Documentation sections

5G NR Band Lookup — n78 Frequencies, NR-ARFCN & Resource Blocks

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

Slug 5g-nr-band-lookup. Look up any 5G NR operating band from 3GPP Release 18: uplink and downlink frequencies, duplex spacing, the band's NR-ARFCN range, NR-ARFCN to frequency and back, and the resource blocks for a channel bandwidth and subcarrier spacing.

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-band-lookup
Name	Unit	Range	Default	Description
bandnumber	none	at least 1	78	The band number without its n, from TS 38.101-1 (FR1) or TS 38.101-2 (FR2): 78 for n78, 257 for n257
channelBandwidthnumber	MHz	at least 3	100	UE channel bandwidth; FR1 runs from 3 to 100 MHz, FR2 from 50 to 2000 MHz
scsnumber	kHz	at least 15	30	15, 30 or 60 kHz in FR1; 60 or 120 kHz in FR2 (480 and 960 kHz in n263)
arfcnnumber	none	at least 0	636666	The channel number to convert to frequency, 0 to 3279165 on the global raster
frequencynumber	MHz	at least 0	3549.99	A frequency to convert to the nearest NR-ARFCN

Outputs

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

Outputs of 5g-nr-band-lookup
Field	Unit	Description
arfcnFrequencyheadline	MHz	NR-ARFCN Frequency
frequencyRange	none	Frequency Range (1 = FR1, 2 = FR2)
dlLow	MHz	Downlink Low Edge
dlHigh	MHz	Downlink High Edge
ulLow	MHz	Uplink Low Edge
ulHigh	MHz	Uplink High Edge
duplexSpacing	MHz	Duplex Spacing, DL − UL (0 = TDD)
dlArfcnFirst	none	Downlink NR-ARFCN, First
dlArfcnLast	none	Downlink NR-ARFCN, Last
ulArfcnFirst	none	Uplink NR-ARFCN, First
ulArfcnLast	none	Uplink NR-ARFCN, Last
channelRaster	kHz	Finest Channel Raster
resourceBlocks	none	Resource Blocks (N_RB)
transmissionBandwidth	MHz	Transmission Bandwidth (N_RB × 12 × SCS)
frequencyArfcn	none	NR-ARFCN of the Frequency

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-band-lookup",
    "inputs": {
      "band": 78,
      "channelBandwidth": 100,
      "scs": 30,
      "arfcn": 636666,
      "frequency": 3549.99
    }
  }'

import rftools

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

result = client.calculate("5g-nr-band-lookup", {
    "band": 78,
    "channelBandwidth": 100,
    "scs": 30,
    "arfcn": 636666,
    "frequency": 3549.99,
})
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-band-lookup",
    "inputs": {
      "band": 78,
      "channelBandwidth": 100,
      "scs": 30,
      "arfcn": 636666,
      "frequency": 3549.99
    }
  }),
});
console.log(response.status, await response.json());

package main

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

func main() {
	body := []byte(`{
	  "slug": "5g-nr-band-lookup",
	  "inputs": {
	    "band": 78,
	    "channelBandwidth": 100,
	    "scs": 30,
	    "arfcn": 636666,
	    "frequency": 3549.99
	  }
	}`)
	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-band-lookup",
  "values": {
    "arfcnFrequency": 3549.99,
    "frequencyRange": 1,
    "dlLow": 3300,
    "dlHigh": 3800,
    "ulLow": 3300,
    "ulHigh": 3800,
    "duplexSpacing": 0,
    "dlArfcnFirst": 620000,
    "dlArfcnLast": 653333,
    "ulArfcnFirst": 620000,
    "ulArfcnLast": 653333,
    "channelRaster": 15,
    "resourceBlocks": 273,
    "transmissionBandwidth": 98.28,
    "frequencyArfcn": 636666
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:5g-nr-band-lookup",
    "version": "api@3f2c1a9b04de",
    "formulaRef": "3GPP Release 18: TS 38.101-1 V18.15.0 and TS 38.101-2 V18.14.0, Tables 5.2-1, 5.3.2-1 and 5.4.2.3-1; TS 38.104 V18.15.0, Table 5.4.2.1-1",
    "assumptions": [
      {
        "code": "release-18-tables",
        "text": "Bands, NR-ARFCN ranges and N_RB come from the 3GPP Release 18 tables (TS 38.101-1 V18.15.0, TS 38.101-2 V18.14.0, TS 38.104 V18.15.0); a band added in a later release is reported as unknown."
      },
      {
        "code": "general-nrb-table",
        "text": "N_RB is read from the general table for the bandwidth and subcarrier spacing; whether the band allows that bandwidth (Table 5.3.5-1) is not checked."
      }
    ],
    "validRange": {
      "status": "inside",
      "bounds": {
        "band": {
          "min": 1,
          "max": null,
          "unit": ""
        },
        "channelBandwidth": {
          "min": 3,
          "max": null,
          "unit": "MHz"
        },
        "scs": {
          "min": 15,
          "max": null,
          "unit": "kHz"
        },
        "arfcn": {
          "min": 0,
          "max": null,
          "unit": ""
        },
        "frequency": {
          "min": 0,
          "max": null,
          "unit": "MHz"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "band": 78,
      "channelBandwidth": 100,
      "scs": 30,
      "arfcn": 636666,
      "frequency": 3549.99
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "band"
      ],
      "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 Band Lookup — n78 Frequencies, NR-ARFCN & Resource Blocks, at these values