What is an SOS alert?
An SOS alert is a deliberate call for help that you trigger yourself, usually with a button press or a quick sequence of presses. Depending on the tool, it calls emergency services, notifies people you have chosen, or both, and usually shares your location. Phone features like iPhone Emergency SOS call emergency services first; most safety apps alert personal contacts, who then decide what to do.
Two kinds of SOS
The word SOS covers two quite different actions, and it helps to know which one a given button does before you need it.
Emergency services SOS is built into phones and watches. Apple says that on iPhone you press and hold the side button and either volume button until the countdown on Emergency SOS ends (or, if you set it up, press the side button five times), and by default the phone plays a warning sound, counts down and calls emergency services. After the call ends, iPhone texts your emergency contacts your current location and, for a period afterward, sends them updates when it changes. Google says that on Android you press the power button five times or more to start Emergency SOS, and it can share your real-time location with emergency contacts when you have an internet connection.
Contact SOS is what most personal safety apps do. You press a button and the app sends an urgent alert, with your location, to specific people such as a partner, parent or friend. They see where you are and call you, come to you, or call 911 for you.
| Who it reaches | Noise on your end | Needs | |
|---|---|---|---|
| Phone Emergency SOS | Emergency services, then your emergency contacts | Warning sound and countdown by default on iPhone | A way to place an emergency call |
| App contact SOS | The people you chose, with your location | Depends on the app | A data connection and someone watching |
| Silent SOS | Contacts or text-to-911, discreetly | As little as possible | A discreet trigger; text-to-911 where offered |
| Personal safety alarm | Whoever is within earshot | Very loud on purpose | Nothing but the device |
What happens after you press it
A typical contact SOS alert includes your name, the fact that you asked for help, a timestamp and a location link. The best ones keep the location live so your contact can see if you move. The contact's next steps are the part that saves time, which is why our guide on how to respond to an SOS alert is written for the person receiving it.
Holler's SOS is a contact SOS. Pressing it notifies your Guardians by email and push with your location, and they can follow you on the live link in any browser. A Guardian can tap to acknowledge the alert, so you and the other Guardians can see someone is checking; acknowledging does not send help. Holler never contacts 911 or emergency services. If you can call 911 yourself, do that first, then let the SOS bring in the people who know you.
An example: walking home after dark, you twist a knee badly on a dark path and cannot put weight on it. You call 911 and give the street name. Then you press SOS in your safety app, so your partner sees your location, knows an ambulance is coming, and can meet you or the hospital. If you did not know your location to tell the dispatcher, our answer on how to call 911 if you do not know where you are explains what to say.
When an SOS is the right tool
A manual SOS is the most reliable alert there is when you are conscious and can reach your phone, because it does not rely on software guessing what happened. You know something is wrong, and you say so.
- You are injured but awake and can still use your phone
- You feel unsafe because of a person or a situation
- You are lost and getting worried, with signal but no clear way out
- You find someone else hurt and want your people to know where you are
Limits and failure modes
An SOS needs you to trigger it. If you are unconscious, pinned or cannot reach the phone, it will not help, which is why automatic backstops such as a stationary alert or crash detection exist. Our answer on calling for help if you can't reach your phone covers that situation.
A contact SOS also needs a connection. Without cell data, the alert may not leave your phone. A voice call to 911 does not depend on the app's data connection, so if an app alert will not send, try calling 911 directly.
And it needs a person on the other end. Alerts to contacts who have muted notifications, changed numbers or are asleep can go unseen. Choose people who will respond, and tell them what you expect.
SOS compared with nearby concepts
A silent SOS is a call for help that avoids noise or visible attention, used when being overheard could make a situation worse. The table above lays out how it differs.
An overdue alert fires on its own when you miss a return time. An SOS is immediate and intentional.
A personal safety alarm makes a very loud noise to draw attention nearby. It summons whoever is within earshot rather than your contacts far away. Our personal safety alarm explainer covers that tool.
Practice before you need it
Keep a note of what each button does. Mixing up a phone SOS that calls 911 with an app SOS that alerts a friend is an easy mistake under stress.
01Find your phone's SOS setting
Learn the button sequence for your phone and check whether it calls emergency services automatically. See what happens when you use Emergency SOS on an iPhone.
02Check your emergency contacts
The contacts your phone texts after an SOS call come from your emergency settings, not your favorites.
03Know where your app's SOS button is
Open it once when calm, so you are not searching for it under stress.
04Tell your contacts what an SOS means
Agree that it means call now, and call 911 if you do not pick up.
Questions people ask
Does an SOS alert call 911?
Phone Emergency SOS features call emergency services. Many safety apps, including Holler, alert your chosen contacts instead and do not contact 911.
What if I trigger an SOS by mistake?
Phone Emergency SOS gives you a countdown so you can stop the call before it connects. If an emergency call does connect, stay on the line and tell the dispatcher you are OK. For an app SOS, message your contacts right away to say you are fine.
What should my contact do when they get an SOS?
Try calling you, look at your location, and call 911 with that location if they cannot reach you or you asked for help. Our guide on how to respond to an SOS alert walks through it.
What is the difference between SOS and Emergency SOS?
Emergency SOS is the specific name Apple and Android use for their built-in emergency call features. SOS on its own is the general idea of a deliberate call for help.
Keep reading
Sources: Apple Support: Make an emergency call or text on iPhone or Apple Watch, Android Help: Get help during an emergency with your Android phone.