Can Senders See If You Opened Their Email?

Last updated: October 23, 2026

Email senders can see if you opened their message using tracking pixels, tiny invisible images embedded in emails. When you open the email, the pixel loads automatically and tells the sender you opened it, when, how many times, what device you used, and roughly where you are. In 2021, an email service analyzed its traffic for the BBC and found that two-thirds of emails to personal accounts contained a spy pixel.

Quick answer: Yes, senders can see if you opened their email by embedding a tracking pixel, a tiny image file as small as 1x1 pixels that loads when you open the message. The pixel can reveal if you opened it, when, how many times, what device you used, and your rough location based on your IP address. You can block tracking pixels in iPhone Mail by going to Settings > Apps > Mail > Privacy Protection and turning on Protect Mail Activity. In Gmail, go to Settings > See all settings > Images section and select "Ask before displaying external images."

Every fact below comes from the BBC News investigation "Spy pixels in emails have become endemic" (February 2021), Apple Support's Mail Privacy Protection guide, Gmail Help, and the Princeton University email tracking study (2018), all accessed October 23, 2026.

#Watch: Can senders see if you opened their email?

This video explains how email tracking pixels work, what they reveal about you, and how to block them on iPhone and Gmail.

#What is an email tracking pixel?

An email tracking pixel, also called a spy pixel, is a tiny image file embedded in an email. According to the BBC's 2021 investigation:

"Tracking pixels are typically a .GIF or .PNG file that is as small as 1x1 pixels, which is inserted into the header, footer or body of an email. Since they often show the colour of the content below, they can be impossible to spot with the naked eye even if you know where to look."

The pixel loads when you open the email. No click required.

#What can tracking pixels reveal?

The BBC's investigation documented what tracking pixels can see. Emails pixels can be used to log:

• if and when an email is opened
• how many times it is opened
• what device or devices are involved
• the user's rough physical location, deduced from their internet protocol (IP) address - in some cases making it possible to see the street the recipient is on

That means a sender can know:

• If you opened it - Yes or no
• When you opened it
• How many times - If you opened it once, twice, or ten times
• What device - Phone, tablet, computer, or multiple devices
• Where you are - Your rough location from your IP address, in some cases down to your street

#How common are tracking pixels?

The use of tracking pixels is "endemic," according to the BBC's 2021 investigation.

Hey, a paid email service, analysed its traffic at the BBC's request and found:

"Hey's review indicated that two-thirds of emails sent to its users' personal accounts contained a 'spy pixel', even after excluding for spam."

Two-thirds. That's the baseline for personal email accounts.

David Heinemeier Hansson, Hey's co-founder, told the BBC:

"On average, every Hey customer receives 24 emails per day that attempt to spy on them. The top 10% of users receive more than 50. We're processing over one million emails a day and we're just a tiny service compared to the likes of Gmail, but that's north of 600,000 spying attempts blocked every day."

#Who uses tracking pixels?

Many of the largest brands use email pixels, according to the BBC. British Airways, TalkTalk, Vodafone, Sainsbury's, Tesco, HSBC, Marks & Spencer, Asos, and Unilever are among UK brands Hey detected using them.

The big tech firms were the exception, the BBC reported.

#Why do senders use tracking pixels?

Tracking pixels serve three purposes:

#1. Campaign performance

Senders use them to track how many emails in a specific campaign are opened in aggregate, as well as to automatically stop sending messages to customers who ignore them.

#2. Customer profiles

According to a Princeton University study published in 2018, about 29% of emails in the study's corpus of commercial mailing-list emails leaked the address (viewed in a full email client). The data gathered from email tracking is sometimes linked to a user's cookies. This allows an individual's email address to be tied to their wider browsing habits, even as they move from one device to another.

The study warned: "The resulting links between identities and web history profiles belie the claim of 'anonymous' web tracking."

#3. Personalized follow-ups

Senders can see that you opened their email and follow up accordingly.

Hansson told the BBC:

"Particularly with salespeople or consultants, they can go: 'I saw you open my email yesterday, but you haven't replied yet. Can I call?' And in some cases they get outright belligerent when they see you've opened it three times but have still not replied."

#How to block tracking pixels on iPhone

Apple Mail on iPhone has a built-in feature called Mail Privacy Protection that blocks tracking pixels.

According to Apple Support:

"Mail Privacy Protection hides your IP address so senders can't link it to your other online activity or determine your exact location. It also prevents senders from seeing if you've opened the email message they sent you."

