What Is The Maximum Value That You Can Send Register Mail

Every electronic mail sending provider has its own maximum electronic mail size limit. However, there is no unique standard – limits are dictated mostly by operation and security reasons. There are many things you should proceed in mind when preparing your email notifications or newsletters: from the maximum size of file attachments and HTML role to the email client your recipients will well-nigh likely utilize. Also, there are some not so obvious factors, which impact the actual email size and deliverability. In this article, nosotros have gathered replies to the most common related questions:

What is the recommended size for the electronic mail body and attachments?
What are the limits of different email clients and sending providers?
How do the embedded images affect email size, spam score, and deliverability?
What are the mutual issues and errors related to email size and how to handle them?

Also, we have implemented an email size limit for Mailtrap: let'south review how information technology works and how it tin assistance you with testing your email deliverability.

Types of email size limits

Email size limits are used for three main reasons:

Performance. E-mail systems are non designed to transfer large volumes of information. They deal with SMTP, which is a quite outdated protocol. Near of the systems are not able to process multiple information sources at one time. In addition, postal service transfer agents often scan incoming information for viruses and other potential risks, which also takes resources and affects system functioning.
Database/storage size. Electronic mail data should exist stored on a server (either cloud or local). This is why non only the bulletin itself but also the inbox as a whole has its own limits.
Security. Points ane and 2 on our listing likewise lead to potential security vulnerabilities. Electronic mail systems ordinarily use a limited number of ports to retrieve data. This makes them candidates for DoS (denial of service) attacks: a huge amount of large messages can take the whole system down. This is also known equally an email flop.

When preparing either transactional or marketing emails, you lot should consider ii limits:

limit to ship a message (your electronic mail organization)
limit to recall a message (your recipients' post system).

For case, if your e-mail service is able to send messages up to 15 MB but the e-mail recipient can retrieve letters merely up to 10 MB, it'southward obvious that your email should not exceed 10MB. Otherwise, the email will be rejected. It is useful to know the allowance for your recipient's incoming messages.

If you work with a big database of email addresses to transport transactional or marketing emails and don't accept such details well-nigh your recipients, yous should follow a general rule: ship messages that don't exceed 10 MB.

Limits for popular email sending providers and clients like Gmail, Outlook, Sendgrid, etc.

E-mail client	Sending and inbound size limits
AOL	25 MB
Apple tree Mail (iCloud)	xx MB
Gmail	25 MB
GMX	fifty MB
Outlook/Office 365	20 MB (x MB for Exchange accounts), with upwardly to 150 MB in Office 365
ProtonMail	25 MB
Thunderbird	no
Yahoo	25 MB
Zoho Mail	20 MB

Email clients size limits

Email sending provider	Sending size limit	Special notes
AWS SES	10 MB
Mailgun	25 MB
Mandrill	25 MB
Postmark	10 MB	TextBody and HtmlBody can each be up to 5 MB each
Sendgrid	30 MB

ESPs size limits

Y'all can see that most email clients are capable of retrieving twenty – 25 MB of email information. Information technology'southward a pretty rare situation when y'all need to send a mass email with large attachments. Just it is still possible when you send numerous booking or order confirmations, for example. However, besides general deliverability, there are few more concerns related to sending large messages. Spam score and rendering bug are the most important. Moreover, some ESPs like Postmark accept additional limits for the email torso size.

What else should you consider near the size of your e-mail?

Taking care to create a message that will be successfully delivered to your recipients, you should besides remember of which folder information technology will go to, how quickly information technology volition be delivered, and how happy your recipients volition be.

Inspect Your Emails

Spam score

Avoiding spam filters and targeting the main folder of your recipient'due south inbox is ane of the trickiest things in email handling. You won't observe strict and ubiquitous criteria for spam detection. However, there is a list of mutual "anti-spam" rules, and the size-related points are at the top of it.

Technically, there is no message body limit in the SMTP protocol. Notwithstanding, some providers accept their ain limits. For instance, Postmark allows the HTML and text parts each to exist v MB, while Gmail clips the body of letters over 102 KB.

