Docker Image Size Analyzer
Paste your Dockerfile to get a layer-by-layer size estimate, optimization opportunities, and a suggested multi-stage build.
Layer Analysis
Paste a Dockerfile and click Analyze.
Base Image Size Comparison
| Base Image | Compressed Size | Notes |
|---|---|---|
| scratch | 0 MB | Only for static binaries (Go/Rust) |
| gcr.io/distroless/base | ~2 MB | No shell, minimal attack surface |
| alpine:3 | ~5 MB | musl libc, may break native modules |
| debian:bookworm-slim | ~30 MB | Good compatibility, glibc |
| node:20-alpine | ~45 MB | Node on Alpine |
| node:20-slim | ~80 MB | Node on Debian slim |
| python:3.12-slim | ~70 MB | Python on Debian slim |
| node:20 | ~350 MB | Full Debian, avoid in production |
| ubuntu:22.04 | ~30 MB | Great compatibility but bulky |
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See what's included → Browse all deals →Frequently Asked Questions
Why should I care about Docker image size?▼
Smaller images pull faster in CI/CD pipelines (critical for autoscaling), start containers faster in serverless/ephemeral environments, consume less storage in registries (reducing costs), and have a smaller attack surface — fewer packages mean fewer CVEs to patch. A 200 MB image pulls ~5× faster than a 1 GB image on a 100 Mbps connection.
What is a multi-stage build and when should I use it?▼
Multi-stage builds use multiple FROM statements. Stage 1: install build tools, compile your app. Stage 2 (final): copy only the compiled output into a minimal base image — no build tools, no source code. Use multi-stage builds whenever you have a compile step: Go, Rust, Java/Gradle, TypeScript, webpack bundles. The savings can be enormous: a Go app might go from 800 MB (golang:latest) to 15 MB (scratch).
What base image should I use?▼
scratch: zero-overhead, only for statically compiled binaries (Go, Rust). alpine: ~5 MB, uses musl libc — small but may have glibc compatibility issues. debian:slim / ubuntu:22.04-minimal: 50–80 MB, good compatibility. node:alpine vs node:slim: alpine is ~50 MB smaller but has native module compilation issues. For production, prefer distroless (gcr.io/distroless) for security without the shell.
How do I minimize apt-get layer size?▼
Always combine update, install, and clean in ONE RUN command: RUN apt-get update && apt-get install -y --no-install-recommends pkg1 pkg2 && rm -rf /var/lib/apt/lists/*. Split commands create separate layers where package lists remain in the image. The --no-install-recommends flag skips optional packages, often saving 50–200 MB.
What should be in .dockerignore?▼
Always include: node_modules/ (can be 500 MB+), .git/, *.log, .env, dist/, build/, coverage/, .DS_Store, *.test.ts, __tests__/. Not having a .dockerignore means COPY . . sends everything to the build context, which is slow and may include secrets.