---
title: "Calculates LoRa receiver sensitivity from spreading factor, bandwidth, and noise figure using the Semtech SX1276 datasheet SNR thresholds. Computes the noise floor from thermal noise density (-174 dBm/Hz), channel bandwidth, and receiver noise figure, then adds the spreading-factor-dependent minimum demodulation SNR. Returns sensitivity in dBm, noise floor, required SNR, and thermal noise reference. Essential for link budget planning in LoRaWAN and Meshtastic networks. Feeds sensitivity_dbm to link_budget and lora_range_estimate for end-to-end coverage analysis."
method: POST
path: "/api/lora_sensitivity"
tags: ["mesh"]
---

# Calculates LoRa receiver sensitivity from spreading factor, bandwidth, and noise figure using the Semtech SX1276 datasheet SNR thresholds. Computes the noise floor from thermal noise density (-174 dBm/Hz), channel bandwidth, and receiver noise figure, then adds the spreading-factor-dependent minimum demodulation SNR. Returns sensitivity in dBm, noise floor, required SNR, and thermal noise reference. Essential for link budget planning in LoRaWAN and Meshtastic networks. Feeds sensitivity_dbm to link_budget and lora_range_estimate for end-to-end coverage analysis.

`POST /api/lora_sensitivity`

## Request

- Base URL: `https://calc.engineer`
- URL: `https://calc.engineer/api/lora_sensitivity`
- Auth: none declared

## Request body

- object
  - `sf` number: LoRa spreading factor (7-12). Higher SF = better sensitivity but slower data rate.
  - `bw_khz` unknown
  - `noise_figure_db` number: Receiver noise figure in dB. Typical LoRa radio NF is 6 dB (SX1276).

## Response `200`

Computed result for lora_sensitivity

- object
  - `result` object, required
    - `sensitivity_dbm` number, required: Receiver sensitivity in dBm. The minimum signal power for successful demodulation.
    - `noise_floor_dbm` number, required: Receiver noise floor in dBm, computed from thermal noise, bandwidth, and noise figure.
    - `required_snr_db` number, required: Minimum SNR required for LoRa demodulation at the given spreading factor.
    - `thermal_noise_dbm` number, required: Thermal noise power density at room temperature: -174 dBm/Hz.
  - `tool` string, required
  - `version` string, required
  - `computed_at` string, date-time, required
  - `chain` object, required
    - `feeds` unknown[]
      - unknown
    - `accepts_from` unknown[]
      - unknown

## Other responses

- `400`: Validation error or invalid JSON
- `404`: Tool not found

---

[API](https://skmtc.dev/calc/apis/calc-engineer-api.md) · [All operations](https://skmtc.dev/calc/apis/calc-engineer-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calc/apis/calc-engineer-api/revisions/8830480ec488?raw)