Cold Email Strategy February 2026 7 min read

How Many Cold Emails Should You Send Per Day?

The answer is not "as many as possible." Sending volume is a balance between reaching enough people and maintaining the deliverability that makes those emails actually arrive.

This is one of the most common questions we hear from businesses considering cold email, and the answer they expect is almost always wrong. They expect a single number. What they need is an understanding of why the number matters, how it connects to infrastructure, and what happens when you get it wrong.

So let us break it down properly.

The Per-Inbox Limit

The first thing to understand is that cold email volume is measured per inbox, not per campaign, not per domain, and not per day overall.

Each individual inbox -- each separate email account you send from -- should send a maximum of 15 emails per day, ramped up gradually over time.

You start at 5 to 7, then increase through 7 to 10, 10 to 12, and eventually up to 12 to 15. That ramp-up is non-negotiable.

Why not more?

Email providers like Google and Microsoft monitor sending behaviour at the inbox level. When an inbox sends 30, 40, or 50 emails in a day, it triggers automated scrutiny. Normal business professionals do not send 50 emails per day to people they have never corresponded with. Spam operations do.

The moment an inbox gets flagged for unusual sending patterns, several things happen simultaneously:

Keeping each inbox at 15 or below keeps you well within the bounds of what email providers consider normal behaviour. It is conservative by design, because the cost of being flagged far outweighs the benefit of sending a few extra emails per day.

Why not fewer?

Sending fewer than 5 per inbox per day is technically safe for deliverability. The problem is economics. If each inbox only sends 3 emails per day, you need far more inboxes to reach the same volume. That means higher costs for domains, inbox licences, warmup, and management.

The ramp-up to 15 hits the sweet spot: high enough to justify the cost of each inbox, low enough to maintain deliverability.

The Maths Behind Campaign Volume

Here is where it gets practical. Let us work through the numbers for a typical campaign using 100 inboxes.

Daily volume

100 inboxes x 10 emails per inbox = 1,000 emails per day

We use 10 as the average rather than the maximum of 15. This accounts for the fact that some inboxes will still be ramping up while others are at full volume, and some may be temporarily paused for warmup maintenance or rotation.

Weekly volume

1,000 emails per day x 5 sending days = 5,000 emails per week

We send on weekdays only. More on that later.

Monthly volume

5,000 per week x 4 weeks = 20,000 to 25,000 emails per month

The range accounts for months with different numbers of working days and for occasional pauses due to public holidays or infrastructure maintenance.

But that is not 16,000 unique prospects

This is where many people make a mistake. If your campaign uses a multi-step sequence -- and it should -- each prospect receives more than one email.

A typical cold email sequence has 3 steps:

That means each prospect receives up to 3 emails. So your 20,000 to 25,000 monthly sends actually reach approximately 6,500 to 8,500 unique prospects.

Some agencies use longer sequences of 4 or 5 steps. We generally recommend 3. Beyond 3 follow-ups, the marginal return drops significantly, and the risk of being marked as spam by recipients increases.

What does that translate to in results?

Here is where volume connects to pipeline. These numbers assume properly built lists, well-written copy, and solid infrastructure:

A 2 to 3% overall reply rate is realistic for a well-executed B2B cold email campaign. Of those replies, roughly 30 to 50% will be positive -- meaning the prospect is interested in a conversation, not just replying to say "not interested" or "remove me."

That gives you 35 to 115 qualified conversations per month from 100 inboxes. At Sparklead, we run 120 to 125 inboxes per client, which pushes those numbers slightly higher.

The question to ask yourself is: how many qualified conversations per month does your sales team need to hit target? Work backwards from there to determine your required volume.

Why More Volume Is Not Always Better

The instinct for most businesses is straightforward: if 100 inboxes generate 50 conversations, then 200 inboxes should generate 100. Just double everything.

In theory, yes. In practice, it is not that simple.

Diminishing returns on list quality

The more prospects you need to contact per month, the deeper you have to go into your addressable market. The first 5,000 prospects you pull are usually the closest match to your ideal customer profile. The next 5,000 are slightly less relevant. By the time you are pulling 15,000 to 20,000 unique prospects per month, you are often contacting people who are a marginal fit at best.

Marginal fit means lower reply rates, which means lower positive reply rates, which means fewer qualified conversations per email sent. Your cost per conversation goes up even as your total volume goes up.

