1. The clock: the message is being sent
When you see a small clock next to your message instead of a checkmark, it means WhatsApp hasn't yet managed to send it to its servers. This usually happens due to lack of coverage or an internet connection on your own phone. As soon as you get signal or wifi back, the message will send automatically and the clock will turn into the first checkmark. If the clock stays there for a long time, check that you have mobile data or wifi turned on with a good connection.
2. A gray checkmark: sent to the server
A single gray checkmark means your message has left your phone and reached WhatsApp's servers correctly, but we still don't know if it has reached the other person's phone. This can happen because the recipient's phone is off, out of battery, without an internet connection, or because they have WhatsApp temporarily uninstalled. As soon as their phone connects to the internet, that checkmark will become double.
3. Two gray checkmarks: delivered to the recipient's phone
When two gray checkmarks appear, it means the message has physically reached the phone of the person you're writing to, even though they haven't opened or read it yet. It's confirmation of delivery, not of reading. It's common to see the message in this state for hours if the other person hasn't checked their phone again or has notifications muted.
4. Two blue checkmarks: the message has been read
The two checkmarks turn blue when the recipient has opened the chat and the message has been displayed on their screen. This is the read receipt and it's the state that tends to generate the most doubt and anxiety, especially when someone reads a message and takes a while to reply. Keep in mind that "read" in this context only means the message has been displayed inside the chat, not that the person has understood it or paid attention to it.
5. Why the checkmark sometimes doesn't turn blue even though it's been read
There are situations where someone can read part of your message without you knowing, because the checkmarks stay gray. This mainly happens in two cases. The first is when the recipient reads the content through the notification preview, without needing to open the app or the chat; WhatsApp only marks the message as read when the conversation itself is opened. The second case is when the person has manually turned off read receipts in their privacy settings, something you can also do yourself, which we explain in the next section.
6. How to turn off read receipts and what you lose in exchange
If you'd rather people not know when you read their messages, you can turn off this feature from Settings → Privacy and look for the "Read receipts" option. Turn it off and from that moment your checkmarks will stay gray for your contacts, even if you've read their messages.
The trade-off is that WhatsApp applies this setting both ways: if you turn off your read receipts, you also won't be able to see the blue checkmarks of the people you talk to. In other words, you'll stop knowing whether they've read your messages. There's no way to turn it off just so others can't see you while you keep the information about them.
7. How checkmarks work in a group
In group chats, the double blue checkmark only appears once every member of the group has read the message, not just one or a few. You can see who has read it and who hasn't by pressing and holding the message and checking the detailed info, where WhatsApp breaks down the delivery and read status for each participant. That's why in large groups it's normal for the checkmark to take quite a while to turn blue, or to stay gray indefinitely if someone barely checks the group.