How to Check Internet Speed at an Address Before You Buy

The listing says "fast broadband available", you buy the house, and the first video call from your new home office freezes every two minutes. Agents rarely know the real connection at a property, so the only way to be sure is to check internet speed at an address yourself before you make an offer. It takes about 30 minutes and a phone, and it can save you years of slow uploads or a 3,000 dollar bill for a new line.

I approach this the way I approach any property data: start with the official records, then test on site, then compare the two. Here is the process.

Why the listing and the agent cannot tell you

Phrases like "fibre area" or "NBN ready" describe the street or the suburb, not the actual connection to the house. Two homes on the same block can have very different service. One might have fibre to the premises, delivering 500 Mbps or more, while the neighbour is on an old copper line where 25 Mbps is a good day.

The reasons are boring but real: a property built before a rollout may never have been connected, a long private driveway can add distance to the node, and older apartment blocks often share one internal cable system. None of this shows up in listing photos.

Step one: check internet speed at an address online

Start with the address lookup on the national network operator's website. In Australia that is the NBN address check, in the UK Ofcom's broadband and mobile checker, in New Zealand the Chorus or Broadband Map lookup, and in the US the FCC National Broadband Map. Enter the exact street number, including unit number if it is an apartment.

Write down three things from the result:

• Connection technology: fibre to the premises, fibre to the curb, fibre to the node, cable, fixed wireless or satellite.
• Maximum plan speed available: often listed as tiers like 100, 250, 500 or 1000 Mbps.
• Status: whether the address is already connected or needs installation, and whether an upgrade is planned.

Upload speed is the number most buyers forget. If anyone in the house works from home, sends large files or streams, an upload of 1 to 5 Mbps will hurt much more than a modest download.

Step two: test the mobile signal on site

At the inspection, open a speed test app on your phone in three places: the room you would use as an office, the main living area and the back of the house. Run each test twice. Note download, upload and ping. Check all the bars for your carrier, then ask a friend on a different network to text you a screenshot if they can visit.

This matters for two reasons. Mobile data is your backup when the fixed line fails, and in some areas a 5G home modem is actually a better option than the fixed connection. If your phone shows 150 Mbps on 5G in the living room and the address check shows copper, that is useful bargaining knowledge.

Visit at different times if you can. A test at 11:00 on a weekday tells you little about 20:00 on a Sunday, when the whole street is streaming.

Step three: ask the right people

The current owner or tenant knows exactly what they get. At an open home, ask the agent directly: "What internet plan does the vendor have, and what speeds do they see?" Some vendors will happily show a recent bill. If they work from home, they will often volunteer whether calls drop.

Neighbours are just as useful. When you walk the street, a pattern I recommend in reading a neighbourhood before you make an offer, a friendly question over a fence about the internet takes 20 seconds and gives an honest answer.

Finally, look at the house itself. A fibre connection box on an outside wall or in the garage is a strong sign. A satellite dish on the roof of every second house tells you something too.

Where the "just upgrade it later" advice goes wrong

Many buyers are told not to worry about internet because "you can always upgrade". Sometimes that is true. Often it is not, and the cost is far higher than people assume.

If the address is on copper and no fibre upgrade is planned for the street, a private fibre build can cost anywhere from 2,000 to over 10,000 dollars, depending on distance and trenching. Many network operators only upgrade on a published schedule, and that schedule can move. Fixed wireless and satellite can fill the gap, but neither matches fibre for upload speed or reliability. For a buyer who works from home three days a week, a weak connection is a real cost, like a long commute, and it belongs in your offer calculation alongside other hidden factors such as neighbourhood noise.

It also affects resale. More buyers now check connection type before inspecting, and some filter listings by it. A house stuck on slow copper in a suburb where neighbours have fibre can sit longer on the market.

A quick checklist to take to the inspection

1. Run the national address lookup and save a screenshot of the result.
2. Run two mobile speed tests in three rooms.
3. Ask the agent for the vendor's current plan and speeds.
4. Look for a fibre box, cable outlet or roof dish.
5. Ask one neighbour about evening reliability.
6. If the result is poor, get an installation or upgrade quote before going unconditional.

Frequently asked questions

Can I check the internet speed of a house before buying it?

Yes. Use the national network operator's address checker to see the connection type and maximum speed, then run mobile speed tests during the inspection. Asking the current owner for their plan and real speeds fills in the rest.

What internet speed do I need to work from home?

For one person on video calls, a download of 50 Mbps and an upload of at least 10 Mbps is comfortable. Two people working at once, plus streaming, needs closer to 100 Mbps down and 20 Mbps up. Low latency matters as much as raw speed for calls.

Does fibre internet add value to a home?

It can make a home easier to sell, especially to buyers who work remotely, and a slow connection can lengthen days on market. Fibre rarely adds a fixed dollar amount, but a poor connection is a common reason for buyers to walk away or negotiate.