rules Glossary provides examples.

A space can be Difficult Terrain if it contains:

  • a creature that isn't Tiny or your ally

  • furniture sized for creatures of your Size or larger

  • heavy snow

  • ice

  • rubble

  • undergrowth

  • liquid between shin and waist depth

  • a narrow opening sized for a creature one Size smaller than you

  • a slope of 20 degrees or more

 

CREATURES CAN CREATE DIFFICULT TERRAIN

This is especially important in combat.

Another creature's space can slow you down.

The combat rules state that another creature's space is Difficult Terrain for you unless that creature is:

TINY

or:

YOUR ALLY

 

But whether you are actually allowed to pass through that creature's space is a separate question.

We will address that shortly.

DROPPING PRONE

On your turn, you can voluntarily give yourself the:

PRONE CONDITION

without spending:

  • an Action

  • any of your Speed

However:

YOU CANNOT DO THIS IF YOUR SPEED IS 0

 

EXAMPLE

You want to drop behind a low obstruction.

On your turn:

DROP PRONE

This costs:

0 movement

and:

no Action

provided your Speed isn't 0.

The Prone condition itself has additional effects.

STANDING UP FROM PRONE

Once Prone, your movement options are restricted.

You can:

CRAWL

or spend movement equal to:

HALF YOUR SPEED, ROUNDED DOWN

to right yourself and end the Prone condition.

If your Speed is:

0

you cannot right yourself.

EXAMPLE — STANDING

Speed:

30 feet

Half:

15 FEET

You spend:

15 feet of movement

to stand.

Remaining movement:

15 FEET

EXAMPLE — SPEED 25

Speed:

25 feet

Half:

12.5

Round down:

12 FEET

That is the movement cost to right yourself under the Prone condition's rule.

CREATURE SIZE

Every creature belongs to a:

SIZE CATEGORY

The categories range from:

TINY

to:

GARGANTUAN

 

A creature's Size helps determine:

THE SPACE IT OCCUPIES ON A MAP

CREATURE SIZE AND SPACE TABLE

Size Space in Feet Grid Space
Tiny 2½ × 2½ ft. 4 per square
Small 5 × 5 ft. 1 square
Medium 5 × 5 ft. 1 square
Large 10 × 10 ft. 4 squares, 2 × 2
Huge 15 × 15 ft. 9 squares, 3 × 3
Gargantuan 20 × 20 ft. 16 squares, 4 × 4

 

SMALL AND MEDIUM CREATURES

Both:

SMALL

and:

MEDIUM

creatures normally occupy:

ONE 5-FOOT SQUARE

Even though their physical bodies can differ in size.

LARGE CREATURE

A Large creature occupies:

10 × 10 FEET

On a grid:

2 × 2 SQUARES

That means four squares total.

HUGE CREATURE

A Huge creature occupies:

15 × 15 FEET

or:

3 × 3 SQUARES

Nine squares total.

GARGANTUAN CREATURE

A Gargantuan creature occupies:

20 × 20 FEET

or:

4 × 4 SQUARES

Sixteen squares total.

TINY CREATURES

Tiny creatures have a particularly small space:

2½ × 2½ FEET

The table represents this as:

FOUR TINY CREATURES PER 5-FOOT SQUARE

 

A CREATURE'S SPACE IS NOT JUST ITS BODY

The SRD describes a creature's space as the area it:

EFFECTIVELY CONTROLS IN COMBAT

and the area it needs to fight effectively.

So a Medium creature does not literally have a body five feet wide.

The 5-foot space represents the area required for:

  • movement

  • stance

  • weapon use

  • defensive movement

  • combat control

WHERE DOES CHARACTER SIZE COME FROM?

A player character's Size is normally determined by:

SPECIES

A monster's Size appears in:

ITS STAT BLOCK

 

We will cover character Size in more detail during character creation.

