What is the recommended daily sending limit for an IP address?

Summary

The consensus from experts and marketers is that there isn't a one-size-fits-all recommended daily sending limit for an IP address. Deliverability depends on multiple factors, primarily focusing on IP reputation, engagement, and following the guidelines of your ESP and recipient mailbox providers. Warming up new IPs gradually with smaller volumes, sending consistent amounts of email, and ensuring the mail is wanted by engaged users are essential. Sudden spikes should be avoided as they can negatively impact your reputation. Furthermore, some ESPs adjust sending limits dynamically based on your sending history and reputation.

Key findings

  • No universal limit: There's no single recommended daily sending limit that applies to everyone.
  • Reputation is paramount: Maintaining a good IP and domain reputation is crucial for deliverability.
  • IP warming is essential: Gradual IP warmup is crucial for new IP addresses to establish a positive reputation.
  • Engagement over quantity: Focus on sending wanted mail to engaged users, rather than just maximizing sending volume.
  • ESP Dependent: Sending limits and best practices depend on your ESP's policies and capabilities.

Key considerations

  • Start small: Begin with small sending volumes, especially for new IPs.
  • Consistent sending: Maintain consistent sending volumes to establish a reliable reputation.
  • Engaged subscribers: Send primarily to engaged subscribers to improve your sender reputation.
  • Avoid spikes: Avoid sudden increases in sending volume, which can negatively impact deliverability.
  • Monitor performance: Monitor your sending performance (bounces, complaints, engagement) and adjust your strategy accordingly.
  • Consult your ESP: Work with your ESP to understand their recommended sending limits and best practices.

What email marketers say
13Marketer opinions

There is no single recommended daily sending limit for an IP address. Instead, it's a multifaceted issue influenced by several factors, including the recipient mailbox provider's profiling methods, the sender's IP and domain reputation, engagement levels, and the specific policies of the Email Service Provider (ESP) used. Warming up new IPs gradually with smaller volumes and consistent sending habits is crucial. Focusing on list hygiene, relevant content, and positive engagement metrics is more important than adhering to a fixed number. Monitoring bounces and spam complaints, coupled with adapting sending rates based on feedback, is vital for maintaining a healthy sending reputation and deliverability.

Key opinions

  • No Hard Limit: There isn't a universal hard limit on daily sending volume. It's variable and dependent on multiple factors.
  • IP Reputation Matters: A good IP and domain reputation is crucial for deliverability. Sending wanted mail to engaged users is key to building up good reputation.
  • ESP Policies: ESPs have their own technical limitations and recommendations that can affect sending volumes.
  • Warming Up: New IP addresses need to be warmed up gradually to build a positive sending reputation.
  • Engagement is Key: Engagement metrics (open rates, click rates) are more important than the specific number of emails sent.

Key considerations

  • Recipient Profiling: Understand that recipient mailbox providers have methods to profile traffic, including throttling new IPs.
  • Migration Plans: If migrating ESPs with high volumes, ensure the migration plan addresses IP considerations.
  • List Hygiene: Maintain a clean email list to improve engagement and avoid deliverability issues.
  • Consistent Sending: Focus on consistent sending habits, avoiding sudden spikes in volume.
  • Monitor Feedback: Monitor bounces, spam complaints, and engagement metrics to adjust sending rates appropriately.
  • Segmentation: Segment your best contacts first, as those are more likely to be engaged.
Marketer view

Email marketer from Reddit shares that it's less about a hard limit and more about engagement. Focus on list hygiene and sending relevant content. If your open/click rates are good, you can send more without issues.

December 2021 - Reddit
Marketer view

Marketer from Email Geeks explains that every recipient mailbox provider has their own methods for profiling traffic and some use throttling on new IPs. States that your ESP should have intelligence built in so you shouldn't have to worry.

February 2022 - Email Geeks

What the experts say
3Expert opinions

While some suggest a second IP address at a million sends per day, it's not a strict limit. Maintaining a strong sender reputation by sending only wanted mail to engaged readers is critical. New IPs should start with small volumes and gradually warm up, sending consistent numbers of emails daily to build trust over time.

Key opinions

  • No Strict Limit: While some suggest a second IP at 1 million, some send far more from one IP.
  • Reputation is Key: Your sending reputation is linked to your IP and domain.
  • Warming Up is Essential: Gradual IP warmup builds trust and ensures deliverability.

Key considerations

  • Wanted Mail Only: Send only to engaged readers to protect your reputation.
  • Start Small: Begin with small volumes on new IPs.
  • Consistency: Maintain consistent sending volumes over time for IP warmup.
Expert view

Expert from Email Geeks shares that at a million sends a day it's a good idea to get a second IP, but mentions a client sending 20 million a day from a single IP.

September 2022 - Email Geeks
Expert view

Expert from Spam Resource explains that your sending reputation is linked to your IP and domain so you need to protect this by only sending wanted mail. Start new IPs out small and make sure that they are delivered to engaged readers

August 2022 - Spam Resource

What the documentation says
5Technical articles

There isn't a universally defined daily sending limit for an IP address. Maintaining a good IP reputation is crucial for deliverability, and sudden spikes in sending volume can negatively impact it. Email Service Providers (ESPs) like Amazon SES and Microsoft dynamically adjust sending limits based on sender reputation and sending history. Gradual IP warmup with smaller volumes, increasing incrementally over time, is advised. SMTP servers can impose rate limits to prevent abuse, even though there are no globally defined daily limits.

Key findings

  • Reputation Focus: Maintaining a good IP reputation is crucial for deliverability.
  • No Global Limit: No specific global daily limits are defined for IP addresses.
  • Dynamic Limits: ESPs dynamically adjust sending limits based on sender reputation and history.
  • Warmup Advised: Gradual IP warmup is advised to build a positive sending reputation.
  • Rate Limiting: SMTP servers can impose rate limits to prevent abuse.

Key considerations

  • Consistent Volume: Maintain consistent sending volumes to establish a reputation.
  • Avoid Spikes: Avoid sudden spikes in sending volume to prevent negative impacts on reputation.
  • Incremental Increase: Incrementally increase sending volume over time during IP warmup.
  • List Size and Engagement: Consider list size and engagement when determining sending volume.
  • Sending History: Recognize that sending limits increase as you build a positive sending history.
Technical article

Documentation from SparkPost emphasizes a gradual IP warmup to build a positive sending reputation. Starting with smaller volumes and increasing it incrementally over weeks is advised. Volume depends on list size and engagement.

October 2022 - SparkPost
Technical article

Documentation from Google Postmaster Tools Help explains that maintaining a good IP reputation is crucial. Volume of email doesn't directly impact reputation, but sudden spikes can affect it. They recommend consistent sending volumes to establish a reputation.

January 2022 - Google Postmaster Tools Help