Quick Answer

# Remove everything unused (images, containers, networks)
docker system prune -a

# Remove unused images only
docker image prune -a

# Remove a specific image
docker rmi IMAGE_ID

Run docker system df first to see what’s actually taking up space.

Check Disk Usage First

docker system df

Sample output:

TYPE            TOTAL     ACTIVE    SIZE      RECLAIMABLE
Images          23        5         8.2GB     6.1GB (74%)
Containers      12        3         142MB     98MB (69%)
Local Volumes   8         4         2.3GB     1.1GB (47%)
Build Cache     0         0         0B        0B

The RECLAIMABLE column shows how much space you can recover.

Remove All Unused Docker Resources at Once

# Remove stopped containers, unused images, unused networks
docker system prune

# Also remove unused volumes (WARNING: deletes data)
docker system prune --volumes

# Skip the confirmation prompt
docker system prune -a -f

docker system prune -a removes all images not used by a running container — not just dangling ones.

Remove Docker Images

# Remove dangling images only (<none>:<none>)
docker image prune

# Remove ALL unused images
docker image prune -a

# Remove a specific image by ID or name
docker rmi nginx:1.25
docker rmi IMAGE_ID

# Force remove (even if tagged or referenced)
docker rmi -f IMAGE_ID

Repeated builds without tagging produce <none> images that accumulate silently. These are usually the biggest disk hogs.

Remove Images Older Than a Specific Time

# Remove images unused for more than 24 hours
docker image prune -a --filter "until=24h"

# Remove images unused for more than 7 days
docker image prune -a --filter "until=168h"

Remove Docker Containers

# Remove all stopped containers
docker container prune

# Remove a specific container
docker rm CONTAINER_ID

# Force remove a running container
docker rm -f CONTAINER_ID

# List stopped containers before removing
docker ps -a --filter status=exited

# Remove all stopped containers at once
docker rm $(docker ps -a -q --filter status=exited)

Remove Docker Volumes

# Remove all unused volumes
docker volume prune

# List volumes first
docker volume ls

# Remove a specific volume by name
docker volume rm VOLUME_NAME

Be careful: unused volumes that contain database data will be permanently deleted.

Remove Build Cache

Build cache accumulates on CI/CD systems and can reach several GB.

# Remove all build cache
docker builder prune -f

# Remove only cache older than 48 hours
docker builder prune --filter "until=48h"

Automate Cleanup with Cron

# Edit crontab
crontab -e

# Run docker image prune every Sunday at 2am
0 2 * * 0 docker image prune -af >> /var/log/docker-cleanup.log 2>&1

Common Pitfalls

  • docker system prune skips images used by running containers, but removes images used by stopped containers
  • docker system prune --volumes before docker-compose down can delete volumes still referenced by compose
  • docker image prune -a means Docker must re-pull all images on next run — avoid on production
  • --volumes removes database data — only use on dev environments

FAQ

Q: What is the docker command to remove unused images? docker image prune -a removes all unused images. Without -a, only dangling (<none>) images are removed.

Q: How do I remove all Docker images at once? docker rmi $(docker images -q). This fails for images used by running containers — add -f to force.

Q: What is the difference between docker image prune and docker image prune -a? Without -a, only dangling (untagged <none>) images are removed. With -a, all images not used by a running container are removed.

Q: How do I remove a Docker image by name? docker rmi IMAGE_NAME:TAG, for example docker rmi nginx:1.24.

Q: Does docker system prune delete volumes? Not by default. Add the --volumes flag explicitly: docker system prune --volumes.

Q: How do I see what Docker is using for disk space? docker system df for a summary. docker system df -v for per-image/container detail.

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