Documentation sections

5G NR Link Budget Calculator — 3GPP TR 38.901 Path Loss, SINR & Range

POSThttps://rftools.io/api/py/v1/calculate

Slug 5g-nr-link-budget. A 5G NR link budget on the 3GPP channel models: TR 38.901 path loss for rural macro, urban macro, urban micro and indoor office, LOS or NLOS, the noise floor from the resource blocks, SINR, link margin, the maximum range inside the model's validity and the TS 38.306 peak data rate.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of 5g-nr-link-budget
Name	Unit	Range	Default	Description
scenarionumber	none	0 … 3	1	3GPP TR 38.901 deployment: 0 rural macro, 1 urban macro, 2 urban micro street canyon, 3 indoor office
lineOfSightnumber	none	0 … 1	0	Whether the direct path is clear; NLOS takes the larger of the LOS and NLOS formulas
frequencynumber	GHz	at least 0.1	3.5	Centre frequency; TR 38.901 covers 0.5 to 100 GHz (30 GHz for RMa)
channelBandwidthnumber	MHz	at least 3	100	UE channel bandwidth; sets the resource blocks and so the noise bandwidth
scsnumber	kHz	at least 15	30	15, 30 or 60 kHz in FR1; 60 or 120 kHz in FR2
bsHeightnumber	m	at least 1	25	TR 38.901 fixes 25 m for UMa and 10 m for UMi; RMa covers 10 to 150 m
utHeightnumber	m	at least 0.5	1.5	User terminal height; 1.5 m at street level
distancenumber	m	at least 1	500	Ground distance from the base station to the user
txPowernumber	dBm	any	46	Total conducted power over the carrier (46 dBm is 40 W)
txGainnumber	dBi	any	17	Transmit Antenna Gain
rxGainnumber	dBi	any	0	Receive Antenna Gain
lossesnumber	dB	at least 0	3	Cable, Body & Other Losses
shadowMarginnumber	dB	at least 0	8	Margin held back for shadowing; compare the scenario's σ_SF output
noiseFigurenumber	dB	at least 0	7	Receiver Noise Figure
requiredSinrnumber	dB	any	0	SINR the chosen modulation and coding needs
interferenceMarginnumber	dB	at least 0	3	Rise of noise plus interference over thermal noise
layersnumber	none	1 … 8	4	MIMO Layers
modulationOrdernumber	none	1 … 10	8	Modulation Order (bits per symbol)
scalingFactornumber	none	0.1 … 1	1	UE capability scaling factor in TS 38.306: 1, 0.8, 0.75 or 0.4
linkDirectionnumber	none	0 … 1	0	Sets the TS 38.306 overhead: 0.14 DL and 0.08 UL in FR1, 0.18 and 0.10 in FR2
extraLossCountnumber	none	0 … 6	0	How many further losses the link adds, such as building entry, foliage, body or polarisation mismatch (0–6)
extraLoss1number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch
extraLoss2number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch
extraLoss3number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch
extraLoss4number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch
extraLoss5number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch
extraLoss6number	dB	0 … 50	0	A further loss on the link, such as building entry, foliage, body loss or polarisation mismatch

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of 5g-nr-link-budget
Field	Unit	Description
linkMarginheadline	dB	Link Margin
pathLoss	dB	Path Loss (TR 38.901)
receivedPower	dBm	Received Power
sinr	dB	SINR (Median)
maxPathLoss	dB	Maximum Allowable Path Loss
maxRange	m	Maximum Range (2-D, Within Model Validity)
resourceBlocks	none	Resource Blocks (N_RB)
occupiedBandwidth	MHz	Occupied Bandwidth (N_RB × 12 × SCS)
thermalNoise	dBm	Thermal Noise (kTB)
noiseFloor	dBm	Receiver Noise Floor (kTB + NF)
breakpointDistance	m	Breakpoint Distance
shadowFadingStd	dB	Shadow-Fading Std (σ_SF)
peakDataRate	Mbps	Peak Data Rate (TS 38.306)
totalLoss	dB	The cable and other losses, the path loss and every extra loss, added

