Email is still the highest-ROI channel in marketing — but only when the copy works. Subject lines decide opens, preview text decides hesitation, body decides intent, and CTAs decide revenue. Each piece is a separate craft, and ignoring any one of them undercuts the rest.
Email Copy Component Lengths
| Component | Ideal Length | Purpose |
|---|---|---|
| Subject line | 30-50 chars | Earn the open |
| Preview text | 50-90 chars | Reinforce, intrigue |
| Opening sentence | Under 12 words | Keep them reading |
| Body (promo) | 50-125 words | One idea, one ask |
| Primary CTA | 2-5 words | Get the click |
Subject & Preview
Treat them as a pair. The subject is a question or hook; the preview is the down payment on the answer. Avoid restating the subject — that wastes the second hook. Strong combinations: "Your June numbers" / "Three insights inside (avg. read: 2 min)."
Body Structure
- Opening — context in one sentence. No "Hope you're doing well."
- Value — the offer, story, or insight. Lead with the benefit.
- Proof — a number, name, or quote when relevant.
- CTA — one clear action, button-styled if possible.
- PS line — second-most-read line; reinforce urgency or add a bonus.
CTAs That Convert
Use specific verbs and first-person framing where appropriate. "Start my free trial" outperforms "Start free trial" because it primes ownership. Keep CTAs benefit-led: "Get my discount" beats "Submit." Place the primary CTA above the fold and repeat once more before the signature.
Test Your Subject Lines
Score subject lines for length, sentiment, spam triggers, and emoji impact.
Email Subject Tester →