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Every wall costs signal. Brick and concrete cost the most.
Early accessAll Pro features unlocked until 30 November: live readings, the speed map, PDF reports and more.All Pro features unlocked until 30 November.Pro unlocked until 30 November.
Free WiFi heatmap tool. See where
your Wi-Fi gives up.
- Free, no login
- Measured and predicted maps
- Data stays in your browser
Measured coverage
Signal, as a living surface.
Your real signal, not a guess. Take a few readings and WiFi Heatmapper fills in the map between them: high and green where it's strong, low and red where it drops.
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Doorways let it through, so the far room gets more than you would guess.
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A few readings, and the whole map fills in. Green is strong, red is weak.
How it works
Four steps. About two minutes.
- 01
Add a floor plan
Upload a picture of it, or sketch the walls in the app.
- 02
Measure where you stand
Click your spot and type the signal from your Wi‑Fi menu, or let the helper app read signal and link speed live (Pro).
- 03
Read the map
Green is strong, red is weak. Pale areas still need readings.
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Fix it, then prove it
Try a new router spot in Predicted, move it, then measure again to see the difference.
Predicted view
Drag the router. Watch the coverage move.
Try a new router or mesh spot before you move anything. Drag it and the coverage updates instantly, wall by wall. Switch to Landscape to see strong signal as hills and weak spots as valleys. Then measure to confirm: Pro adjusts the prediction to your real readings.
Who it is for
One floor plan.
Many reasons.
Home
Video calls dropping in one room? See why, and find a better spot for your router.
Small office
Check every desk and meeting room, and see where a mesh point would help before you buy one.
Installers, ISPs, IT teams
Measure on site, show the client the weak spots, and prove the fix afterwards.
Before you drill
Renovating or adding an access point? Draw the walls, place it, and see the coverage first.
Questions
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 ($79, on 2 devices) 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 signal and link speed readings is part of Pro and runs on macOS 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". On iPhone, use Apple's free AirPort Utility with its Wi-Fi Scanner turned on in Settings; on Android, a free app such as WiFiAnalyzer.
What floor plan files can I use?
PNG or JPEG images, or a PDF (its first page is used): 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?
Yes, as an estimate. Mark your router, extenders or mesh points, set the scale and draw the walls, then switch the map to Predicted and drag a device to see how coverage changes. Predictions are typically within 8 to 10 dB; measuring on site shows the real signal, and Pro adjusts the prediction to your readings.
Why measure instead of only predicting?
A prediction only knows the walls you draw, so it is typically within 8 to 10 dB. Measuring shows the real signal, including furniture, appliances and neighbours' networks. WiFi Heatmapper does both, and Pro adjusts the prediction to your readings.
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.