This website gives information on how to get signal strengths for Android phones (as well as iPhones). There are a number of different options:
If connected to WiFi, WiFi needs to be turned off otherwise the signal strength seen will be of the WiFi connection and not the mobile network.
On an Android device I see the same (woefully low) mobile signal strength in Settings > About > SIM status or dialling *#*#4636#*#*, whether wifi’s on or off.
Note that neither option shows signal strength on an Android device without a SIM, so you can’t use this to see if there’s enough signal to make a SIMless emergency call.
Not great here either, depending on which window one is sitting next to. SMS are more reliable than voice.
As an aside, there’s a risk some may mis-interpret better or worse, (high and low). The reference levels are expressed as negative numbers. In which instance -50 is greater than -90! Something the more mathematical and science orientated amongst us will have no difficulty with.
For signal strength the lower the unsigned number the better. Fortunately the guide with the linked article offers;
- Signal Strength (RSRP): This tells you how strong the signal is when it hits your phone. It’s measured in dBm (decibel milliwatts). The numbers usually range from -50 dBm (excellent) to -120 dBm (very weak). The closer your number is to zero, the better your signal.
A caution is if one travels overseas. While Optus offers international roaming services not all MNVO’s do. The option to use WiFi Calling OS may not be supported. It pays to check if important.
SMS can get through on very low signal strengths, as there’s not much bandwidth needed.
Concrete or full brick buildings – maybe also steel-framed? – will block or significantly diminish even reasonably strong mobile signals, unfortunately.
The typical ‘strongest’ signal here (inside or outside) is around -109 dBm, but it’s often dipping lower: I see -116 to -119 quite often. If it weren’t for wifi calling, we’d struggle to make and receive calls at home … in the middle of inner-suburban Canberra. 
I don’t know about that. Also, those instructions don’t exactly match reality. Did you actually try this?
In any case, for me, dial the number – and RSRP and friends just come up on the screen.
(My WiFi signal strength is literally orders of magnitude higher, bels higher as it were. I would know if the phone were somehow jumbling it up and displaying the WiFi signal strength instead. That said, there is no harm in turning off WiFi for the duration of the test as long as you remember to turn it back on again afterwards.)
I agree. That part of the UI is not great but I suppose it is intended for field tests, not general usage. They used in on 730 but without telling people what number to dial, so I thought I would just throw it out there if people want to play with it.
I guess one way of looking at it for the non-science-orientated is … -50⁰ is cold but -90⁰ is colder. Which would you rather?
I have good signal at home (and no reception problems) but I don’t get anywhere near -50 dBm.
ACMA actually says that anything at or above -95 dBm is to be described as “good”. Citation: https://www.legislation.gov.au/F2026L00381/asmade/text
I feel another ACMA debacle coming on but we will see …
(For example, ACMA mandates that MNOs must use modelling rather than actual real-world measurements. MNOs have always used modelling to produce their coverage maps and it has never been 100% accurate but it wasn’t a major issue because it wasn’t specifically being regulated.)
Or copy and paste the number in. Just save the text in notepad for future use.
My four bar result in 4G LTE (there is no 5G around our home area). To get 5G signal we have to go about 2 km away.
Yes. I will clarify my original comment.
Inside or outside?
I can get as ‘warm’ as -80 dBm outside. It can diminish substantially inside, to an RSRP comparable with yours i.e. 100x weaker (which is still perfectly OK for use) - but that will depend on the number of absorbing surfaces in the house, construction material, …
Outside, though inside is only marginally worse at around 110. We are in the middle of the 4G envelope that our area is in. Inside we use the WiFi calling rather than rely on a tower signal.
