An email size limit is a maximum message size that an email client or provider will reliably display or process. Size limits matter because large emails can be clipped, truncated, or slow to load. In practice, size constraints affect how you build templates, how many images you include, and how much inline CSS you generate.
Why Size Limits Affect Real Campaigns
Size limits often become visible through behavior like clipped email. If an email is clipped, recipients may not see your footer, legal text, or even key content. Gmail in particular is associated with size-based clipping, which is why Gmail rendering is part of most teams’ QA checklists. Size limits also affect deliverability indirectly, because very large emails can increase load time and create a poor user experience.
What Increases Email Size
The biggest contributors are excessive HTML structure, large embedded styles, and unoptimized images. Compiled templates and block-heavy systems can generate a lot of markup, especially when styles are fully inlined. That is why inline CSS is a tradeoff: it improves compatibility, but it can increase payload size. Images are another contributor, which is why image optimization matters. Optimize images, remove unused code, and avoid embedding large repeated chunks of HTML.
Practical Ways to Stay Under Limits
Keep templates modular and reuse known-good blocks. Remove unused classes and redundant markup. Compress images, avoid unnecessary tracking parameters, and use short link formats when possible. If you have long legal copy, consider whether it can be shortened without harming compliance, or whether a hosted page is acceptable. Track template size as a metric so you catch growth before it triggers clipping.
Email Size Limit and Topol
Topol helps teams keep templates maintainable and efficient by producing predictable output and reusable blocks, making it easier to control email size and reduce clipping risk. Learn more at Topol or sign up at Topol signup.