RF Planning Tool

LoRa Mesh Capacity Calculator

Estimate airtime at the busiest point in a mesh. Compare radio settings, reporting rates, routing behavior, and operational headroom before deployment.

Planning model · September 2026

Radio preset

Nodes in the busy area

Report interval per node

Existing channel load

Measured or estimated utilization from other traffic and RF activity.

PLI report window

Sets the maximum report interval above. Current firmware may coerce default-channel broadcasts to a 5-minute minimum; Smart Position can send sooner when movement thresholds are met.

Position message format

Meshtastic normally sends a compact protobuf Position, not an NMEA sentence.

Network shape

How many copies of one report the busiest listener is likely to hear, including the original.

Advanced assumptions

Application data

Useful message content before protocol framing. Traffic profiles set this automatically; edit it here to model a custom payload.

Delivery and retry allowance

1.0× is ideal one-way delivery. Increase this for acknowledgments, retries, route discovery, or movement.

Hop limit

Used only when Network shape is set to Custom relay model.

Audible relays per hop

Used only by the custom relay model.

Estimated framing per packet (bytes)

Radio header and encoded Meshtastic data fields. Default: 20 bytes.

Modeled channel utilization

Comfortable

10%25% planning ceiling

Capacity at this collision domain

Calculated airtime plus the routing and delivery assumptions selected at left.

Nodes against report interval

Select a cell to load that scenario. Values are modeled utilization percentages.

How to read this model

Calculated: LoRa symbol duration and packet airtime for the selected modulation, 16-symbol preamble, explicit header, CRC enabled, and low-data-rate optimization where required.
Assumed: observable relays, independent RF cells, protocol overhead, delivery/retry allowance, and existing background load.
Planning ceiling: 25% is an operational headroom target, not a physical cutoff. Networks may degrade earlier or continue operating above it with increasing latency and loss.
Collision estimate: the pure-ALOHA reference uses e^−2G. Real performance varies with CAD/listen-before-talk, hidden nodes, capture effect, synchronized reporting, packet lengths, and interference.

Protocol-specific assumptions

Meshtastic: observable transmissions are modeled as one origin plus hop limit × average audible relays per hop. Actual managed flooding and suppression depend on topology, roles, link quality, and contention. Native position reports are protobuf messages; the NMEA choices model the cost of carrying text sentences through the mesh and are not native Meshtastic wire formats.
MeshCore: clients do not normally relay. Floods are modeled as one origin plus each audible repeater; learned paths use the selected number of audible transmissions. The model enforces a 184-byte application payload per frame and repeats overhead on every frame.
Reticulum: data follows the selected audible path and cell split. Announces use the documented 167-byte wire size; locally originated announces are added separately, while propagated announces are capped at the default 2% interface allocation.

Limits and sources

This is a planning model, not a coverage or packet-delivery forecast. It does not simulate terrain, antenna systems, regional duty-cycle rules, legal power limits, fading, near/far capture, scheduling, half-duplex blocking, or heterogeneous packet lengths.

Reference material: Semtech LoRa Calculator, Meshtastic preset definitions, MeshCore packet format, and Reticulum interface documentation.