Your IP address changes based on your internet setup, not on a fixed schedule

Whether your IP address changes depends almost entirely on how your internet service provider (ISP) assigns it to you. If you have a dynamic IP address, your ISP can reassign it to you or someone else whenever your modem reconnects to the network — which might happen once a month, once a year, or somewhere in between. If you have a static IP address, it stays the same indefinitely until you or your ISP deliberately change it. Most home internet users have dynamic addresses and never notice the change because it happens in the background.

The timing is not random, but it is not predictable either. Your ISP controls when the lease on your dynamic IP expires. Some ISPs set that lease to 24 hours, others to 30 days, others to several months. Even if your lease is set to 30 days, you might get a new address after two weeks if your modem loses power or your connection drops. The address change itself takes seconds and requires no action from you.

Key Takeaways

  • Dynamic IP addresses (the standard for home internet) can change whenever your modem reconnects, but the timing depends on your ISP's lease settings, not a calendar.
  • Restarting your modem or losing internet connection can trigger an IP change even if your lease period has not expired.
  • Static IP addresses stay the same until you request a change, and most ISPs charge a monthly fee for this service.
  • You can check your current IP address by searching "what is my IP" in any browser, and you can see your ISP's lease expiration in your modem settings.

How dynamic IP leases work

When your modem connects to your ISP's network, the ISP assigns your modem an IP address and sets an expiration date on that assignment — the lease period. Common lease lengths are 24 hours, 7 days, or 30 days, though some ISPs use other intervals. Before the lease expires, your modem automatically requests a renewal from the ISP's DHCP server (the system that hands out addresses). If the ISP renews your lease, you keep the same address. If it does not renew, or if your modem cannot reach the DHCP server when the lease expires, your modem gets a new address the next time it connects.

The lease expiration is not the only trigger for an address change. If you restart your modem, unplug it, or lose internet connection for more than a few minutes, your modem will request a new address when it reconnects. Some ISPs reassign the old address right away; others hand out a different one. You have no way to predict which will happen without checking your IP address before and after the restart.

To see your current IP address, open any web browser and search for "what is my IP." Your ISP's modem or router may also display the address in its settings page, usually accessible by typing 192.168.1.1 or 192.168.0.1 into your browser's address bar (check your modem's label for the exact address). Some modems show the DHCP lease expiration date in those settings, which tells you roughly when your address might change next.

Why ISPs use dynamic addresses

ISPs use dynamic addresses because they have far fewer IP addresses available than they have customers. A typical ISP might have 10,000 addresses but 50,000 residential customers. By cycling addresses through customers — assigning an address only when someone is actively using it — the ISP can serve more people with the same pool of addresses. This system works because most home internet users do not need the same address all the time.

Dynamic addressing also makes it harder for someone outside your home to track your location or activity over long periods. If your address changes every month, a person trying to monitor your online behavior has to re-identify you each time. This is a side benefit, not the main reason ISPs use the system, but it does provide a small privacy advantage compared to a static address that never changes.

When you need a static IP address

Most home users never need a static IP address. Email, web browsing, streaming, and online gaming all work fine with a dynamic address. You only need a static address if you are running a service that other people connect to from outside your home — for example, a home security camera system that you want to access remotely, a personal web server, or a game server that friends join by typing in your IP address.

If you need a static address, contact your ISP and ask whether they offer one. Most large ISPs do, and they typically charge between $5 and $15 per month for the service. Some ISPs bundle static addresses with business-class internet plans. Once you have a static address, it remains the same until you cancel the service or request a change. You can also set up a dynamic DNS service (a free or low-cost third-party tool) that automatically updates a web address whenever your dynamic IP changes, which solves the problem without paying for a static address.

How to check if your address has changed

The simplest way to check your IP address is to search "what is my IP" in Google or another search engine. The search results will show your current address at the top of the page. If you want to track changes over time, write down your address or take a screenshot, then check again after a few days or weeks. If the numbers are different, your address has changed.

You can also check your IP address history through your modem's settings page. Log into your modem (usually by typing 192.168.1.1 into your browser) and look for a section labeled "DHCP," "IP Address," or "Network Status." Some modems display the current lease expiration date, which gives you a rough idea of when the next change might occur. If your modem does not show this information, your ISP's website or customer portal may have it, or you can call your ISP's support line and ask for your DHCP lease length.

What happens when your address changes

In most cases, you will not notice when your IP address changes. Websites you visit, email you send, and files you read all continue to work normally. Your internet speed, connection quality, and access to services remain the same. The only people who might notice are those trying to connect to a service running on your home network — for example, if you have a security camera and someone tries to access it using your old IP address, that connection will fail until they update it to your new address.

If you have set up port forwarding on your modem (a technical configuration that directs incoming connections to a specific device on your home network), a change in your external IP address does not affect port forwarding itself. However, if you have told someone to connect to your home network using your IP address, they will need the new address. This is why a dynamic DNS service or a static IP address is useful for services you want to access remotely.

Frequently Asked Questions

Can I keep my IP address from changing?

You can request a static IP address from your ISP, which stays the same indefinitely. Most ISPs charge $5 to $15 per month for this service. Alternatively, you can use a dynamic DNS service (often free) that gives you a web address that automatically updates whenever your IP changes, so you do not have to remember the numbers.

Does restarting my modem always change my IP address?

Restarting your modem does not always change your IP address, but it can. When your modem reconnects, it asks your ISP for an address. The ISP might give you the same one you had before, or it might assign a new one. There is no way to predict which will happen without checking your address before and after the restart.

Why did my IP address change multiple times in one day?

If your address changed several times in a single day, your internet connection probably dropped and reconnected multiple times. This can happen due to modem issues, router problems, or ISP network instability. Each time your modem reconnects, it requests a new address from your ISP. If this keeps happening, restart your modem and router, check that all cables are find, and contact your ISP if the problem continues.

Does my IP address change when I use a VPN?

Your actual IP address does not change when you use a VPN. However, websites you visit will see the VPN provider's IP address instead of yours. When you disconnect from the VPN, websites see your real IP address again. Your ISP can still see your real address because the VPN connection runs through your ISP's network.

How do I find out my ISP's DHCP lease length?

Check your modem's settings page (usually 192.168.1.1 in your browser) for a section labeled "DHCP" or "Network Status" that shows lease expiration. You can also call your ISP's support line and ask for your DHCP lease length, or check your ISP's website or customer portal. Knowing this number helps you predict roughly when your address might change next.