Take a cold inbox to full volumewithout tripping the spam filter.
A brand-new inbox that blasts 200 emails on day one looks exactly like a spammer to Google and Microsoft. The fix is a ramp: start small and raise volume a little every day until you hit your target. This planner builds that schedule for you — the day-by-day send counts, how long the ramp takes, and the full-volume date — so you scale into deliverability instead of out of it.
Your ramp
Emails per inbox on day one. Keep it small for a fresh mailbox — 5 to 10 is typical.
Where you want each inbox to land. For cold outreach, 30 to 50/day per inbox is a safe ceiling.
How much you raise volume each day, compounded. ~30% is the safe default; over 50% reads as a spam ramp.
How many mailboxes you're warming in parallel. Capacity scales with this — one inbox can only safely send so much.
The schedule
Days to full volume
8
At your daily increase.
Capacity at full volume / day
120
3 inboxes × 40/day.
Emails sent during warm-up
357
Across all inboxes, start to full.
Day 1 send / inbox
5
Where every mailbox starts.
First days of the ramp (per inbox)
Your daily increase, against safe bands
The daily increase is the number that gets inboxes filtered. Stay at or under ~35%/day and a fresh domain reads as a real person scaling up. Push past 50% and you look like a spammer.
Reverse-solve · days to a different target
Days to reach it
8
Fleet capacity there
120
From 5/day at +30%/day, climbing to 40/inbox/day takes about 8 days. Across your 3 inboxes that's 120 emails a day at full volume. A higher target only adds a handful of days — the increase, not the ceiling, sets the pace.
Sensitivity · how steep is too steep
The same target, three ramp speeds
| Daily increase | Days to full | Sent during ramp / inbox |
|---|---|---|
| 20% | 12 | 197 |
| 30% | 8 | 119 |
| 50% | 6 | 104 |
Your start (5) and target (40) are fixed across this table — only the daily increase changes. Going from 20% to 50%/day saves a few days but trades real reputation risk for them. 50%+ is where mailbox providers start treating you as a threat.
Your move
A clean ramp gets you in the inbox. The campaign behind it gets you booked.
Warm-up from 5 to 40 emails/inbox/day takes 8 days at +30%/day → 120/day across 3 inboxes.
This schedule keeps your domain healthy — but a warmed inbox sending bad emails to a bad list is still a dead campaign. Bring me your outbound setup and on a free 30-minute call I'll pressure-test your warm-up, authentication, list, and copy, and tell you exactly what's between you and booked meetings.
Conservative: 10-20% / day — Safest. Longer ramp, almost no spam-folder risk. Standard: 25-35% / day — The sweet spot. Fast enough to be useful, gentle enough to stay safe. Aggressive: 40-50% / day — Only on aged, well-warmed domains. Watch placement daily. Reckless: 50%+ / day — Mailbox providers read this as a spammer ramping up. Expect the spam folder.
Plain English
Warm-up is reputation, built one day at a time
Every mailbox starts with no sending reputation. The moment it sends real volume, inbox providers watch how it behaves: how much it sends, how fast that grows, how recipients react. A cold inbox that goes from zero to 200 a day overnight matches the exact signature of a compromised or spammy account — so the safe ones get throttled and the rest land in spam. Warm-up is how you build the reputation that keeps you in the inbox.
The mechanic is simple: start at a small daily volume your fresh inbox can send credibly, then raise it by a fixed percentage every day. Because the increase compounds, you reach full volume surprisingly fast — a 30% daily bump roughly doubles your send every three days. The math is just a geometric ramp: days-to-target depends only on how far apart your start and target are and how steep your daily increase is.
This planner turns that into a real schedule. Give it your starting send, your target, and how aggressively you want to climb, and it returns the number of days to full volume, the first ten days of exact send counts, your full capacity once warmed, and a verdict on whether your daily increase is safe or asking to be filtered. Pair it with proper SPF, DKIM, and DMARC and you've got the deliverability foundation most cold senders skip.
The formula
Day n volume = start × (1 + increase)^(n−1) → Days to target = ⌈ log(target ÷ start) ÷ log(1 + increase) ⌉
Start 5/day, target 40/day, +30%/day. Days = ⌈ log(40 ÷ 5) ÷ log(1.30) ⌉ = ⌈ log(8) ÷ log(1.30) ⌉ ≈ ⌈ 7.9 ⌉ = 8 days. Day 1 sends 5, day 4 sends ~11, day 8 sends ~31, and you cap at 40 from day 9 on. Across 3 inboxes that's 120/day at full volume.
