What cold email really costs in 2026: inboxes, domains and tools
Real 2026 cold email costs by inbox type: Google $2–3/inbox, Outlook $0.30–0.40, SMTP $0.50–0.99. A 100k/month stack runs about $360 in inboxes.
- There are four inbox types, and they cost very different amounts per inbox: Google Workspace $1.99–2.99, Outlook Premium $0.40, Outlook Normal $0.30 and Private SMTP $0.50–0.99.
- Cost per inbox is the wrong number to compare. What matters is cost per 1,000 sends: about $2.40 on Outlook Premium, $2.00 on SMTP and $9 on Google.
- A diversified stack of 50% Outlook, 30% SMTP and 20% Google costs about $360 a month in inboxes for 100,000 sends, or about $3.60 per 1,000.
- Keep 50% extra capacity warm as a reserve. That takes the same 100k stack to about $540 a month.
- The sequencer is the smallest line, and it doesn't change deliverability. Inbox type, domain health, copy and list quality do.
Most cold email cost breakdowns take a public list price, multiply it by a guess at how many inboxes you need, and call it done. That gives you a number that's wrong in both directions. It overpays for the inboxes doing the bulk of the sending, and it ignores how few emails each inbox type can safely send.
This breakdown uses our own operating data: Scaling Room's 2026 Q3 inbox-types data, the numbers we run client infrastructure on. Every total below is shown with its formula, so you can plug in your own volume.
What are the four cold email inbox types, and what do they cost?
Every provider and reseller sells you one of four things. Know which one you're buying.
| Google Workspace | Outlook Premium | Outlook Normal | Private SMTP | |
|---|---|---|---|---|
| Price | $2.99 (Starter) / $1.99 (Base) per inbox | $40 per domain (100 inboxes) | $30 per domain (100 inboxes) | $0.50–0.99 per inbox |
| Cost per inbox | $1.99–2.99 | $0.40 | $0.30 | $0.50–0.99 |
| Inboxes per domain | 5 | 100 | 100 | 5 |
| Cold sends per inbox per day | 15–20 | 8–10 | 3–5 | 11–14 |
| Sends per domain per month | ~2,000 | ~18,000 | ~8,000 | ~1,300 |
| Warm-up before first cold send | 15–25 days | 3–5 days min, 10–14 ideal | 5–7 days min, 10–14 ideal | 3–4 weeks min |
| Deliverability rank | #1 (baseline) | #2 (~15–20% below Google) | #3 (~20–25% below Google) | #4 (~35–50% below Google) |
Monthly figures assume about 20 sending days.
Two things jump out. Outlook tenants carry 100 inboxes per domain, so one Outlook Premium domain does the monthly volume of nine Google domains. And Google, the most expensive per inbox and the slowest to warm up, delivers the best.
Why cost per inbox is the wrong number
A $0.30 inbox that sends 4 emails a day isn't cheaper than a $2.99 inbox that sends 17. You have to divide by what each inbox can actually send:
cost per 1,000 sends = cost per inbox ÷ (sends per inbox per day × 20 days) × 1,000| Inbox type | Cost per inbox | Sends per inbox per month | Cost per 1,000 sends |
|---|---|---|---|
| Google Workspace (Starter) | $2.99 | ~350 | ~$8.50–9.00 |
| Google Workspace (Base) | $1.99 | ~350 | ~$5.70–6.00 |
| Outlook Premium | $0.40 | ~180 | ~$2.20–2.40 |
| Outlook Normal | $0.30 | ~80 | ~$3.75 |
| Private SMTP | $0.50 | ~250 | ~$2.00 |
Outlook Premium and SMTP are the cheap volume. Google is the premium layer you pay for on purpose. Outlook Normal looks cheapest per inbox, but it costs more per send than Premium because each inbox sends less. At the same domain count, Premium gives you more than twice the volume for 33% more money.
What does a 100,000-a-month stack cost?
Don't run a single provider. When one burns or has an outage, a diversified stack keeps sending. The split we run as standard:
- 50% Outlook Premium: the primary workhorse. High trust, fast warm-up, high volume per domain.
- 30% Private SMTP: a cheap volume buffer. It absorbs spikes and protects the other layers, and it's replaceable if it burns.
- 20% Google Workspace: the premium layer, saved for your best segments and highest-value leads.
