Why Does My IP Address Keep Changing?

The real reasons your public IP address changes — dynamic DHCP leases, reboots, CGNAT and more — and how to get a stable address if you actually need one.

If you have noticed your IP address keeps changing, nothing is broken — for most home connections that is exactly how the internet is designed to work. Your internet provider hands you a dynamic public address that it can reclaim and reassign over time, so the number you saw last week may not be the one you have today. This guide explains every reason an address changes, whether it matters for you, and the concrete ways to get a stable address if you need one.

Public IP vs private IP: which one is changing?

First, a quick but important distinction, because "my IP changed" can mean two very different things:

• Your public IP is the single address the whole internet sees, assigned by your ISP. This is the one people usually mean, and it can change on its own.
• Your private IP is the internal address your router gives each device (like 192.168.1.24) via DHCP. It can also change when a device reconnects.

The two are linked by NAT but change for different reasons. Want to check your current public address right now? IP Animals shows it instantly, and our guide to finding your IP covers the private one.

Why your public IP address changes

Home connections almost always use dynamic addressing, and several everyday events can trigger a new one:

1. Your DHCP lease expired or renewed

Your ISP does not give you an address forever. It grants a lease for a set period, and when that lease renews, you might receive the same address or a different one. This can happen quietly in the background without you doing anything at all.

2. You rebooted or unplugged your router

Powering the router off, even briefly, often causes it to request a fresh address when it comes back. Leaving it unplugged for a while makes a new address more likely, because the old lease is more likely to be released and reassigned to someone else in the meantime.

3. Your ISP renumbered or rotated addresses

Providers periodically reorganise their networks, and some deliberately rotate customer addresses on a schedule for operational or privacy reasons. When that happens, your address changes with no action on your side.

4. You switched networks or connection type

Moving between Wi-Fi and mobile data, connecting through a different router, or using a VPN all change the public address the internet sees, because your traffic is now leaving through a different door entirely.

5. You're behind CGNAT

Many providers, especially mobile and newer fibre networks, use carrier-grade NAT (CGNAT) to share one public IP among many customers. Your connection is given a shared-address-space WAN address (in the 100.64.0.0/10 range) rather than a unique public one, and how you appear to the internet can shift as the ISP manages that pool.

Why your private (local) IP changes

Inside your home, your router's DHCP server leases addresses to your devices too. A device can end up with a different local IP when it reconnects after being off for a while, when the router reboots, or when the DHCP pool reshuffles. That is usually harmless — until you have a printer, server or port-forwarding rule that expects a device to stay put. The fix there is a static local IP or DHCP reservation, which pins the device to one address.

Does a changing IP address actually matter?

For everyday browsing, streaming and gaming: no, not at all. Dynamic addressing is invisible and even offers a small privacy benefit, since you are not permanently tied to one number. It only becomes a nuisance in specific situations:

How to get a stable IP address

If a changing address is causing you real problems, you have three practical options, from easiest to most involved.

Option 1: Use dynamic DNS (easiest)

Dynamic DNS (DDNS) is the most popular fix and solves the majority of cases. Instead of chasing the number, you get a fixed hostname (like myhome.example-ddns.net) that a small client keeps pointed at your current IP automatically. Many routers have a DDNS client built in — look under Dynamic DNS in the admin page — so whenever your IP changes, the hostname updates within minutes and your bookmarks keep working. This does not work well behind CGNAT, though, because there is no reachable public address to point at.

Option 2: Reduce unnecessary changes

You cannot force a dynamic IP to freeze, but you can avoid triggering changes: keep your router powered on rather than unplugging it overnight, and avoid manually releasing your lease. In practice, many ISPs will keep handing you the same address for long stretches as long as your connection stays up.

Option 3: Ask your ISP for a static IP

The definitive fix is a genuine static public IP from your provider. This is usually a paid add-on and often only offered on business plans, but it gives you one address that never changes — ideal for mail servers or strict allowlists. If you are on CGNAT, requesting a static or at least a dedicated public IP is also the only way to enable reliable inbound connections and port forwarding.

The short version

Your IP changing is normal, expected behaviour driven by DHCP leases, reboots, ISP housekeeping and CGNAT. It matters only if you host services or rely on a fixed address, and when it does, dynamic DNS handles most situations, with a paid static IP from your ISP as the guaranteed answer. Either way, whenever you want to know your address at this exact moment, a quick check on IP Animals tells you in a heartbeat.