Safe ramp speeds (rule of thumb)
Inbox providers don't publish a warm-up curve, so treat this as a heuristic, not a law. The single number that gets people filtered is the daily increase: stay in the conservative-to-standard band, and only push the aggressive band on aged domains you've already warmed once.
| Ramp speed | Daily increase | What it does |
|---|---|---|
| Conservative | 10-20% / day | Safest. Longer ramp, almost no spam-folder risk. |
| Standard | 25-35% / day | The sweet spot. Fast enough to be useful, gentle enough to stay safe. |
| Aggressive | 40-50% / day | Only on aged, well-warmed domains. Watch placement daily. |
| Reckless | 50%+ / day | Mailbox providers read this as a spammer ramping up. Expect the spam folder. |
Rule-of-thumb deliverability bands — not a published dataset. Inbox providers don't publish a warm-up curve. The daily increase is the lever that gets you filtered: start small, stay in the conservative-to-standard band, and never jump more than ~50% a day.
Your ramp looks risky. What's the fix?
Daily increase over ~50%.
This is the fastest way into the spam folder. A near-doubling every day is the textbook spammer signature. Drop to 25-35%/day — you'll lose only a few days and keep your reputation intact.
Start volume above ~15 on a brand-new inbox.
Day-one volume matters as much as the climb. A fresh mailbox sending 20+ cold emails on day one has no reputation to justify it. Start at 5-10 and let the ramp do the work.
Target above ~50/inbox/day for cold outreach.
One inbox can only send so much cold mail safely. Past ~50/day per mailbox, add inboxes instead of raising the ceiling — spread volume across more warmed mailboxes, not harder onto one.
Ramp finishes in under ~4 days.
Either your start and target are very close (fine) or your increase is too steep (not fine). A real warm-up usually spans one to three weeks. If yours is over in days, slow the daily increase down.
How to warm up without burning the domain
01Start small, climb slow
5-10 emails on day one, +25-35%/day. The compounding gets you to full volume in a couple of weeks while looking entirely human the whole way.
02Send to real, engaged people first
Early sends should go to addresses that open and reply. Engagement is the strongest positive reputation signal there is — seed the ramp with warm contacts.
03Authenticate before you send a thing
SPF, DKIM, and DMARC are table stakes. An unauthenticated domain gets filtered no matter how gentle the ramp. Set them up first.
04Warm across multiple inboxes
Don't push one mailbox to its limit. Run several inboxes in parallel at safe volumes — more total capacity, zero extra risk to any single domain.
05Watch placement, not just opens
Use seed tests to confirm you're landing in the inbox, not the Promotions tab or spam. Pause the ramp if placement slips and let reputation recover.
06Keep volume steady once warmed
Reputation decays if you stop. After the ramp, hold a consistent daily volume — wild swings up or down both look suspicious to filters.
07Protect the reply rate
High bounce and spam-complaint rates undo a perfect ramp. Verify your list and write emails people actually answer — deliverability is a behavior score, not just a volume one.
08Don't restart from zero needlessly
A warmed inbox that's been sending steadily doesn't need re-warming for a minor volume change. Re-ramp only after a long pause or a reputation hit.
The vocabulary
- Warm-up
- Gradually increasing an inbox's daily send volume to build sending reputation before running it at full capacity.
- Daily increase
- The compounding percentage you raise volume by each day. The single biggest factor in whether a ramp looks safe or spammy.
- Sending reputation
- The trust score mailbox providers assign your domain and IP based on volume, consistency, and how recipients react.
- Full volume
- Your target steady-state send rate per inbox per day, reached at the end of the ramp.
- Throttling
- When a provider deliberately slows or limits delivery from a sender it doesn't yet trust — common during a too-fast ramp.
- Seed test
- Sending to a set of monitored test inboxes across providers to see whether you're landing in the inbox or spam.
Email warm-up questions, straight answers
Usually two to four weeks for cold outreach. The exact length depends on how far apart your start and target volumes are and how fast you climb: at a safe ~30%/day increase from 5 to 40 emails a day, the ramp itself is about 8 days, and most teams then hold there for another week or two before pushing volume. This planner gives you the precise day count for your own numbers.
Keep going
A calculator tells you what. A call tells you what to do about it.
Send me the account behind these numbers. I'll tell you straight where the money's leaking and what I'd fix first — free, and you keep it whether you hire me or not.