#Steps to turn on Mail Privacy Protection

1. Go to Settings > Apps > Mail
2. Tap Privacy Protection, then turn on Protect Mail Activity

Note: Mail Privacy Protection requires Limit IP Address Tracking to be enabled. To turn it on, go to Settings > Wi-Fi, tap next to your network, then enable Limit IP Address Tracking.

What this doesn't cover: Mail Privacy Protection does not extend to links or email attachments such as PDF or other files, according to Apple Support.

#How to block tracking pixels in Gmail

Setting Gmail to ask before displaying external images means images, including tracking pixels, don't load until you click Display images below.

#Steps to block images in Gmail

1. In the top right, click Settings, then See all settings
2. Scroll down to the "Images" section
3. Click Ask before displaying external images
4. At the bottom of the page, click Save Changes

When you receive a message with images, you'll see "Display images below" if you want to load them for that specific email.

How Gmail helps make images safe: According to Gmail Help, Gmail scans images for signs of suspicious content before you receive them. These scans make images safer because "Senders can't use image loading to get information about your computer or location. Senders can't use the image to set or read cookies in your browser."

Note: Gmail Help warns: "Sometimes, senders may know whether you've opened an email that has an image." If Gmail thinks a sender or message is suspicious, images aren't shown automatically.

#What blocking images doesn't fix

Blocking images stops tracking pixels from loading, but it doesn't stop other forms of tracking:

#Email tracking goes beyond pixels

The Princeton University study found that about 29% of emails in the study's corpus of commercial mailing-list emails leaked the address (viewed in a full email client). This happens through embedded content, not just pixels.

#Your email address is still out there

Blocking pixels hides your activity, but it doesn't remove your email address from data broker databases.

Type your name into a people-search site like TruePeopleSearch, Whitepages, or Spokeo, and there it is: your address, phone number, email addresses, and relatives. Anyone can look it up.

UndoLeak erases your data from data brokers and keeps it off, re-checking and erasing it again when it comes back.

Check your data free to see where you're exposed right now. The first scan is free.

#Other ways to limit email tracking

#1. Use plain text view

Most email clients offer a plain text view that strips out all HTML, including tracking pixels. The downside is you lose formatting, images you actually want to see, and embedded content.

#2. Use an email client with built-in blocking

Hey, according to the BBC, flags emails that contain spy pixels and blocks them. Other privacy-focused email clients offer similar features.

#3. Install browser extensions

If you use Gmail or another webmail service in a browser, extensions can strip out tracking pixels.

#4. Block all images by default

In most email clients, you can set images to not load by default. This is the most reliable way to block pixels, but it also blocks legitimate images.

#What the law says

The BBC's investigation noted that tracking pixels are governed in the UK and Europe by the Privacy and Electronic Communications Regulations (2003) and the General Data Protection Regulation (2016).

A privacy consultant told the BBC the Court of Justice of the European Union had previously ruled that such consent must be "unambiguous" and "a clear affirmative act." Pat Walshe of Privacy Matters added:

"Solely placing something in a privacy notice is not consent, and it is hardly transparent. The fact that tracking will take place and what that involves should be put in the user's face and involve them opting in."

Walshe added: "The law is clear enough, what we need is regulatory enforcement. Just because this practice is widespread doesn't mean it's correct and acceptable."

#Related guides

• How do spam callers know my name? - another way your personal information leaks
• Are apps selling your location? - location tracking beyond email
• How to remove your personal information from the internet - comprehensive removal guide
• What data brokers know about you - the full profile

#Sources

1. Leo Kelion, "'Spy pixels in emails have become endemic'", BBC News (February 17, 2021): bbc.com/news/technology-56071437 (accessed October 23, 2026)
2. Apple Support, "Use Mail Privacy Protection on iPhone": support.apple.com/guide/iphone/use-mail-privacy-protection-iphf084865c7/ios (accessed October 23, 2026)
3. Gmail Help, "Turn images on or off in Gmail": support.google.com/mail/answer/145919 (accessed October 23, 2026)
4. Steven Englehardt, Jeffrey Han, and Arvind Narayanan, "I never signed up for this! Privacy implications of email tracking", Proceedings on Privacy Enhancing Technologies 2018(1):109-126 (2018): petsymposium.org/popets/2018/popets-2018-0006.pdf (DOI: 10.1515/popets-2018-0006)

All email addresses, names, and example tracking scenarios shown in the video are fictional. All email client interfaces and tracking reports in the video are simplified recreations, not screenshots. This is general information, not legal advice.