Giant Rat 5e: Pack Tactics, Numbers and Running a Rat Horde

A giant rat is a CR 1/8 Small beast with AC 12, 7 hit points, darkvision and one attack: a +4 bite for 4 damage. One rat is a nuisance. Six rats are a real fight at level 1, because of Pack Tactics: a rat attacks with Advantage whenever another rat is next to its target. The 2024 rules make every rat a little better (AC 13, +5 to hit for 5 damage, a 30-foot climb speed and a +5 Dexterity save) and drop the 2014 diseased variant.

Table of Contents

• •Giant Rat Stat Block (2014)
• •The Diseased Giant Rat (2014 Variant)
• •Giant Rat in the 2024 Rules
• •How Giant Rats Fight
• •How Many Giant Rats for a Level 1 Party?
• •Running a Big Pack Without Slowing the Game
• •How Players Beat Giant Rats
• •Giant Rat Encounter Ideas
• •Frequently Asked Questions

Giant Rat Stat Block (2014)

The standard giant rat from SRD 5.1.

Everything about this stat block is small except one trait. AC 12 means a level 1 fighter with +5 to hit lands 70% of attacks. 7 hit points means one hit from almost anything kills it. Its bite (+4, 1d4 + 2) is weaker than a goblin's scimitar.

Pack Tactics is the reason the giant rat shows up in so many first dungeons. Advantage takes the rat's chance to hit AC 16 from 45% to about 70%, a jump of more than half. A few rats around one character get a lot of hits in.

Keen Smell gives Advantage on Perception checks that rely on smell. With darkvision 60 feet, a rat pack in a dark cellar knows where the party is long before the party sees it.

The Diseased Giant Rat (2014 Variant)

SRD 5.1 includes a variant giant rat that carries disease. It has the same statistics and CR (1/8, 25 XP), and its bite does the same 4 (1d4 + 2) piercing damage.

The difference is the disease. A creature bitten by a diseased rat makes a DC 10 Constitution save. On a failure it contracts a disease that:

• •prevents it from regaining hit points by anything except magic, and
• •reduces its hit point maximum by 3 (1d6) every 24 hours,
• •and kills it if its hit point maximum reaches 0.

A DC 10 save is easy: a character with +2 Constitution fails only on a 7 or lower, 35% of the time. But one failure out of six bites is likely, and the effect is slow and nasty. It turns a dungeon crawl into a race. Short rests stop working for the infected character (spending Hit Dice is not magical healing), and each day of travel cuts their maximum.

Cures in the 2014 rules: Lesser Restoration ends one disease, and a paladin's Lay on Hands can cure a disease for 5 points from its pool. Make sure the party has access to one or the other before you use diseased rats on a level 1 group far from a temple.

The 2024 rules don't include a diseased giant rat, and 2024 Lesser Restoration only ends conditions, not diseases. If you're running 2024 rules and want the disease, use the 2014 variant as written and decide in advance what cures it.

Giant Rat in the 2024 Rules

SRD 5.2.1 keeps the giant rat at CR 1/8 with 7 hit points and Pack Tactics, and improves it nearly everywhere else.

The climb speed is the change that plays the biggest part. 2024 rats can run up walls, along rafters and across ceilings at full speed. That lets them reach a character from a direction the party isn't guarding, and it lets them escape a fight by going somewhere the party can't follow. The +5 Dexterity save also makes Dexterity-based area spells less reliable against them.

How Giant Rats Fight

The Pack Tactics math. Pack Tactics needs one other rat within 5 feet of the target, and that rat can't be incapacitated. The table ignores critical hits.

A Medium character standing in the open has eight spaces around it. Eight 2024 rats in those spaces deal about 30 damage a round to an AC 16 character. That's two and a half times a level 1 fighter's hit points. Against a wizard with mage armor (AC 13), four 2024 rats deal about 17 a round, roughly twice a level 1 wizard's hit points.

Arrive in pairs. The first rat to reach a character has no ally next to the target and attacks without Advantage. Move rats as pairs or groups so that each one arrives next to a friend.

Surround the weakest target. Rats are animals, but animals hunt the slow and the small. Pick the character with the lowest AC, or whoever is standing apart from the group, and pile on.

Use the walls (2024). With a climb speed, a rat can come down a wall or drop from a rafter into a space next to a character on the second rank. Characters who think the fighter is protecting them aren't safe.

Fight in the dark. All giant rats have darkvision 60 feet. In a sewer or cellar, the party's light source shows the rats exactly where the party is, while rats beyond the light are harder to see.

Run when it goes badly. Hungry animals flee when they're losing. When half the pack is dead, have the rest scatter into holes and drains. A rat that escapes can come back later with more rats.

How Many Giant Rats for a Level 1 Party?

The SRD 5.2.1 rules use giant rats in their own encounter-building example: a Low-difficulty encounter for four level 1 characters has a 200 XP budget, and 6 giant rats (150 XP) fit inside it. Here's the full range under 2024 rules:

The 2014 Dungeon Master's Guide method disagrees strongly, because its group multiplier punishes numbers. Four rats are 100 XP, doubled to 200, which is a Medium fight for four level 1 characters. Six rats (150 XP, doubled to 300) are Hard. Eight rats (200 XP, multiplied by 2.5 to 500) are past Deadly. Run your party's numbers in the encounter calculator.