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "5g-nr-link-budget",
    "inputs": {
      "scenario": 1,
      "lineOfSight": 0,
      "frequency": 3.5,
      "channelBandwidth": 100,
      "scs": 30,
      "bsHeight": 25,
      "utHeight": 1.5,
      "distance": 500,
      "txPower": 46,
      "txGain": 17,
      "rxGain": 0,
      "losses": 3,
      "shadowMargin": 8,
      "noiseFigure": 7,
      "requiredSinr": 0,
      "interferenceMargin": 3,
      "layers": 4,
      "modulationOrder": 8,
      "scalingFactor": 1,
      "linkDirection": 0,
      "extraLossCount": 0,
      "extraLoss1": 0,
      "extraLoss2": 0,
      "extraLoss3": 0,
      "extraLoss4": 0,
      "extraLoss5": 0,
      "extraLoss6": 0
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("5g-nr-link-budget", {
    "scenario": 1,
    "lineOfSight": 0,
    "frequency": 3.5,
    "channelBandwidth": 100,
    "scs": 30,
    "bsHeight": 25,
    "utHeight": 1.5,
    "distance": 500,
    "txPower": 46,
    "txGain": 17,
    "rxGain": 0,
    "losses": 3,
    "shadowMargin": 8,
    "noiseFigure": 7,
    "requiredSinr": 0,
    "interferenceMargin": 3,
    "layers": 4,
    "modulationOrder": 8,
    "scalingFactor": 1,
    "linkDirection": 0,
    "extraLossCount": 0,
    "extraLoss1": 0,
    "extraLoss2": 0,
    "extraLoss3": 0,
    "extraLoss4": 0,
    "extraLoss5": 0,
    "extraLoss6": 0,
})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "5g-nr-link-budget",
    "inputs": {
      "scenario": 1,
      "lineOfSight": 0,
      "frequency": 3.5,
      "channelBandwidth": 100,
      "scs": 30,
      "bsHeight": 25,
      "utHeight": 1.5,
      "distance": 500,
      "txPower": 46,
      "txGain": 17,
      "rxGain": 0,
      "losses": 3,
      "shadowMargin": 8,
      "noiseFigure": 7,
      "requiredSinr": 0,
      "interferenceMargin": 3,
      "layers": 4,
      "modulationOrder": 8,
      "scalingFactor": 1,
      "linkDirection": 0,
      "extraLossCount": 0,
      "extraLoss1": 0,
      "extraLoss2": 0,
      "extraLoss3": 0,
      "extraLoss4": 0,
      "extraLoss5": 0,
      "extraLoss6": 0
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "5g-nr-link-budget",
	  "inputs": {
	    "scenario": 1,
	    "lineOfSight": 0,
	    "frequency": 3.5,
	    "channelBandwidth": 100,
	    "scs": 30,
	    "bsHeight": 25,
	    "utHeight": 1.5,
	    "distance": 500,
	    "txPower": 46,
	    "txGain": 17,
	    "rxGain": 0,
	    "losses": 3,
	    "shadowMargin": 8,
	    "noiseFigure": 7,
	    "requiredSinr": 0,
	    "interferenceMargin": 3,
	    "layers": 4,
	    "modulationOrder": 8,
	    "scalingFactor": 1,
	    "linkDirection": 0,
	    "extraLossCount": 0,
	    "extraLoss1": 0,
	    "extraLoss2": 0,
	    "extraLoss3": 0,
	    "extraLoss4": 0,
	    "extraLoss5": 0,
	    "extraLoss6": 0
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "5g-nr-link-budget",
  "values": {
    "linkMargin": 6.134701907799126,
    "pathLoss": 129.9158338083485,
    "receivedPower": -69.91583380834851,
    "sinr": 14.13470190779914,
    "maxPathLoss": 136.05053571614764,
    "maxRange": 718.1162910484755,
    "resourceBlocks": 273,
    "occupiedBandwidth": 98.28,
    "thermalNoise": -94.05053571614765,
    "noiseFloor": -87.05053571614765,
    "breakpointDistance": 560.3876799328955,
    "shadowFadingStd": 6,
    "peakDataRate": 2337.00012,
    "totalLoss": 132.9158338083485
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:5g-nr-link-budget",
    "version": "api@3f2c1a9b04de",
    "formulaRef": "3GPP TR 38.901 V17.0.0, Table 7.4.1-1; TS 38.101-1 V18.15.0 Table 5.3.2-1; TS 38.306 V18.11.0, §4.1.2",
    "assumptions": [
      {
        "code": "tr38901-median-path-loss",
        "text": "Path loss is the median of the 3GPP TR 38.901 V17.0.0 Table 7.4.1-1 model for the chosen scenario and line-of-sight state; shadowing is covered only by the margin entered, and the LOS probability is not applied."
      },
      {
