Newsletter Growth Calculator
Project email newsletter subscriber growth over 6, 12, and 24 months.
Enter list size, monthly growth rate, and churn to forecast your total subscriber count.
Newsletter subscriber growth rate tracks how quickly your email list is expanding and projects future size based on current trends.
The core formulas:
Monthly Growth Rate = ((New Subscribers − Unsubscribes) / Starting Subscribers) × 100
Net New Subscribers = New Sign-ups − Unsubscribes − Hard Bounces
Projected Size = Current Size × (1 + Monthly Growth Rate)^Months
Months to Double = 70 / Monthly Growth Rate (Rule of 70 approximation)
What each variable means:
- New Subscribers — people who opted in during the period
- Unsubscribes — people who opted out (healthy churn: under 0.5% per send)
- Hard Bounces — invalid email addresses that should be removed permanently
- Monthly Growth Rate — net percentage increase month-over-month
Worked example: You start January with 5,000 subscribers. You gain 320 new subscribers and lose 80 unsubscribes.
Net new = 320 − 80 = 240 Monthly growth rate = (240 / 5,000) × 100 = 4.8%/month Projected size in 12 months = 5,000 × (1.048)^12 = 5,000 × 1.757 = 8,785 subscribers Months to double = 70 / 4.8 ≈ 14.6 months
Healthy benchmarks:
- Good monthly growth rate: 3–8%
- Unsubscribe rate per send: under 0.5%
- Open rate: above 25%
- Click-to-open rate (CTOR): above 10%
To accelerate growth: add a content upgrade (lead magnet) to your top blog posts, run a referral program, or partner with complementary newsletters for cross-promotions.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.