How to Install PostgreSQL & Use psql: Beginner Guide

If you searched for how to install PostgreSQL and use psql, here is the short answer: download the PostgreSQL installer for your operating system, run it and set a password, then open the psql command-line tool that comes with it to type commands and run SQL. This guide walks through every step for Windows, Mac, and Linux, then teaches you the handful of psql commands you actually need as a beginner.

You do not need any prior database experience to follow along. By the end, you will have PostgreSQL running on your machine and you will know how to create a database, create a table, and run your first query in psql.

What Are PostgreSQL and psql?

PostgreSQL (often just called "Postgres") is a free, open source RDBMS. RDBMS stands for Relational Database Management System — it is software that stores data in tables made of rows and columns, and lets you search, sort, and connect that data using SQL (Structured Query Language).

psql is the command-line client that comes bundled with PostgreSQL. It is a small text-based program you type commands into. You use psql to connect to a PostgreSQL server, look at your databases and tables, and run SQL statements. Think of PostgreSQL as the engine and psql as one of the steering wheels you can use to drive it.

Step 1: Install PostgreSQL on Your Computer

PostgreSQL is free to download from the official site at postgresql.org/download. The installer sets up three things at once: the PostgreSQL server (the database itself), pgAdmin (an optional graphical tool), and psql (the command-line tool this guide focuses on).

Installing on Windows

1. Go to postgresql.org/download/windows and download the installer (it is made by a company called EDB).
2. Run the downloaded file and click through the setup wizard.
3. When asked, set a password for the default superuser account, named postgres. Write this password down — you will need it in a moment.
4. Keep the default port, 5432, unless something else on your computer is already using it.
5. Finish the install. psql is now available from the Start Menu as "SQL Shell (psql)", or from any terminal.

Installing on Mac

brew install postgresql@16
brew services start postgresql@16

The first line uses Homebrew (a package manager for Mac) to download and install PostgreSQL version 16. The second line starts the PostgreSQL server as a background service, so it keeps running even after you close the terminal. If you don't have Homebrew yet, install it first from brew.sh.

Installing on Linux (Ubuntu or Debian)

sudo apt update
sudo apt install postgresql postgresql-contrib

The first line refreshes your system's list of available software. The second line installs PostgreSQL along with a few extra useful tools (postgresql-contrib). On most Linux systems, the server starts automatically right after installation.

Step 2: Open psql for the First Time

psql -U postgres

This command opens psql and connects as the postgres user. The -U flag means "user". You may be asked for the password you set during installation. Once it works, your prompt changes to something like postgres=#, which means psql is ready and waiting for a command.

On Windows, if you get a message saying psql is not recognized, use the "SQL Shell (psql)" app from the Start Menu instead — it opens psql with the right settings already filled in.

Step 3: Learn the Most Useful psql Commands

psql has two kinds of input. Backslash commands (like \l) are shortcuts built into psql itself and do not end with a semicolon. SQL statements (like SELECT) are sent to the database and must end with a semicolon (;). Here are the backslash commands worth memorizing first:

Step 4: Run Your First SQL Query

CREATE DATABASE practice;
\c practice
CREATE TABLE greetings (id SERIAL PRIMARY KEY, message TEXT);
INSERT INTO greetings (message) VALUES ('Hello, PostgreSQL!');
SELECT * FROM greetings;

Line by line: CREATE DATABASE practice; makes a new, empty database called practice. \c practice switches psql into that database. CREATE TABLE greetings (...) makes a table with an auto-incrementing id column (SERIAL means PostgreSQL fills it in for you) and a message column that holds text. INSERT INTO ... VALUES (...) adds one row of data. Finally, SELECT * FROM greetings; asks PostgreSQL to show every column (*) for every row in the greetings table — you should see your greeting printed back to you.

Common Beginner Problems (and Fixes)

• "psql: FATAL: password authentication failed" — you typed the wrong password for the postgres user, or none was set; reinstall or reset the password with the pgAdmin tool if unsure.
• "psql: command not found" — psql is not on your system PATH; on Mac, run brew link postgresql@16, or on Windows use the "SQL Shell (psql)" shortcut instead.
• "could not connect to server: Connection refused" — the PostgreSQL service is not running; on Mac run brew services start postgresql@16, on Linux run sudo systemctl start postgresql.
• Forgot to add a semicolon — psql will just sit there waiting on a new line; type ; and press Enter to finish the command.

What to Learn Next

Now that PostgreSQL is installed and you can run commands in psql, the natural next step is learning how to design and create your own tables properly, including choosing the right data types and keys.

Installing PostgreSQL and getting comfortable in psql is the foundation for everything else you'll do with databases — from writing your first SELECT statement to designing multi-table applications. Take it slowly, practice the commands above a few times, and they will quickly become second nature.