        "code": "effective-environment-height",
        "text": "UMa and UMi use an effective environment height of 1 m, and RMa the default building height of 5 m and street width of 20 m."
      },
      {
        "code": "exact-speed-of-light",
        "text": "Breakpoint distances use c = 299792458 m/s, where TR 38.901 writes 3.0×10⁸ m/s."
      }
    ],
    "validRange": {
      "status": "inside",
      "bounds": {
        "scenario": {
          "min": 0,
          "max": 3,
          "unit": ""
        },
        "lineOfSight": {
          "min": 0,
          "max": 1,
          "unit": ""
        },
        "frequency": {
          "min": 0.1,
          "max": null,
          "unit": "GHz"
        },
        "channelBandwidth": {
          "min": 3,
          "max": null,
          "unit": "MHz"
        },
        "scs": {
          "min": 15,
          "max": null,
          "unit": "kHz"
        },
        "bsHeight": {
          "min": 1,
          "max": null,
          "unit": "m"
        },
        "utHeight": {
          "min": 0.5,
          "max": null,
          "unit": "m"
        },
        "distance": {
          "min": 1,
          "max": null,
          "unit": "m"
        },
        "txPower": {
          "min": null,
          "max": null,
          "unit": "dBm"
        },
        "txGain": {
          "min": null,
          "max": null,
          "unit": "dBi"
        },
        "rxGain": {
          "min": null,
          "max": null,
          "unit": "dBi"
        },
        "losses": {
          "min": 0,
          "max": null,
          "unit": "dB"
        },
        "shadowMargin": {
          "min": 0,
          "max": null,
          "unit": "dB"
        },
        "noiseFigure": {
          "min": 0,
          "max": null,
          "unit": "dB"
        },
        "requiredSinr": {
          "min": null,
          "max": null,
          "unit": "dB"
        },
        "interferenceMargin": {
          "min": 0,
          "max": null,
          "unit": "dB"
        },
        "layers": {
          "min": 1,
          "max": 8,
          "unit": ""
        },
        "modulationOrder": {
          "min": 1,
          "max": 10,
          "unit": ""
        },
        "scalingFactor": {
          "min": 0.1,
          "max": 1,
          "unit": ""
        },
        "linkDirection": {
          "min": 0,
          "max": 1,
          "unit": ""
        },
        "extraLossCount": {
          "min": 0,
          "max": 6,
          "unit": ""
        },
        "extraLoss1": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        },
        "extraLoss2": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        },
        "extraLoss3": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        },
        "extraLoss4": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        },
        "extraLoss5": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        },
        "extraLoss6": {
          "min": 0,
          "max": 50,
          "unit": "dB"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "scenario": 1,
      "lineOfSight": 0,
      "frequency": 3.5,
      "channelBandwidth": 100,
      "scs": 30,
      "bsHeight": 25,
      "utHeight": 1.5,
      "distance": 500,
      "txPower": 46,
      "txGain": 17,
      "rxGain": 0,
      "losses": 3,
      "shadowMargin": 8,
      "noiseFigure": 7,
      "requiredSinr": 0,
      "interferenceMargin": 3,
      "layers": 4,
      "modulationOrder": 8,
      "scalingFactor": 1,
      "linkDirection": 0,
      "extraLossCount": 0,
      "extraLoss1": 0,
      "extraLoss2": 0,
      "extraLoss3": 0,
      "extraLoss4": 0,
      "extraLoss5": 0,
      "extraLoss6": 0
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "scenario"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator page5G NR Link Budget Calculator — 3GPP TR 38.901 Path Loss, SINR & Range, at these values