Which is right? It depends on the terrain. Eight rats in an open room where they can surround someone are very dangerous. Eight rats coming down a 5-foot corridor one at a time are an easy fight. Some guidance:

• •Level 1: 4 to 6 rats in a room where they can surround. More than 8 is a risk to a level 1 character's life.
• •Level 2 to 3: rats stop being a threat on their own. Use them alongside a leader: a wererat, a swarm of rats or two, or a cultist who keeps them.
• •Level 4+: rats are scenery, a sign of what lives deeper in the sewer.

Giant rat vs swarm of rats vs rat

Two giant rats cost the same 50 XP as a swarm. The rats deal more damage (two attacks with Advantage), and the swarm takes much longer to kill with weapons. Use giant rats when you want the party to feel surrounded. Use a swarm when you want them to feel that their swords aren't working.

Running a Big Pack Without Slowing the Game

Twelve rats can turn a 20-minute fight into an hour. Ways to keep it moving:

• •One initiative for the pack. Roll once for all the rats, or once per group of four.
• •Roll attacks in a batch. For four rats attacking with Advantage, roll eight d20s in pairs and keep the higher of each pair. Our dice roller handles the damage.
• •Use fixed damage. 4 per hit (2014) or 5 (2024). You lose nothing by not rolling 1d4.
• •Group the tokens. Move rats in packs of three or four and treat each pack as a unit for movement decisions.
• •Skip the hit point tracking. Any hit of 7 or more kills a rat, and most weapon hits from level 1 characters reach that. Track damage only on the rats that survive a hit.

An initiative tracker helps once rats, a wererat and the party are all in the same fight.

How Players Beat Giant Rats

Find a doorway. In a 5-foot corridor or doorway, only one or two rats can reach you at a time, and Pack Tactics needs a second rat next to you. Characters with their backs to a wall cut the number of attackers from eight to five.

Kill the second rat first. A rat on its own doesn't have Advantage. Thinning a group so that no two rats share a target removes the trait.

Area spells. At 7 hit points, rats die to most 1st-level area spells.

• •Thunderwave: 2d8 thunder on a failed Constitution save. Rats have Constitution +0, so against DC 13 they fail 60% of the time, and 2d8 rolls 7 or more about 77% of the time.
• •Burning Hands: 3d6 fire, which kills on a failed save over 90% of the time. But it's a Dexterity save, and 2024 rats have +5, so against DC 13 they fail only 35% of the time (50% for 2014 rats). Thunderwave is better against 2024 rats.

Light the room. Darkvision only helps where it's dark. Bright light across the whole room removes the rats' edge and shows the party every direction they're coming from.

Don't get bitten by diseased ones. If you suspect disease (rats in a plague town, rats eating corpses), have a paladin or someone with Lesser Restoration ready, and treat every bite as a potential problem.

Using one yourself. A level 2 druid can Wild Shape into a giant rat in both editions (it's CR 1/8 with no fly or swim speed). The 2024 rat's climb speed makes it a decent scouting form for crawling through vents and up walls.

Giant Rat Encounter Ideas

The granary. A town's grain store is losing a sack a night. Eight giant rats live in the rafters and under the floor (2024 rats move between them freely with their climb speed). The twist: the miller has been feeding them on purpose to cover up how much grain he's been selling on the side.

The flooded cellar. The party drops into a cellar where the floor is under a foot of water. It's difficult terrain for everyone, rats included. Six rats come from three drain pipes, two at a time, and the party has to block the pipes or fight forever.

The rat-catcher's ledger. A rat-catcher says he has cleared the city's sewers four times this year, but the rats keep coming back. He's paying the party to find out why. In the deepest tunnel, the giant rats are led by a wererat, who has been paying the rat-catcher to report the sewers clear.

Loreify's session notes can track ongoing threats like a disease that hasn't been cured yet, so nobody forgets that the rogue's hit point maximum dropped again.

Frequently Asked Questions

What CR is a giant rat in 5e?

A giant rat is CR 1/8, worth 25 XP, in both the 2014 and 2024 rules. It has 7 hit points and AC 12 (2014) or AC 13 (2024).

How does Pack Tactics work?

A giant rat has Advantage on an attack roll against a creature if at least one of its allies is within 5 feet of that creature and the ally isn't incapacitated. In practice, every rat after the first one to reach a character attacks with Advantage.

What does a diseased giant rat do?

It's a 2014 variant whose bite forces a DC 10 Constitution save. On a failure, the target can't regain hit points except by magic, and its hit point maximum drops by 1d6 every 24 hours until the disease is cured. If the maximum reaches 0, it dies.

How many giant rats should I use for a level 1 party?

For four level 1 characters, 4 to 6 rats is a solid fight. Under 2024 rules, 6 to 8 rats fits a Low encounter and 12 a Moderate one; under the 2014 guidelines, 6 rats is already Hard because of the group multiplier.

Can giant rats climb in 5e?

Only in the 2024 rules, which give them a 30-foot climb speed. The 2014 giant rat has a 30-foot walking speed and nothing else.

Stat blocks: System Reference Document 5.1 (2014) and 5.2.1 (2024), Wizards of the Coast, CC-BY-4.0. Tactics, encounter math and ideas are Loreify's own.