diff --git a/.env b/.env
index 40f9d76..7e47048 100644
--- a/.env
+++ b/.env
@@ -26,6 +26,7 @@ SMTP_PORT=587
 
 # Postgres
 POSTGRES_SERVER=localhost
+POSTGRES_PORT=5432
 POSTGRES_DB=app
 POSTGRES_USER=postgres
 POSTGRES_PASSWORD=changethis
diff --git a/backend/app/alembic/env.py b/backend/app/alembic/env.py
index c146cf6..926f119 100755
--- a/backend/app/alembic/env.py
+++ b/backend/app/alembic/env.py
@@ -32,8 +32,9 @@ def get_url():
     user = os.getenv("POSTGRES_USER", "postgres")
     password = os.getenv("POSTGRES_PASSWORD", "")
     server = os.getenv("POSTGRES_SERVER", "db")
+    port = os.getenv("POSTGRES_PORT", "5432")
     db = os.getenv("POSTGRES_DB", "app")
-    return f"postgresql+psycopg://{user}:{password}@{server}/{db}"
+    return f"postgresql+psycopg://{user}:{password}@{server}:{port}/{db}"
 
 
 def run_migrations_offline():
diff --git a/backend/app/core/config.py b/backend/app/core/config.py
index 060090f..56d09ee 100644
--- a/backend/app/core/config.py
+++ b/backend/app/core/config.py
@@ -48,6 +48,7 @@ class Settings(BaseSettings):
     PROJECT_NAME: str
     SENTRY_DSN: HttpUrl | None = None
     POSTGRES_SERVER: str
+    POSTGRES_PORT: int = 5432
     POSTGRES_USER: str
     POSTGRES_PASSWORD: str
     POSTGRES_DB: str = ""
@@ -60,6 +61,7 @@ class Settings(BaseSettings):
             username=self.POSTGRES_USER,
             password=self.POSTGRES_PASSWORD,
             host=self.POSTGRES_SERVER,
+            port=self.POSTGRES_PORT,
             path=self.POSTGRES_DB,
         )
 
diff --git a/deployment.md b/deployment.md
index b170a73..4ea39eb 100644
--- a/deployment.md
+++ b/deployment.md
@@ -137,6 +137,7 @@ You can set several variables, like:
 * `SMTP_PASSWORD`: The SMTP server password to send emails.
 * `EMAILS_FROM_EMAIL`: The email account to send emails from.
 * `POSTGRES_SERVER`: The hostname of the PostgreSQL server. You can leave the default of `db`, provided by the same Docker Compose. You normally wouldn't need to change this unless you are using a third-party provider.
+* `POSTGRES_PORT`: The port of the PostgreSQL server. You can leave the default. You normally wouldn't need to change this unless you are using a third-party provider.
 * `POSTGRES_PASSWORD`: The Postgres password.
 * `POSTGRES_USER`: The Postgres user, you can leave the default.
 * `POSTGRES_DB`: The database name to use for this application. You can leave the default of `app`.
diff --git a/docker-compose.yml b/docker-compose.yml
index 50818fc..fe3eab3 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -100,6 +100,7 @@ services:
       - SMTP_PASSWORD=${SMTP_PASSWORD}
       - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
       - POSTGRES_SERVER=db
+      - POSTGRES_PORT=${POSTGRES_PORT}
       - POSTGRES_DB=${POSTGRES_DB}
       - POSTGRES_USER=${POSTGRES_USER?Variable not set}
       - POSTGRES_PASSWORD=${POSTGRES_PASSWORD?Variable not set}