Free tool
Cold email cost calculator.
Pick your monthly sending volume to see what it costs on Mailnitrix, Instantly and Smartlead, and how many mailboxes you need to send it safely.
20,000
- Your Mailnitrix plan
- Launch
- Mailboxes needed
- 17–23 at 30–40/day
MailnitrixLaunch
$19/mo
InstantlyHypergrowth
$97/mo
SmartleadPro
$94/mo
You save each year, compared with the cheaper of the two
$900
Monthly list prices for the cheapest plan (plus Instantly's volume add-on where it is cheaper), checked October 2026. Instantly and Smartlead also cap contacts on each plan; Mailnitrix paid plans don't.
Method
How the numbers are worked out.
Prices are the list prices on each tool's public pricing page, checked October 2026: Instantly and Smartlead. Mailnitrix prices are on our pricing page.
Instantly and Smartlead also limit how many contacts each plan can hold, so a large list may push you onto a bigger plan than your email volume alone would need. The calculator only looks at emails, so their real cost can be higher.
Mailboxes
How many mailboxes you need.
Divide your monthly volume by about 30 days, then by 30 to 40 emails per mailbox per day. 20,000 emails a month is roughly 670 a day, or 17 to 23 mailboxes.
Spread them over two or three domains so one domain's reputation never carries everything, and warm up new mailboxes for two to three weeks first.
FAQ
Calculator questions.
How is the price for each tool chosen?
For each volume we take the cheapest public plan that includes it, on monthly billing. For Instantly we also check whether a smaller plan plus its volume add-on is cheaper. For Mailnitrix we check whether a smaller plan plus extra emails is cheaper than the next plan up. Extra emails on Nitro cost $0.40 per 1,000 up to 400,000, then $0.35 up to 500,000; above that, Enterprise pricing is $0.30 per 1,000 for each additional email.
Why compare monthly billing?
It's the fairest like-for-like. All three tools discount yearly billing: Mailnitrix by up to 21%, Instantly and Smartlead by roughly 17 to 20%.
How many emails can one mailbox send safely?
For cold email, about 30 to 40 a day per warmed-up mailbox is a widely used range. New mailboxes should start lower and build up over a few weeks.
Does the calculator include the cost of mailboxes?
No. All three tools let you connect your own mailboxes, which you pay your email provider for separately. A Google Workspace or Microsoft 365 mailbox typically costs a few dollars a month.
Start sending smarter, for free.
1,000 emails every month on the free plan. No credit card, no time limit.