MOVING THROUGH ANOTHER CREATURE'S SPACE

Combatants often stand between you and where you want to go.

You cannot automatically move through every occupied space.

The SRD allows you to pass through the space of:

AN ALLY

AN INCAPACITATED CREATURE

A TINY CREATURE

or:

A CREATURE TWO SIZES LARGER OR TWO SIZES SMALLER THAN YOU

 

ALLIES

You can move through:

AN ALLY'S SPACE

For example:

your Fighter can move through the square occupied by another party member.

INCAPACITATED CREATURES

You can pass through the space of a creature with the:

INCAPACITATED CONDITION

regardless of normal hostile positioning restrictions, subject to the rest of the movement rules.

TINY CREATURES

You can pass through the space of:

A TINY CREATURE

 

Its extremely small Size makes it less capable of physically blocking your route under this rule.

CREATURES TWO SIZES DIFFERENT

You can pass through a creature if it is:

TWO SIZES LARGER

or:

TWO SIZES SMALLER

than you.

SIZE EXAMPLE — MEDIUM VS. HUGE

You are:

MEDIUM

The enemy is:

HUGE

The Size steps are:

Medium → Large → Huge

The Huge creature is:

TWO SIZES LARGER

Therefore:

you can pass through its space under this rule.

MEDIUM VS. LARGE

You are:

Medium

Enemy:

Large

That is only:

ONE SIZE DIFFERENCE

The “two sizes larger or smaller” permission does not apply.

If no other permission exists, you cannot simply move through that enemy's space.

LARGE VS. TINY

A Large creature can pass through a Tiny creature's space because:

TINY CREATURES ARE SPECIFICALLY ALLOWED

You don't need to rely only on the two-size difference rule.

PASSING THROUGH DOES NOT ALWAYS MEAN NORMAL TERRAIN

Even when you are allowed to move through another creature's space, that space can still count as:

DIFFICULT TERRAIN

The combat rules state:

ANOTHER CREATURE'S SPACE IS DIFFICULT TERRAIN UNLESS THAT CREATURE IS TINY OR YOUR ALLY

 

EXAMPLE — HUGE ENEMY

You are Medium.

Enemy is Huge.

You are permitted to move through its space because it is two Sizes larger.

But the enemy is:

  • not Tiny

  • not your ally

Therefore its space is:

DIFFICULT TERRAIN

for you.

EXAMPLE — ALLY

Your ally occupies a square.

You can pass through the ally's space.

Because the creature is your ally:

the creature-space rule does not make that space Difficult Terrain.

EXAMPLE — TINY ENEMY

A hostile Tiny creature occupies the space.

You may pass through it.

And because it is:

TINY

its space isn't Difficult Terrain for you under this creature-space rule.

YOU NORMALLY CANNOT END YOUR MOVE IN ANOTHER CREATURE'S SPACE

Even when you can pass through a creature's space:

YOU CANNOT WILLINGLY END YOUR MOVE THERE

 

This is an important distinction:

PASS THROUGH ≠ STOP THERE

EXAMPLE

You move through your ally's square.

Allowed.

But you cannot normally say:

“I finish my move in the exact same space as my ally.”

You must continue to another valid space.

WHAT IF YOU SOMEHOW END THE TURN IN ANOTHER CREATURE'S SPACE?

Sometimes an effect or unusual circumstance causes two creatures to end up occupying the same space.

If you end your turn sharing another creature's space:

YOU HAVE THE PRONE CONDITION

unless:

YOU ARE TINY

or:

YOU ARE LARGER THAN THE OTHER CREATURE

 

EXAMPLE — TWO MEDIUM CREATURES

You are:

Medium

The other creature is:

Medium

An effect somehow causes you to end your turn in its space.

You are neither:

  • Tiny

  • larger than it

Therefore:

YOU BECOME PRONE

EXAMPLE — LARGE WITH MEDIUM

You are:

Large

Other creature:

Medium

You somehow end your turn in its space.

