WiFi Coverage Simulator

Draw your floor plan, place access points and Zigbee devices, and visualize wireless signal strength with an interactive heatmap. Plan your WiFi and smart-home mesh network before you install it.

Click anywhere on the floor plan to inspect the predicted signal strength at that location.

Excellent (>-65 dBm) Good (-65 to -75 dBm) Weak (-75 to -85 dBm) Dead Zone (<-85 dBm)

Signal Inspector

Click on the floor plan to measure signal at any point.

Wall Material

AP Transmit Power

WiFi Standard

Units

Coverage Band View

Target Ideal AP Placement Finder

Automatically finds the minimum number of access points and their optimal positions to guarantee coverage above your chosen signal threshold across the entire floor plan.

Min Signal Threshold

Band for Planning

Max APs

How it works: Draw rooms to auto-create snapping walls. Use Move/Edit to drag items, resize rooms via handles, or adjust sizes numerically. The ideal placement finder uses greedy set-cover to minimize AP count while guaranteeing your signal threshold across the floor plan.

How to Use the WiFi Coverage Simulator

1. Draw Your Floor Plan

Select the Room tool and click-drag on the canvas to outline each room in your home or office. Use the Wall tool to add interior walls between rooms - these affect signal attenuation. Set the correct Wall Material in the settings, since drywall, brick, and concrete absorb very different amounts of signal.

2. Place Your Access Points

Use Place AP to mark where your main router sits. Add Mesh Nodes or repeaters to fill dead zones. The heatmap updates instantly to show where coverage is strong (green) and weak (red). For smart-home setups, place Zigbee devices like bulbs and sensors and watch the mesh form.

3. Inspect Signal Strength

Switch to Inspect mode and click anywhere on the floor plan. The panel shows predicted dBm signal strength, quality rating, the recommended band (2.4 or 5 GHz), wall count on the path, and estimated maximum throughput based on your selected WiFi standard.

Understanding the Results

Excellent (>-65 dBm): Ideal for streaming, video calls, and gaming. Full throughput available.
Good (-65 to -75 dBm): Solid for most tasks. 5 GHz recommended when available.
Weak (-75 to -85 dBm): Marginal. Switch to 2.4 GHz for stability. Consider a mesh node.
Dead Zone (<-85 dBm): Unreliable or no connection. Add a repeater or mesh node here.

FAQ

How accurate is the coverage simulation?

The simulator uses the standard Free Space Path Loss (FSPL) model combined with per-wall attenuation values for common building materials. This gives a useful first approximation for planning AP placement. Real-world performance also depends on interference from neighbors, furniture, appliances (especially microwaves and baby monitors on 2.4 GHz), antenna orientation, ceiling height, and multi-path reflections. Use the results to compare relative coverage between AP placements rather than as an absolute guarantee.

Why does 5 GHz have shorter range than 2.4 GHz?

Higher frequencies attenuate faster through air and especially through walls. FSPL increases with frequency, so 5 GHz loses roughly 7 dB more than 2.4 GHz at the same distance. However, 5 GHz offers more channels, less congestion, and higher data rates, making it preferable for short-range high-bandwidth connections. A common strategy is 5 GHz for speed where possible and 2.4 GHz for range and IoT devices.

How does Zigbee mesh routing work?

Zigbee devices form a mesh network where mains-powered devices (bulbs, smart plugs) act as routers that relay messages for battery-powered end devices (sensors). The simulator computes a path from each Zigbee device back to the coordinator (your first AP placement) through the nearest intermediate Zigbee routers. Each hop has its own signal quality, and adding more mains-powered devices extends and strengthens the mesh.

What is wall attenuation and why does material matter?

Wall attenuation is the signal loss (in dB) that occurs when radio waves pass through a wall. Typical values: drywall loses about 3 dB, wood 4 dB, brick 10 dB, and reinforced concrete 15 dB or more. A signal passing through two brick walls loses 20 dB - a 100x reduction in power. This is why a router in one corner of a brick house often cannot reach the opposite corner, and why mesh systems that place a node in each zone are effective.

Does this tool send my floor plan to a server?

No. All simulation and rendering happens entirely in your browser using HTML5 Canvas and JavaScript. Your floor plan, AP positions, and device placements never leave your device. There is no upload, no account, and no tracking of your layout.

Where should I place my router for best coverage?

Place your main router as close to the center of your home as possible, elevated (on a shelf, not the floor), away from thick walls and metal appliances. For multi-story homes, a central location on the middle floor often covers both levels. If one router cannot cover the whole space, add mesh nodes so that each node has a strong signal to at least one other node - mesh links degrade badly if the nodes are too far apart.