Signal Strength Guide

How to Check Your Actual Cell Signal Strength

Your signal bars are lying. Every manufacturer maps them differently, and each bar hides a 10x difference in actual power. Here's how to see the real numbers in 30 seconds.

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Three Numbers That Actually Matter

Forget signal bars. These are the metrics that tell you what is really happening.

  • RSRP: Signal Strength

    Raw power from the tower reaching your phone. Always negative. Closer to zero means stronger signal.

  • SINR: Signal Quality

    How much stronger your signal is vs. interference. Higher is better. Reliable on 5G and Android. iPhone LTE readings are often inaccurate. Use RSRP and RSRQ instead.

  • RSRQ: Connection Quality

    How congested your connection is. Explains "full bars but nothing loads." Closer to zero is better.

The Scale That Surprises Everyone

Decibels are logarithmic. Every 10 dB = 10x the power, and every 3 dB is a doubling. So -90 dBm is literally ten times stronger than -100 dBm. A small number change makes a huge real-world difference.

Signal Strength Reference Chart

Use this chart to interpret your RSRP, SINR, and RSRQ readings.

Rating RSRP — Strength SINR — Signal Quality * RSRQ — Connection Quality
Excellent -80 dBm or better Above 10 dB -10 dB or better
Good -80 to -90 dBm 5 to 10 dB -10 to -15 dB
Fair -90 to -100 dBm 0 to 5 dB -15 to -20 dB
Poor -100 to -110 dBm Below 0 dB Below -20 dB
Very Weak Below -110 dBm — —

Industry reference ranges. Your experience depends on carrier, location, and tower congestion.

*SINR is reliable on 5G (all phones) and on Android (LTE and 5G). iPhone LTE SINR readings are often inaccurate and should be ignored. Use RSRP and RSRQ on iPhone LTE.

What Your Numbers Are Telling You

Three common scenarios and what to do about each one.

  • Weak but Clean Signal

    RSRP around -100 dBm with RSRQ above -12 dB? Clean signal, just too weak indoors. Ideal for a signal booster.

  • Strong but Slow

    RSRP in the -80 to -90 range but still slow? Likely tower congestion. You are sharing bandwidth with too many users.

  • Weak + Interference

    RSRP below -100 dBm and RSRQ below -15 dB? Edge of coverage with heavy interference. A booster can help if signal exists outside.

How to Get Your Signal Reading

Step-by-step for every phone. Takes about 30 seconds.

iPhone: Field Test Mode (iOS 18+)

Step 1: Open the Phone app and go to the Keypad.

Step 2: Dial *3001#12345#* and tap the green call button.

Step 3: The Dashboard opens immediately, showing your carrier info at the top and your signal metrics below.

  • 5G: You will see a single SNR reading. This one is reliable. Higher is better.
  • LTE: Focus on RSRP and RSRQ. The SINR0 and SINR1 values shown for LTE are often inaccurate on iPhone.

Important: No third-party app can show dBm on iPhone. Apple blocks it. Field Test Mode is the only way.

To exit Field Test Mode, just swipe up from the bottom of the screen.

Samsung Galaxy (Android)

Step 1: Open the Phone app and dial *#0011#

Step 2: Service Mode launches automatically, showing RSRP, RSRQ, SINR, band, and frequency.

Galaxy S24 / S25: Disable Auto Blocker first. Settings > Security & Privacy > Auto Blocker > toggle off. On some carrier-locked models, the code may not work even with Auto Blocker off.

Every Other Android Phone

The most reliable approach is a free app. We have tested the main options and two stand out:

NetMonster
Shows RSRP, RSRQ, SINR for 4G & 5G. Identifies tower, band, frequency. Tells you if you are on real standalone 5G or 4G-backed 5G.

Network Cell Info Lite
More visual. Gauge displays and signal-over-time graphs. Great for mapping where signal is strongest in your building.

Basic Settings Path (RSRP only):
Pixel: Settings > About Phone > SIM Status
Samsung: Settings > About Phone > Status Information > SIM Card Status
OnePlus: Settings > About Phone > Status > SIM Status

What about *#*#4636#*#*?
This code still works on Google Pixel (Android 15), but Samsung has blocked it on newer Galaxy phones. Do not count on it unless you have a Pixel.

Is Your Signal Boostable?

We have helped thousands of customers fix weak signal over 13+ years. If your outside reading shows signal exists, a booster can bring it inside. Not sure? Call us and we will tell you in 2 minutes.

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