Summary
Experts and email marketers almost universally recommend a gradual and monitored approach to increasing email volume when sending from SFMC. There's no single 'safe' percentage; instead, the acceptable increase depends on various factors. During IP warming, some experts suggest increases up to 50% per day, while others recommend capping weekly increases around 25% or doubling volume every few days, if metrics are good. Across all sources, a core theme is the importance of starting with highly engaged recipients, closely monitoring engagement and deliverability metrics (bounce rates, spam complaints), and dynamically adjusting the sending strategy based on the results. List quality, sender reputation, and infrastructure capacity all significantly influence how rapidly volume can be safely increased.
Key findings
- Gradual Ramp-Up is Key: Almost all sources emphasize the importance of a gradual, controlled increase in email volume.
- Engagement Matters Most: Prioritize sending to engaged recipients first and monitoring their interaction to ensure positive sender reputation.
- Monitor Deliverability Metrics: Continuous monitoring of bounce rates, spam complaints, and deliverability is crucial to detect and address issues early.
- Percentage Varies Widely: The safe percentage increase ranges considerably based on several factors; there's no one-size-fits-all rule.
- Spikey Volume Impact: Spreading spikey volume can help manage deliverability
Key considerations
- Sender Reputation: Evaluate your current sender reputation before increasing volume.
- List Quality: Ensure your email list is clean, up-to-date, and composed of engaged subscribers.
- Infrastructure Capacity: Confirm your infrastructure can handle the increased volume without affecting deliverability.
- IP Warming: If warming up new IPs, follow a structured IP warming strategy with very gradual increases.
- Metric Response: Be ready to adapt your sending strategy according to the deliverability metrics.
- Authentication: Ensure authentication is setup correctly.
What email marketers say
10 marketer opinions
Experts and marketers generally recommend a gradual approach to increasing email volume from SFMC. The specific safe percentage varies depending on factors like sender reputation, list quality, and engagement. Recommendations range from doubling volume every few days (while closely monitoring metrics) to increasing by no more than 10-50% at a time or 25% per week during ramp-up. Starting with highly engaged subscribers and closely watching deliverability metrics are consistently emphasized.
Key opinions
- Gradual Increase: A gradual increase in email volume is crucial for maintaining deliverability.
- Engagement Focus: Start with sending to your most engaged subscribers to build a positive reputation.
- Metric Monitoring: Closely monitor key metrics like bounce rates, spam complaints, and engagement to adjust your strategy.
- Variable Percentages: Safe percentage increases vary widely (10-50%), depending on factors like sender reputation and list quality.
Key considerations
- Sender Reputation: Your existing sender reputation significantly impacts how aggressively you can increase volume.
- List Quality: The quality of your email list (e.g., opt-in practices, hygiene) influences deliverability and volume increases.
- Infrastructure: Your email infrastructure (e.g., dedicated IPs, authentication) affects your ability to scale sending.
- Deliverability Metrics: Regularly assess metrics and adjust ramp-up to improve deliverability.
Marketer view
Email marketer from Mailjet answers that the strategy for increasing volume should be based on sender reputation, list quality, and the infrastructure, and recommends following a gradual approach of warming IP addresses, increasing volume slowly, and monitoring metrics for at least the first few weeks.
14 Jun 2022 - Mailjet
Marketer view
Email marketer from GlockApps recommends starting with low volumes (hundreds) and doubling the volume every 2-3 days, monitoring placement carefully. They advise checking seed lists, engaging with postmaster tools, and using authentication properly to ensure a successful volume ramp.
21 Jun 2022 - GlockApps
What the experts say
4 expert opinions
Experts suggest that there is no one-size-fits-all answer to the question of safe email volume increase percentages. While some recommend specific percentages (up to 50% per day when warming up), the overarching theme is to prioritize monitoring recipient engagement and deliverability metrics. Factors such as list quality and proactive management of bounces, spam complaints, and blocklistings are deemed critical for sustainable deliverability when scaling email volume, and spreading out spikes over multiple days can help.
Key opinions
- Metrics over Percentages: Monitoring recipient engagement and deliverability metrics is more important than adhering to a specific percentage increase.
- IP Warming Context: Higher percentage increases (e.g., 50% per day) are sometimes acceptable during IP warming, where careful monitoring is essential.
- List Quality Matters: The quality of the email list directly impacts the safe percentage increase.
- Spikey Volume Impact: Spreading spikey volume can help manage deliverability
Key considerations
- Recipient Engagement: Actively monitor opens, clicks, and conversions to gauge recipient engagement.
- Deliverability Metrics: Track bounce rates, spam complaints, and blocklistings to identify potential issues.
- Proactive Management: Implement strategies for managing bounces, spam complaints, and blocklistings.
- Context of Increase: Determine whether you're warming an IP or scaling existing sends, as this informs the percentage increase.
Expert view
Expert from Email Geeks explains that spreading spikey volume over a few days can help manage deliverability.
1 May 2022 - Email Geeks
Expert view
Expert from SpamResource explains that warming IP addresses is essential for high email volume, recommending a strategy of progressive volume increases and careful monitoring of bounces, spam complaints, and blocklistings. They didn't recommend a specific percentage, instead focusing on monitoring key metrics.
2 Jan 2024 - SpamResource
What the documentation says
4 technical articles
Email marketing documentation emphasizes a gradual ramp-up in email volume when sending from SFMC. Key recommendations include starting with a small number of emails to engaged recipients, consistently increasing volume over time, and actively monitoring engagement metrics (bounce rates, spam complaints) to adjust strategy and maintain deliverability. Sender reputation and infrastructure play a crucial role in how quickly volume can be safely increased.
Key findings
- Gradual Ramp-Up: A consistent, gradual increase is crucial for maintaining email deliverability.
- Engaged Recipients First: Begin by sending to your most engaged recipients before expanding to the broader list.
- Monitor Key Metrics: Continuously monitor metrics such as bounce rates and engagement to assess the impact of volume increases.
Key considerations
- Sender Reputation: Consider your current sender reputation when determining the rate of volume increase.
- Infrastructure Capacity: Ensure your infrastructure can handle increased volume without impacting deliverability.
- Strategic Adjustments: Be prepared to adjust your strategy based on ongoing monitoring and feedback.
- IP warming: Warming up IP addresses is a critical consideration
Technical article
Documentation from Twilio SendGrid emphasises a gradual ramp-up when increasing email volume. They recommend starting with a small number of emails and slowly increasing the volume over time while closely monitoring engagement metrics and deliverability.
25 Dec 2023 - Twilio SendGrid
Technical article
Documentation from SparkPost explains that when ramping up email volume, it is important to increase gradually and consistently. A good approach is to start with your most engaged recipients and monitor your deliverability metrics.
25 May 2025 - SparkPost
Do I need an IP warm-up when moving to a new ESP with shared IPs?
Do I need to warm up my email list of 100k contacts?
Does send time impact IP warmup and reputation when using a new ESP?
How do email volume and volume fluctuations affect deliverability and sender reputation?
How do I warm up a new IP address for transactional emails?
How do I warm up new IP addresses for email sending?
