How many cold emails can you send per day per inbox?

Why is 30 a day the safe number?

Because inbox providers judge cold email on reputation, not on what the mailbox is technically allowed to send. Add an inbox and the risk gets shared. Squeeze more out of one inbox and the risk piles up in one place.

Three cold email platforms publish their own guidance for customers. Here it is side by side (as of September 2026):

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We sit at the careful end on purpose. Opening at 30 leaves headroom for the week a campaign runs hot, and it's the same number our pipeline calculator uses.

One lemlist warning is worth reading twice: it says mailboxes on the same provider share one reputation, so ten Google inboxes are not ten separate budgets. As you grow past a handful of inboxes, spread them across fresh domains and, eventually, across providers (Google and Microsoft).

What are Google's and Microsoft's actual sending limits?

Far above anything you should use for cold email. These are the points where the provider cuts you off, not the level where your reputation stays safe.

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Put those side by side with our guideline: 2,000 is about 67 times 30. The cap that matters isn't the provider's. It's your spam complaint rate, which Google wants under 0.3%, with a target under 0.1% (Google Email sender guidelines). The more you send from one inbox, the more of those complaints stack up on one reputation.

If your sending tool connects through the Gmail API or SMTP, extra per-message caps apply. Your sending platform deals with those.

How many inboxes do you need for your volume?

Take your daily sends and divide by 30: that's your inbox count. Halve it for domains. The planner below uses our guidelines: about 30 cold sends per inbox per day, 2 inboxes per domain, 21 sending days a month, 5 touches per new prospect (an initial email plus 4 follow-ups on days 0, 3, 7, 10 and 14).

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Prices as of September 2026: Google Workspace Business Starter at $8.40 per user a month (Flexible plan) or $84 a year (Annual plan), per Google's Workspace billing help pages; Porkbun .com at $11.08 a year. The math, row 2: 4 inboxes × 30 × 21 = 2,520 sends; 2,520 ÷ 5 = 504 prospects; 2 domains × $11.08 ÷ 12 = $1.85. Microsoft 365 Business Basic costs less per inbox ($5.40 a month paid yearly for the version without Teams; $7.00 with Teams); the cheapest cold email stack has the full comparison.

Don't read the 1-inbox row as advice. It shows why nobody runs cold email from a single mailbox: 126 new prospects a month won't fill a pipeline.

No daily number yet? Start from your meeting target in the Pipe Playbook calculator and work backward.

Which sending plan fits your volume?

Line up the plan's monthly send allowance with the "sends a month" column above. Limits come from each vendor's pricing page, as of September 2026.

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All three connect unlimited inboxes (lemlist's Email plan calls them unlimited senders) and include warmup, so adding inboxes doesn't raise the platform bill. Head-to-head: Instantly vs Smartlead vs lemlist. Wider lineup: best cold email software.

When should you skip each platform?

One skip line per tool, from the plan table above.

• Instantly Growth: skip it if you'll send more than 5,000 emails a month or upload more than 1,000 contacts in total. Row 2 above is already 2,520 sends, and it fills the contact cap in about two months.
• Smartlead Base: skip it if you need CRM access, an API or webhooks. They start at Pro ($94 a month, or $78.30 billed annually).
• lemlist Email: skip it if you need LinkedIn or call steps in the same sequence. The Email plan is email only.

What's the hidden overhead on top of the platform bill?

The planner above prices only inboxes and domains. Add list verification and the Instantly plan that fits each row (the pick used on our cheapest cold email stack page; Smartlead Base at $39 is cheaper for the first two rows but has no CRM access or API) and you get the full monthly total. Prices as of September 2026: Google Workspace Business Starter at $8.40 flexible or $7.00 on a yearly plan, Porkbun .com at $11.08 a year, and MillionVerifier at $0.00178 a credit (its $89 pack of 50,000), one credit per new prospect. Warmup is $0 on all three platforms because it's included. Contact data is not in these totals.

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Verification is each row's prospects a month × $0.00178 (126, 504, 1,512 and 3,024 prospects). Rows 2 and 3 match the worked examples on our cheapest cold email stack. Both upload caps are fixed totals, not monthly allowances: Instantly Growth's 1,000 contacts last about 8 months at row 1's pace (1,000 ÷ 126) but only about 2 months at row 2's (1,000 ÷ 504), and Hypergrowth's 25,000 last about 8 months at row 4's pace (25,000 ÷ 3,024). Delete finished leads or move up a plan when you hit them.

Does warmup count toward the 30?

Depends whose rules you follow. Instantly's help center says warmup emails don't count toward its account and campaign limits. lemlist counts everything: lemwarm runs at about 10 a day on top of your 30–40, and the total, manual replies included, stays under 70 per provider. Either way, the 30 means cold emails to real prospects.

A new inbox doesn't open at 30. It climbs there, over a ramp of about 30 days. Our domain warmup guide walks through it, and the best email warmup tools page covers standalone options if your sender has no warmup built in.

When should you send fewer than 30?

Pull volume back as soon as one of these appears. They're alarms, not goals.

1. Spam rate creeps toward 0.3% in Google Postmaster Tools. Google's target is under 0.1% (Google Email sender guidelines). See what spam complaint rate is too high.
2. Bounces go past 2%. Our guideline is to pause above 2%; Google and Microsoft publish no bounce threshold. Pause, re-verify the list, restart lower. Our pick: best email verification tool.
3. Replies fall while opens still look "fine." You may be landing in spam. Work through why are my cold emails going to spam.
4. The domain is less than a month old. Stay on the warmup ramp. lemlist keeps a domain that young under 100 emails a day, all its mailboxes combined.
5. You're coming back from a bad week. lemlist's help center restarts a mailbox at about 15 a day and climbs in steps of 3. Rebuild from there.

Why more inboxes beat more volume per inbox

Replies come from relevance and follow-ups, not from hammering one mailbox. Instantly's Cold Email Benchmark Report 2026 put the average reply rate on Instantly's platform at 3.43% (replies divided by total emails sent, so per email, not per prospect) and found 42% of replies come from follow-ups. Woodpecker's report on 16.5M emails shows campaigns to under 50 recipients got 5.8% replies versus 2.1% for 500 or more.

So here's the play: tight segments, enough inboxes to hold each one near 30 a day, and the full 5-touch sequence behind every prospect. First email under 80 words (Instantly 2026), then follow-ups on days 3, 7, 10 and 14. Template: the cold email follow-up sequence.