Definition
Capped frequency, also called frequency capping, sets a maximum number of emails a subscriber can receive within a defined period — typically per day, per week, or per month. This prevents a subscriber who qualifies for multiple campaigns from receiving too many emails in a short timeframe.
Frequency capping is distinct from setting a global send cadence (e.g., "we send weekly"). Capping applies per subscriber regardless of how many active campaigns they are eligible for. Without capping, a subscriber in multiple segments could receive 10+ emails in a day, leading to fatigue, unsubscribes, and spam complaints.
Frequency Capping Strategies
| Cap Type | Period | Example |
|---|---|---|
| Daily cap | Per 24 hours | Max 1 email per day |
| Weekly cap | Per 7 days | Max 3 emails per week |
| Monthly cap | Per 30 days | Max 8 emails per month |
| Rolling cap | Sliding window | Max 5 emails in any 7-day period |
| Per-campaign cap | Per campaign series | Max 1 email per campaign per day |
Best Practices
- Set conservative caps initially and relax based on engagement data
- Allow priority campaigns (transactional, time-sensitive) to bypass caps
- Communicate cap policies to stakeholders who request additional sends
- Monitor how often subscribers hit caps to understand if your cadence is too aggressive
- Use engagement-tiered capping — active subscribers may tolerate higher caps
- Ensure capping logic accounts for automation flows, not just broadcast campaigns
- Test cap limits with A/B experiments to find the optimal balance
Related Glossary Terms
Email Cadence
Email cadence is the frequency and pattern of your email sends — how often subscribers hear from you and the rhythm that balances engagement with fatigue to maintain a healthy email programme.
Email Fatigue
Email fatigue occurs when subscribers become overwhelmed by email volume or repetitive content, leading to declining engagement, increased unsubscribes, and higher spam complaints.
Frequency Cap Management
Frequency cap management controls how often emails are sent to individual subscribers, balancing engagement with inbox presence to avoid fatigue and unsubscribes.
Email Send Frequency
Email send frequency refers to how often a sender delivers campaigns to subscribers, balancing engagement maximisation against unsubscribe and fatigue risks.
Frequently Asked Questions
A common starting point is 1 email per day and 5 per week. This accommodates most campaign schedules without over-messaging. Adjust based on your specific audience, content quality, and industry — high-value daily content can support higher caps; promotional content may need lower caps.
Transactional emails (order confirmations, password resets, shipping notifications) should typically bypass frequency caps because the recipient expects and needs them. Caps should apply only to marketing and promotional emails. Your ESP should allow configuring which email types are subject to capping.