Deliverability risk compounds

More inboxes means more domains. More domains means more DNS records to manage, more warmup to maintain, more monitoring to do. The operational complexity increases faster than the volume.

A single misconfigured domain can affect deliverability across your entire sending infrastructure if it shares IP ranges with other domains. At higher volumes, the probability of something going wrong increases, and the blast radius of mistakes grows.

Reply management becomes a bottleneck

This is the one nobody thinks about until it hits them. If you are generating 150 to 200 replies per month, someone needs to read, categorise, and respond to every single one of them within a reasonable timeframe.

Positive replies need to be routed to sales. Negative replies need to be handled professionally. Out-of-office replies need to be noted for follow-up. "Not interested" replies need to be removed from future sequences.

If your reply management is slow or sloppy, you lose the prospects who were genuinely interested. They replied at a moment of relevance. If you take 48 hours to respond, that moment has passed.

Quality over quantity

The better approach is to optimise what you already have before scaling volume:

Scale volume after you have maximised the return on your existing infrastructure. Not before.

How to Scale Volume Safely

When you have optimised your current setup and genuinely need more volume, here is how to scale without destroying your deliverability.

Add inboxes gradually

Do not add 50 new inboxes in a single day and start sending from all of them. Add 10 to 15 at a time. Let each batch warm up for the full 14 to 21 days before adding the next batch.

This gradual approach lets you monitor deliverability at each stage and catch problems before they affect your entire infrastructure.

Warm every single inbox

No exceptions. Every new inbox goes through the full warmup process before sending a single outreach email. The temptation to skip warmup when you are eager to scale is strong. Resist it. The short-term delay saves you from the long-term cost of burned domains.

Monitor your metrics continuously

The key metrics to watch when scaling:

Scale back immediately if metrics decline

If your bounce rate climbs above 3%, pause sending from the affected inboxes. If reply rates drop significantly across multiple inboxes, investigate before adding any more volume. If spam complaints appear, stop and diagnose the cause.

Scaling is not a one-way process. You need to be willing to reduce volume as quickly as you increased it if the data tells you something is wrong.

Rotate domains and inboxes

No domain or inbox should run indefinitely without rest. We rotate inboxes regularly, retiring ones that have been sending for several months and replacing them with freshly warmed alternatives. This keeps the overall infrastructure healthy and prevents reputation decay.

Weekend Sending and Timing

Should you send on weekends?

No. Send on weekdays only, Monday through Friday.

The reason is simple: business professionals check their email during business hours. An email that arrives at 9am on a Tuesday sits in the inbox when the recipient opens their laptop. An email that arrives at 2pm on a Saturday gets buried under Monday morning's avalanche of messages.

More importantly, weekend sending is a spam signal. Legitimate business communication happens during business hours. Spam operations run 24/7. Email providers know this, and weekend sending from a cold email inbox raises flags.

What time of day?

Send during business hours in the recipient's timezone. Not your timezone -- theirs. If you are targeting prospects in the UK, send between 8am and 5pm GMT. If you are targeting US East Coast, send between 8am and 5pm EST.

The best windows are generally:

Avoid sending all your daily emails at the same time. Spread them throughout the day. A burst of 8 emails all sent at exactly 9:00am looks automated (because it is). Emails spread between 8am and 4pm look like a normal professional sending individual messages throughout their workday.

Most cold email platforms, including SmartLead, allow you to set sending windows and randomise send times within those windows. Configure this properly and let the platform handle the distribution.

Timezone considerations

If you are targeting prospects across multiple timezones, segment your sending accordingly. A campaign targeting both UK and US prospects should have separate sending schedules so that each group receives emails during their local business hours.

This is a small detail that makes a measurable difference. An email that arrives at 3am is not just ignored -- it signals to email providers that the sender is not paying attention to the recipient's context, which is exactly what spam operations do.

Putting It All Together

Here is a summary of the key numbers for a well-structured cold email operation:

These numbers are not arbitrary. They are the result of managing millions of cold emails across multiple clients and industries. They represent the balance point where volume is high enough to generate meaningful pipeline and low enough to maintain the deliverability that makes that pipeline possible.

The temptation is always to push volume higher. The discipline is knowing that deliverability is the constraint, and respecting that constraint is what separates campaigns that generate revenue from campaigns that generate spam complaints.

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