Because you are:

LARGER THAN THE OTHER CREATURE

the special Prone consequence doesn't apply to you.

EXAMPLE — TINY CREATURE

You are:

Tiny

You somehow end your turn sharing another creature's space.

The rule specifically exempts:

TINY CREATURES

from this Prone consequence.

MOVEMENT AND OPPORTUNITY ATTACKS

Moving around enemies can sometimes trigger:

OPPORTUNITY ATTACKS

That mechanic is important enough to receive detailed treatment in:

LESSON 22

For now, understand that:

BEING ABLE TO MOVE THROUGH OR AWAY FROM A SPACE DOES NOT NECESSARILY MEAN DOING SO IS SAFE.

The movement rules tell you where you can move.

Other combat rules may determine what happens because you moved.

DISENGAGE AND MOVEMENT

You already learned the:

DISENGAGE ACTION

If you take Disengage:

your movement does not provoke Opportunity Attacks for the rest of that turn.

We will connect this fully to melee combat later.

COMPLETE MOVEMENT EXAMPLE

Character:

Medium

Speed:

30 FEET

The character begins 25 feet from a target.

Between them are:

  • 10 feet of normal ground

  • 10 feet of Difficult Terrain

  • 5 feet of normal ground

Movement cost:

First 10 feet

Normal:

10 movement

Remaining:

20

Next 10 feet

Difficult Terrain:

each foot costs 1 extra.

Physical distance:

10 feet

Movement cost:

20 feet

Remaining:

0

The character cannot move the final 5 feet using normal movement that turn.

COMPLETE CREATURE-SPACE EXAMPLE

You are:

MEDIUM

A Huge hostile creature blocks the corridor.

Because Huge is two Sizes larger than Medium:

YOU MAY PASS THROUGH ITS SPACE

But because it is:

  • not Tiny

  • not your ally

its space is:

DIFFICULT TERRAIN

You must pay the increased movement cost.

You also cannot willingly end your move inside its space.

COMPLETE ALLY EXAMPLE

Your ally occupies the square immediately in front of you.

You can move through their space because:

THEY ARE YOUR ALLY

Their space isn't Difficult Terrain for you under the creature-space rule.

But you still can't willingly finish your move sharing that space.

COMPLETE PRONE EXAMPLE

Speed:

30 feet

You begin your turn Prone.

To stand:

SPEND 15 FEET OF MOVEMENT

Remaining:

15 FEET

You can then move up to 15 additional feet normally, subject to terrain and other movement rules.

MOVEMENT DECISION FLOW

When moving during combat, ask:

STEP 1 — WHAT IS MY SPEED?

Example:

30 feet

STEP 2 — HOW MUCH HAVE I ALREADY MOVED?

Subtract it from your available movement.

STEP 3 — WHAT KIND OF TERRAIN AM I ENTERING?

Normal?

Difficult Terrain?

Something with a special rule?

STEP 4 — AM I USING A SPECIAL MOVEMENT MODE?

Climbing?

Crawling?

Swimming?

Another type of movement?

Apply its movement costs.

STEP 5 — IS ANOTHER CREATURE IN THE SPACE?

If yes:

ask whether you are permitted to move through it.

STEP 6 — DOES THAT CREATURE'S SPACE COUNT AS DIFFICULT TERRAIN?

Unless it is:

  • Tiny

  • your ally

the creature's space is Difficult Terrain for you under this rule.

STEP 7 — CAN I FINISH THERE?

Normally:

NO

You can't willingly end your move in another creature's occupied space.

COMMON BEGINNER MISTAKES

MISTAKE 1 — THINKING YOU MUST MOVE YOUR FULL SPEED

You can move:

UP TO YOUR SPEED

including zero movement.

MISTAKE 2 — THINKING MOVEMENT MUST HAPPEN ALL AT ONCE

You can split it around Actions, Bonus Actions, and Reactions taken during your turn.

