Upload a floor plan (PNG, JPG or PDF), mark the walls, place your access points, and see where the signal reaches, room by room, predicted from what each wall really costs. No download, no signup, and the floor plan never leaves your device.
Two kinds of WiFi heatmap
A WiFi heatmap is a floor plan coloured by signal strength. A measured one comes from walking the building with a survey app, recording what an installed network does. A predicted one is computed from the plan, the wall materials and the access points, so it works before anything is installed. That is the one this tool makes, and the reason it can run in a browser.
Measured — site survey
Predicted — this tool
They come in sequence, not as rivals: predict, install, then measure what got built. The longer version is in Can a WiFi heatmap work in a browser?
Looking for Ekahau HeatMapper?
For years Ekahau HeatMapper was the free WiFi heatmap: a Windows program you carried around a site to record signal. Its last build dates from 2017, and Ekahau's HeatMapper page now redirects to its paid products. NetSpot's free edition is Inspector mode only, with no survey and no export. If the heatmap you want is the one that says where the access points should go, you don't need a survey at all.
| Tool | In a browser | Predicts before install | Price |
|---|---|---|---|
| WiFi Heatmap (this site) Unlimited access points while you plan; free exports include five | Yes | Yes | Free · Pro from €9 |
| Ekahau HeatMapper Windows-only, survey-based, last built 2017 | No | No | Free |
| NetSpot Free Inspector mode only — no planning, no survey, no export | No | No | Free |
The full field, paid tools included, is in Free Ekahau alternatives in 2026.
How it works
A PNG, JPG or PDF. Set the scale from one wall you know the length of, so distances are real metres.
Trace walls by material, or let the editor detect them from the plan. Pick from 41 access-point models across 11 vendors, or enter your own.
Signal renders live at 2.4, 5 or 6 GHz, with a −67 dBm usable-coverage line. Move an access point and watch the dead zones move. Export the map as a PNG.
What the heatmap is made of
For every point on the plan, the editor traces the line to each access point, adds the free-space loss for the distance, and subtracts every wall the line crosses. This is the COST-231 multi-wall model, the approach commercial planners use at their entry tier. These are the losses it applies per wall:
| Wall | 2.4 GHz | 5 GHz | 6 GHz |
|---|---|---|---|
| Drywall | 3 dB | 4 dB | 5 dB |
| Wood | 4 dB | 6 dB | 7 dB |
| Glass | 2 dB | 3 dB | 4 dB |
| Brick | 8 dB | 11 dB | 13 dB |
| Concrete | 15 dB | 20 dB | 23 dB |
| Coated / low-E glass | 20 dB | 25 dB | 28 dB |
So at 5 GHz one brick wall costs 11 dB where a drywall partition costs 4, which is why a heatmap that ignores materials looks fine on screen and fails in the kitchen. Expect predictions within about ±6–10 dB in homes and small offices. The method, and what it deliberately leaves out, is on the accuracy page.
Free: as many access points as you like while you plan; the PNG export includes the first five, on one floor, with a watermark. Pro (€9 for a 7-day pass, €39 once, or €29/year) exports every access point on every floor without the watermark, and adds the branded client PDF report.
See pricingFAQ
Yes. WiFi Heatmap (wifiheatmap.app) makes predicted WiFi heatmaps free in your browser: upload a floor plan, mark the walls by material, place access points, and the coverage map renders as you work. There is no signup and no time limit. You can place as many access points as you like; the free PNG export includes the first five, on one floor, with a watermark. The classic free tool, Ekahau HeatMapper, is a Windows program last built in 2017, and NetSpot's free edition is Inspector mode only, with no survey and no export.
Yes, if it is a predicted heatmap. A browser cannot scan for radios, so a measured heatmap needs an installed app and someone walking the site. A predicted heatmap is computed from your floor plan, the wall materials and the access-point models, so it runs entirely in the browser tab, and your floor plan stays on your device. It needs a laptop or desktop screen; on a phone the site offers to send you the link for later.
HeatMapper was Ekahau's free Windows tool for walking a site and recording signal into a heatmap. Its last build, 1.1.4, dates from 2017, and Ekahau's HeatMapper page now redirects to its paid heatmap products. It measured networks that already existed; it never predicted coverage before an install. For planning, WiFi Heatmap is a free alternative that runs in the browser.
Predicted, when you are deciding where access points go: before buying, before drilling, or before adding one more. Measured, when you need proof of what an installed network actually does, for example at a hand-over. Professionals use both in that order: plan with a prediction, install, then verify on site.
WiFi Heatmap uses the COST-231 multi-wall model: free-space loss plus the attenuation of every wall the signal crosses, by material and by band. Expect about ±6–10 dB in homes and small offices. Large metal structures, lift shafts and dense server racks are where predictions miss most. The method and its limits are documented on the accuracy page.
Yes. Upload a PNG, a JPG or a PDF. For a PDF the editor uses the first page; if your plan is on another page, save that page as an image and upload it.
41 access-point models from 11 vendors, with their datasheet transmit power and antenna gain, across 2.4, 5 and 6 GHz, or enter your own figures. Nothing ties you to one brand: you can mix vendors on the same floor.
Keep reading
How many access points do I need? →
Coverage and capacity, worked through with the same engine as the heatmap.
Can a WiFi heatmap work in a browser? →
What a browser can and cannot do, and what prediction honestly costs.
Free Ekahau alternatives in 2026 →
Every free and paid option compared, including the ones that need no setup.
How accurate is the model? →
The COST-231 multi-wall engine explained, with its ±6–10 dB envelope.
Upload your floor plan, place the access points, and read the heatmap in a few minutes. Free, in your browser, no signup.