WiFi Heatmapper
Free WiFi heatmap tool. Visualize the weak points of your signal.
Walk through any space, drop measurement points as you go, and watch a live heatmap reveal where your Wi-Fi weakens.
- The core app is freeMap your space and export heatmaps without paying.
- No loginNo account or sign-up, just open it and start.
- Your data stays in your browserFloor plans and readings are never uploaded or sent anywhere.
How it works
- 1
Add a floor plan
Upload a picture of it, or sketch the walls in the app.
- 2
Measure where you stand
Click your spot and type the signal from your Wi‑Fi menu.
- 3
Read the map
Green is strong, red is weak. Export it as a PNG.
Free and Pro
Use the full core app for free.
Pro is a one-time upgrade for people who survey Wi-Fi for clients: clean exports with your details and logo, PDF reports, multiple projects and floors, before and after comparisons, live readings with the helper app, and commercial use.
Questions
Who is it for?
- Home. Find the rooms where video calls stutter, and check whether moving the router or adding a mesh node fixed it.
- Small office. See which desks and meeting rooms have weak signal before you buy another access point, then measure again after the change.
- Installers, ISPs and IT teams. Document coverage on site in minutes, before and after your work. Pro adds clean, client-ready exports and live readings.
Is WiFi Heatmapper free?
Yes. Adding a floor plan, measuring, the heatmap and PNG export are free, with no time limit. Free exports carry a watermark. Pro is a one-time upgrade for people who survey Wi-Fi for clients.
Do I need to install anything or create an account?
No. It runs in your browser and there is no sign-up. The optional helper app for live readings is part of Pro and runs on macOS (Apple silicon) and Windows.
Is my floor plan uploaded anywhere?
No. Your floor plan and readings are stored in your browser on your own device. They are not sent to a server.
How do I get the signal strength in dBm?
On a Mac, hold Option and click the Wi-Fi icon in the menu bar and read the RSSI value. On Windows, run "netsh wlan show interfaces" in Command Prompt and use the Rssi value, or the Signal percentage if Rssi is not listed. On Linux, run "iw dev <interface> link". iPhones do not show signal strength in dBm.
What floor plan files can I use?
PNG or JPEG images: a blueprint, a photo of a hand-drawn sketch or a screenshot. If you have no plan, you can sketch the walls in the app.
Can it predict coverage before I install an access point?
No. WiFi Heatmapper maps the signal you measure on site, so thick walls, furniture and neighbors’ networks show up as they really are. A predictive heatmap estimates coverage from a plan before anything is installed; for that, use a predictive planning tool.
What signal strength is good?
-50 dBm or better is excellent. -67 dBm is the minimum Cisco recommends for voice calls over Wi-Fi. Below about -75 dBm, connections get slow and drop.