What’s the max recommended total weight for an email?

Gmail clips any email message whose HTML payload exceeds roughly 102KB. When that happens, subscribers see a grey bar at the bottom that says "Message clipped [View entire message]" and your footer disappears, which means your unsubscribe link and your CAN-SPAM-required physical address are gone. That's not a deliverability theory; it's a specific inbox behavior that affects every sender whose templates run heavy.

The 102KB figure applies to the HTML source of your email, not to images. Images load separately from external URLs and don't count against this limit as long as they're hosted externally and referenced by a standard src attribute. What does count: all your HTML tags, inline CSS, text content, and anything else in the source file itself. The practical target most ESPs recommend is to keep your HTML under 100KB, which gives you a small buffer below the threshold and leaves room for personalization tokens to expand on render.

The most common causes of HTML bloat are deeply nested tables (legacy email layout adds tag overhead fast), inline styles repeated on every element instead of using a shared CSS block, preheader text tricks using long strings of invisible whitespace characters, and base64-encoded images embedded directly in the HTML rather than linked from a CDN. HTML minification strips comments and unnecessary whitespace and can cut file size by 10 to 20 percent. Mailchimp and Klaviyo both do some minification automatically on send, but it's worth checking your starting weight before you rely on it. The guide on base64 encoding covers one of the highest-impact size fixes in detail.

For your total message size, the informal industry guideline is under 600KB for the full MIME package including the HTML part, plain-text fallback, and any attachments. Image file sizes don't count toward the HTML limit, but they still affect how quickly your email renders on mobile connections. Keep individual images under 200KB where you can, and aim for a combined image payload that would load acceptably on a modest cellular connection. To check where you stand, paste your template HTML into any file size calculator or inspect the source in your ESP's preview pane. If you're near the 100KB line, start with duplicated inline styles and unnecessary table nesting. Those two changes typically cut 20 to 30 percent off template weight without touching a single word of copy.