MISTAKE 3 — THINKING DIFFICULT TERRAIN HALVES YOUR SPEED DIRECTLY

The rule instead says:

EACH FOOT COSTS 1 EXTRA FOOT

 

That distinction matters when only part of your movement passes through Difficult Terrain.

MISTAKE 4 — STACKING MULTIPLE SOURCES OF DIFFICULT TERRAIN

Difficult Terrain isn't cumulative.

A space either is Difficult Terrain or isn't.

MISTAKE 5 — USING AN ACTION TO DROP PRONE

Voluntarily dropping Prone uses:

NO ACTION

and:

NO SPEED

provided your Speed isn't 0.

MISTAKE 6 — STANDING FROM PRONE FOR FREE

Standing costs movement equal to:

HALF YOUR SPEED, ROUNDED DOWN

 

MISTAKE 7 — THINKING A LARGE CREATURE OCCUPIES ONE SQUARE

Large:

2 × 2 SQUARES

Huge:

3 × 3

Gargantuan:

4 × 4

 

MISTAKE 8 — THINKING YOU CAN MOVE THROUGH EVERY ENEMY

You need a rule permitting it.

The standard permissions include:

  • ally

  • Incapacitated creature

  • Tiny creature

  • creature two Sizes larger or smaller

 

MISTAKE 9 — THINKING PASSING THROUGH MEANS YOU CAN STOP THERE

You cannot normally willingly end your move in another creature's space.

MISTAKE 10 — FORGETTING CREATURE SPACES CAN BE DIFFICULT TERRAIN

Another creature's space is Difficult Terrain unless that creature is:

TINY

or:

YOUR ALLY

 

LESSON 19 — KEY TAKEAWAYS

MOVEMENT

On your turn:

MOVE UP TO YOUR SPEED

or move less, including not moving at all.

BREAKING UP MOVEMENT

You can divide your movement around Actions, Bonus Actions, and Reactions taken during your turn.

DIFFICULT TERRAIN

1 FOOT OF PHYSICAL MOVEMENT COSTS 2 FEET OF MOVEMENT

and multiple causes of Difficult Terrain do not stack.

DROP PRONE

Costs:

NO ACTION

NO MOVEMENT

but you can't voluntarily do it if Speed is 0.

STAND FROM PRONE

Costs:

HALF YOUR SPEED, ROUNDED DOWN

 

CREATURE SIZES

Tiny

Small

Medium

Large

Huge

Gargantuan

Size determines how much map space a creature occupies.

YOU CAN PASS THROUGH

  • an ally

  • an Incapacitated creature

  • a Tiny creature

  • a creature two Sizes larger or smaller than you

 

CREATURE SPACES

Another creature's space is Difficult Terrain unless the creature is:

TINY

or:

YOUR ALLY

 

YOU CAN'T NORMALLY END MOVEMENT IN ANOTHER CREATURE'S SPACE

And if you somehow end a turn there, you become Prone unless you are Tiny or larger than the other creature.

NEXT LESSON

LESSON 20 — MAKING AN ATTACK: TARGETS, MODIFIERS, AND ATTACK RESOLUTION

You now know:

when your turn happens

and:

where you can move.

Next comes the central offensive mechanic of combat:

MAKING AN ATTACK

In Lesson 20, we will study:

  • how attacks are initiated

  • choosing a target

  • what can make an attack possible or impossible

  • Attack Rolls in combat

  • relevant Ability Modifiers

  • Proficiency

  • Advantage and Disadvantage in attack situations

  • resolving a hit or miss

  • attacks granted by Actions, Bonus Actions, and Reactions

  • unseen attackers and unseen targets where relevant

  • how an attack proceeds from declaration to final result

This will build directly on the Attack Roll fundamentals from Lesson 7 and place them inside the full combat sequence.

SRD 5.2.1 ATTRIBUTION

This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.