Here's that stack at 100,000 sends a month, sized from the per-inbox rates above:
| Layer | Sends per month | Inboxes | Domains | Monthly cost | Per 1,000 sends |
|---|---|---|---|---|---|
| Outlook Premium (50%) | 50,000 | 300 | 3 | $120 | $2.40 |
| Private SMTP (30%) | 30,000 | 120 | 24 | $60 | $2.00 |
| Google Workspace (20%) | 20,000 | 60 | 12 | $179 | $8.97 |
| Total | 100,000 | 480 | 39 | ~$359 | ~$3.59 |
That's inbox cost only. Domain registration is on top: 39 domains here, priced by your registrar and TLD. Google on the Base tier instead of Starter brings the Google layer to about $119 and the total to about $299.
Why you should budget for 50% more capacity
The table above is the capacity you send with. Our rule is to keep another 50% warm in reserve. Then if a provider goes down or a batch of domains burns, the volume moves to warm inboxes the same day, instead of waiting two to four weeks to warm up replacements.
| Monthly volume | Inboxes (sending) | Domains (sending) | Inbox cost | With 50% warm reserve |
|---|---|---|---|---|
| 100,000 | 480 | 39 | ~$359 | ~$540 |
| 150,000 | 770 | 59 | ~$559 | ~$840 |
| 300,000 | 1,435 | 116 | ~$1,063 | ~$1,600 |
Where does the sequencer fit in?
The sequencer is the smallest line in this budget, and it doesn't make you deliver better. It schedules sends. Deliverability comes from inbox type, domain health, list quality and copy, and above all from how often recipients mark you as spam. Inbox type accounts for roughly 60% of the outcome; domain health and copy make up the rest.
So don't pay a premium for a "deliverability" sequencer. Pay for what it saves you in operations. On Zylar's Growth plan, $97 a month covers 150,000 emails with unlimited inboxes, seats and campaigns. Warm-up is free and doesn't count toward sends, and every plan includes verification and enrichment credits. It also handles the work that eats operator hours on a stack this size: DNS checks the moment you connect a domain, rotation across hundreds of inboxes, placement tests per domain, and auto-pausing a domain the moment it slips. Inboxes are available through MailDeck as an add-on.
What you still pay for separately: the inboxes, the domains, and any verification beyond your plan's credits. At 100,000 sends of a 3-step sequence you're reaching about 33,000 new contacts a month, well beyond Growth's 5,000 verification credits.
The hidden cost: running it yourself
At 39 to 59 domains and 500 to 800 inboxes, someone has to:
- buy domains and set up redirects
- publish SPF, DKIM and DMARC for every domain and keep them correct
- warm up each inbox type on its own schedule
- watch placement per domain and pull domains that slip
- replace burned domains and re-warm their replacements
That's the work managed infrastructure removes. The managed version of this stack at MailDeck, our sister company, is $400 a month for 100,000 sends, including DNS and authentication setup, dedicated Slack support and free domain replacement. Whether that beats doing it in-house depends on what your operator's hours cost.
FAQ
How much does cold email cost per month?
For 100,000 sends a month on a diversified Outlook, SMTP and Google stack, budget about $360 a month for inboxes, or about $540 with a 50% warm reserve. Domain registration and your sequencer come on top. Per 1,000 sends that's about $3.60 in inbox cost.
Which inbox type is cheapest for cold email?
Per 1,000 sends, Private SMTP (~$2.00) and Outlook Premium (~$2.40) are the cheapest. Outlook Normal is cheapest per inbox at $0.30, but each inbox sends only 3–5 a day, so it costs more per send than Premium. Google Workspace is the most expensive per send, at about $6–9 per 1,000, and also the best at delivering.
Is Google Workspace worth it for cold email?
Yes, for the right 20% of your volume. Google ranks first for deliverability, so use it for C-suite, enterprise and high-value segments where one reply is worth a lot, and as a clean A/B control. Don't use it as your bulk layer. It's the slowest to warm up, at 15–25 days, and the most expensive per send.
How many domains do I need for 100,000 cold emails a month?
About 39 domains on a 50/30/20 Outlook, SMTP and Google stack: 3 Outlook Premium, 24 SMTP and 12 Google. Add 50% for a warm reserve. See how many inboxes you need for the formula at other volumes.
Does the sequencer affect deliverability?
No. A sequencer schedules and rotates sends. Inbox placement is decided by inbox type, domain reputation, list quality and copy. A good sequencer protects deliverability operationally: it catches a slipping domain early, caps sends per inbox and rotates evenly. It doesn't make a bad inbox deliver.
