What is an ARFCN?
ARFCN means Absolute Radio Frequency Channel Number. In a 2G GSM network, it identifies a radio channel. Select the matching GSM band because the same channel number can mean different frequencies in different bands. For example, ARFCN 512 belongs to both DCS 1800 and PCS 1900, but the frequencies are different.
How to use this GSM ARFCN calculator
- Select the GSM band used by the network or measurement.
- Choose ARFCN → Frequency and enter a whole channel number, or choose Frequency → ARFCN and enter a channel center frequency in MHz.
- Read the uplink and downlink pair. The result also shows the duplex spacing and the selected ARFCN.
GSM bands and valid ARFCN ranges
| GSM band | ARFCN range | Uplink (MHz) | Downlink (MHz) | Duplex spacing |
|---|---|---|---|---|
| GSM 850 | 128–251 | 824.2–848.8 | 869.2–893.8 | 45 MHz |
| GSM 900 Primary (P-GSM) | 1–124 | 890.2–914.8 | 935.2–959.8 | 45 MHz |
| GSM 900 Extended (E-GSM) | 0–124 and 975–1023 | 880.2–914.8* | 925.2–959.8* | 45 MHz |
| DCS 1800 | 512–885 | 1710.2–1784.8 | 1805.2–1879.8 | 95 MHz |
| PCS 1900 | 512–810 | 1850.2–1909.8 | 1930.2–1989.8 | 80 MHz |
*E-GSM uses two channel-number blocks. The low-frequency extension is ARFCN 975–1023; ARFCN 0–124 overlaps the P-GSM 900 channel block.
GSM ARFCN frequency formulas
GSM channel spacing is 200 kHz (0.2 MHz). For a selected band, the uplink carrier frequency is calculated from that band’s ARFCN formula. The downlink carrier is the uplink plus the band’s duplex spacing.
- GSM 850: Uplink = 824.2 + 0.2 × (ARFCN − 128); downlink = uplink + 45 MHz.
- P-GSM 900: Uplink = 890 + 0.2 × ARFCN; downlink = uplink + 45 MHz.
- E-GSM 900: for ARFCN 0–124, uplink = 890 + 0.2 × ARFCN; for 975–1023, uplink = 890 + 0.2 × (ARFCN − 1024); downlink = uplink + 45 MHz.
- DCS 1800: Uplink = 1710.2 + 0.2 × (ARFCN − 512); downlink = uplink + 95 MHz.
- PCS 1900: Uplink = 1850.2 + 0.2 × (ARFCN − 512); downlink = uplink + 80 MHz.
Example: GSM 850 ARFCN 128
For GSM 850 channel 128, the uplink is 824.2 + 0.2 × (128 − 128) = 824.2 MHz. Add the 45 MHz duplex spacing to get a downlink of 869.2 MHz.
FAQ on ARFCN Calculator
ARFCN stands for Absolute Radio Frequency Channel Number. It is the channel number used to identify a GSM radio carrier.
In GSM, the channel spacing is 200 kHz (0.2 MHz).
Yes. LTE uses EARFCN and 5G uses NR-ARFCN.
Standard GSM 900 supports 124 radio channels using ARFCN range 1 to 124. Each GSM channel uses 200 kHz spacing. Extended GSM (E-GSM 900) provides additional channels using ARFCN range 975–1023.
A GSM channel number is called an ARFCN (Absolute Radio Frequency Channel Number). It is a unique number assigned to each GSM radio frequency channel used for communication between the mobile station and base station. Instead of using raw frequency values, GSM networks use ARFCN numbers for frequency planning, channel allocation, and RF optimization.