Wireless Interference Calculator
Turn signal, co-channel, adjacent-channel and noise-floor levels into SNR, SINR and the modulation the link can actually hold.
Inputs
SINR
13.82dB
SNR (Interference Ignored)
33.0dB
Loss Caused by Interference
19.18dB
Highest Sustainable Modulation
MCS 1 — QPSK 1/2
Step by step
Values used
Wanted signal level = -62 dBm; Strongest co-channel interferer = -78 dBm; Strongest adjacent-channel interferer = -70 dBm; Adjacent-channel rejection = 10 dB; Noise floor = -95 dBm
Wireless Interference
SINR = 10·log10(S ÷ (I_co + I_adj + N)) with every level converted from dBm to milliwatts first; adjacent-channel power is reduced by the receiver's rejection figure.
SINR
= 13.82 dB
SNR (Interference Ignored)
= 33.0 dB
Loss Caused by Interference
= 19.18 dB
Highest Sustainable Modulation
= MCS 1 — QPSK 1/2
How it works
Decibel values cannot be added, so each level is converted to linear power, the interference and noise terms are summed, and the ratio is converted back to dB. Adjacent-channel energy is attenuated by the receiver filter, which is why co-channel interference hurts far more. Survey tools report signal strength, but clients choose their modulation from SINR, which is why a strong -62 dBm signal can still deliver BPSK throughput on a contended channel.
Formula
Wireless Interference
SINR = 10·log10(S ÷ (I_co + I_adj + N)) with every level converted from dBm to milliwatts first; adjacent-channel power is reduced by the receiver's rejection figure.
- S
- Wanted signal power in mW
- I_adj
- Adjacent-channel power after rejection
- N
- Thermal and ambient noise power
Frequently Asked Questions
How is Wireless Interference calculated?
SINR = 10·log10(S ÷ (I_co + I_adj + N)) with every level converted from dBm to milliwatts first; adjacent-channel power is reduced by the receiver's rejection figure. Decibel values cannot be added, so each level is converted to linear power, the interference and noise terms are summed, and the ratio is converted back to dB. Adjacent-channel energy is attenuated by the receiver filter, which is why co-channel interference hurts far more.
Why does Wireless Interference matter?
Survey tools report signal strength, but clients choose their modulation from SINR, which is why a strong -62 dBm signal can still deliver BPSK throughput on a contended channel.
What values do I need to enter?
This calculator takes 5 inputs: Wanted signal level, Strongest co-channel interferer, Strongest adjacent-channel interferer, Adjacent-channel rejection, Noise floor. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.