Many tests by various providers prove the correlation between electronic mail size and deliverability. In nigh cases, messages with a body over 100 – 150 KB trigger spam filters. Then, the common recommendation is to continue email torso size between 15 KB and 100 KB.

Rendering bug

Another attribute of large emails is their loading and/or rendering speed. Your recipients do not always take access to a high-speed connection, and a long-lasting message loading process might crusade irritation. In improver, in many email clients, a big electronic mail torso might be rendered merely partially, and your recipient will see but parts of images or clipped content. This might strongly harm your customer digital experience and leave a bad general impression.

Notwithstanding the numerous limitations and hidden constraints, there are mutual rules on building well-performing emails. The first of these is to subtract and optimize email body size.

What does affect the email size and how tin you optimize it?

Each element of the message and the way information technology's implemented impacts email size.

Attachments. With attachments everything is straightforward. These are enclosed files and don't bear on the e-mail trunk size. The total email limit normally includes all of the attachments. The best option is to upload files you lot need to transfer to the cloud and put a link into your bulletin. Due to security issues, many file types are blocked or are considered dangerous (including .doc, .xls, and .pdf).
Images and other embedded elements. Even simple notifications ordinarily contain images, at least your company logo. Their size depends on the image format and the way the paradigm is embedded into the bulletin. We had a closer look at this topic in this article. In short, wherever possible, link to an image hosted on an external server (in the HTML, so information technology volition exist displayed as function of the message).
Encoding. MIME-encoded (base64) letters add 33% to your email size. Keep this in mind when coding a multipart message.
Other. Every single message element affects its general size. Bulletin headers, signatures, formatting – all of these add extra kilobytes.

Rules of a perfect email

Considering the above mentioned limits and dependencies, nosotros have created a short e-mail size optimization checklist. Here are the all-time practices for building a well-performing email in terms of size:

Keep the email torso from 15 KB to 100 KB.
Don't add attachments over 10 MB. If possible – upload your files to the external server and make them bachelor online/ for download using a link.
Don't overuse images, GIFs, and other multimedia content.
Recall that most 42% of emails are opened on mobile devices. Keep this in heed when creating electronic mail templates. They should be responsive. Using a responsive email framework or an e-mail builder tin can save you fretfulness and kilobytes.

Check email size in Mailtrap before sending

Even if you followed all recommendations and take crafted the perfect message, checking its size is not an easy task. Whether yous are coding a bulletin in your app or preparing a template to send via Gmail, yous demand to use a third-political party tool, actually send your bulletin, or download information technology then to explore its size.

If y'all use Mailtrap for testing your emails before sending them to your real recipients, you can easily cheque both the e-mail torso and attachment size.

check email body and attachment size in Mailtrap

Every bit soon as your test message is trapped in your virtual inbox, the total email size is displayed forth with the bulletin headers. If your bulletin has attachments, you will see a list of them with file names and sizes.

Also, Mailtrap has electronic mail size limits, which depend on your billing programme. You tin can examination messages upwardly to 5 MB (total e-mail size with attachments) for free. The maximum possible email size to exam is limited to 25 MB.

Instead of offering a determination, let's review the most common SMTP errors related to the mail service size. There are two of them:

Mistake code	Description	Reason and how to solve
Mistake 523	The Recipient'due south mailbox cannot receive letters this big.	Your message exceeds the size limit of your recipient'south server. Check the size of the email body and attachments. Use the recommendations above to optimize it.
Error 552	Requested mail action aborted: exceeded storage allocation or size of the incoming bulletin exceeds the incoming size limit.	The e-mail box of your recipient is full. In this case you have naught to exercise: your recipient should clean upwards his or her inbox.Or your message exceeds the limit ready by the administrator. Check the size of your message and optimize it.

SMTP codes will be completed with additional numbers and letters so y'all will be able to sympathize the exact reason. The general rule is to proceed your electronic mail size as compact as possible, check, and test it before sending to real recipients.