How many cold emails should I send per day?

Start with 5-10 per inbox per day for new accounts. After 2-3 weeks of warm-up, scale to 35-50 per inbox. If you need to send 500+ emails per day, use 10-15 warmed inboxes and rotate sends across all of them. Never push a single inbox beyond 50 cold emails per day.

What is a good cold email reply rate?

The average reply rate across all cold campaigns is 3.43%. A 'good' reply rate is 3-8%. Top performers consistently hit 8-15%. Rates above 15% are possible with excellent targeting and trigger-based personalization but are not typical at scale.

How long should a cold email be?

Keep cold emails between 50-125 words. Some studies suggest up to 150 words for certain B2B audiences. Shorter emails consistently outperform longer ones. If you need more than 125 words to make your point, your message is not focused enough.

Should I use HTML or plain text for cold emails?

Plain text. Always. HTML emails with logos, images, and formatted layouts trigger spam filters and look like marketing emails. A plain text email from one person to another is what cold email should look like. The only exception is your email signature, which can include basic formatting.

How many follow-ups should I send?

4-7 follow-ups is the sweet spot. 42% of replies come from follow-ups rather than the first email. Space them at Day 3, Day 7, Day 14, Day 21, and Day 30. Each follow-up should add new value, not just 'bump' the thread.

Cold Email Masterclass

Chapter 3 of 15

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Chapter 3

Cold Email Masterclass

Building Your Foundation

This chapter is not exciting.

It is the most important chapter in this entire cold email masterclass.

Deliverability Is Everything

Deliverability is the foundation of everything. If your emails do not reach the inbox, your copywriting skills, your personalization, and your follow-up sequences are worthless.

The global average inbox placement rate sits at 83.1%. That means roughly 17% of all emails never reach the primary inbox. For cold email specifically, that number is worse because cold senders face higher scrutiny from spam filters.

Here is what you need to set up before sending a single cold email.

Domain Authentication: SPF, DKIM, and DMARC

These three protocols prove to email providers that you are who you say you are. Without them, your emails look suspicious.

SPF (Sender Policy Framework)

SPF tells receiving servers which IP addresses can send email on behalf of your domain. Think of it as a guest list. If the sending server is not on the list, the email gets flagged.

How to set it up: Add a TXT record to your DNS that lists your authorized sending services.

v=spf1 include:_spf.google.com include:youremailservice.com ~all

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to each email you send. The receiving server checks this signature against a public key in your DNS. If the signature matches, the email passes verification.

How to set it up: Your email service provider generates a DKIM key pair. You add the public key as a TXT record in your DNS.

DMARC (Domain-based Message Authentication, Reporting, and Conformance)

DMARC ties SPF and DKIM together. It tells receiving servers what to do with emails that fail authentication checks.

How to set it up: Add a TXT record to your DNS.

v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com

2026 Standard

In 2026, setting your DMARC policy to p=reject is becoming the standard. This tells receiving servers to reject any email that fails SPF or DKIM checks. It protects your domain from spoofing and signals that you take authentication seriously.

Protocol Comparison

Protocol

What It Does

Impact on Deliverability

SPF

Authorizes sending servers

✓ Prevents spoofing from unauthorized IPs

DKIM

Signs emails cryptographically

✓ Proves email was not altered in transit

DMARC

Enforces SPF + DKIM policies

✓ Tells providers how to handle failures

No Auth

Nothing

✗ Emails land in spam or get rejected

Buying Secondary Domains

Never send cold email from your primary business domain. Never.

If your company is acme.com, buy domains like getacme.com, acmehq.com, tryacme.com, or acme.io for cold outreach. If a cold email domain gets blacklisted, your primary domain stays clean. Your marketing emails, transactional emails, and customer communications remain unaffected.

Buy 3-5 secondary domains. Set up separate Google Workspace or Microsoft 365 accounts on each. Authenticate SPF, DKIM, and DMARC on every single one.

Cost: roughly $12 per domain per year plus $6-$7 per inbox per month on Google Workspace. A small price compared to having your main domain flagged as spam.

Email Provider Selection

Google Workspace and Microsoft 365 are the two dominant choices for cold email.

Google WorkspaceHas the best deliverability for cold email in 2026. Google knows its own spam filters, and emails from Google Workspace tend to perform better in Gmail inboxes, which represent roughly 30% of business email.

Microsoft 365Works well for reaching Outlook and corporate inboxes. Many enterprise companies run on Microsoft infrastructure, and emails from Microsoft 365 accounts sometimes get preferential treatment in those environments.

Strategy

The smart move: use both. Set up inboxes on Google Workspace and Microsoft 365. Rotate between them to spread volume and reduce risk.

Inbox Limits and Safe Sending

Each inbox has a safe daily sending limit for cold email:

Phase

Cold Email Sends

Time Period

New inboxes

5-10 emails per day

First 2 weeks

Warming phase

15-25 emails per day

Weeks 2-4

Fully warmed

35-50 emails per day maximum

Month 2+

These numbers feel low. That is the point. Cold email in 2026 is a precision game, not a volume game.

If you need to send 500 emails per day, you need 10-15 warmed inboxes. Not one inbox pushing 500 sends.

Firstsales.io Advantage

Tools like Firstsales.io let you connect unlimited email accounts and rotate sends automatically. This spreads volume across inboxes so no single account gets flagged for unusual activity.

Key Takeaway

Deliverability is the foundation. Skip authentication and proper setup, and nothing else matters. Set up SPF, DKIM, and DMARC. Use secondary domains. Respect inbox limits. Your future self will thank you.

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Related Masterclass Chapters

Explore more chapters from the Cold Email Masterclass.

Chapter 1

Why Cold Email Still Works in 2026

8 min

Chapter 2

The Cold Email Mindset Shift

7 min

Chapter 4

Inbox Warm-Up Strategy

7 min

Chapter 5

List Building & Research

9 min

Chapter 6

Writing Cold Emails That Get Replies

8 min

Chapter 7

Personalization at Scale

7 min

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