Your list-health vitals,before the provider throttles you.
Bounces, unsubscribes, and delivery rate are the early-warning lights on your sender reputation. Cross the wrong threshold and your inbox placement quietly collapses — for every campaign, not just the next one. This tells you exactly where you stand and what's about to break.
Your numbers
Total messages attempted for this send or period.
Permanent failures: dead address, invalid domain, blocked sender. These never deliver.
Temporary failures: full mailbox, server down, message too large. May deliver on retry.
People who opted out from this send. The honest version of a bounce.
The verdict
Bounce rate
1.2%
Delivery rate
98.8%
Hard bounce rate
0.8%
Keep under 1%. The fastest way to wreck a reputation.
Unsubscribe rate
0.3%
A relevance signal. Keep under 0.5%.
Delivered
9,880
Total bounces
120
Where the send went
Bounce rate vs. the 2% red line
Reverse-solve · stay under a ceiling
Bounces allowed
200
Headroom
80
On 10,000 sends, a 2.0% ceiling lets you absorb 200 bounces. You currently have 120 — 80 of room left before you breach it.
Sensitivity · the cost of dead addresses
What hard bounces do to your rate
| Hard bounces | Hard bounce rate | Verdict |
|---|---|---|
| 0 | 0.0% | Safe |
| 25 | 0.3% | Safe |
| 50 | 0.5% | Safe |
| 100 | 1.0% | Safe |
| 200 | 2.0% | Watch it |
| 400 | 4.0% | Reputation damage |
On 10,000 sends, the 1% hard-bounce line is just 100 dead addresses. That's how little it takes for a provider to start watching — which is why validation and suppression aren't optional.
Your move
Your list is leaking reputation. I find the holes.
1.2% bounce rate on 10,000 sends → 98.8% delivered, 0.8% hard bounces.
Send me your last few campaigns' numbers and I'll tell you whether your problem is the list, the authentication, the content, or the send strategy — and what I'd fix first to get you back in the inbox. Free, and you keep the plan whether you hire me or not.
Plain English
Bounce rate is a reputation score in disguise.
Your bounce rate is the share of emails that never reached an inbox because the send failed. Hard bounces are permanent (the address is dead, the domain doesn't exist, you're blocked); soft bounces are temporary (the mailbox is full, the server hiccuped). Mailbox providers watch both, but hard bounces hurt far more — each one is proof you're mailing addresses you shouldn't have.
Here's why it matters beyond a single send: Gmail, Outlook, and Yahoo treat a rising bounce rate as a signal that you're not maintaining your list. Cross roughly 2% and inbox placement starts slipping. Push past 5% and providers begin throttling or junking your mail wholesale — which tanks delivery for your clean subscribers too. A bounce problem isn't one bad campaign; it's a tax on every campaign that follows.
This calculator turns your raw send numbers into the four vitals that actually predict trouble: bounce rate, delivery rate, hard bounce rate, and unsubscribe rate. It grades each against the thresholds deliverability teams use, so you find out you have a list-hygiene problem before a provider finds out for you.
The formula
Bounce rate = (Hard bounces + Soft bounces) ÷ Emails sent × 100
Send 10,000, with 80 hard bounces and 40 soft → 120 total bounces ÷ 10,000 = 1.2% bounce rate, and 9,880 delivered = 98.8% delivery rate. Hard bounce rate is 80 ÷ 10,000 = 0.8% — under the 1% danger line. Clean. Now triple the hard bounces to 240 and you're at a 0.8% → 2.4% hard bounce rate: same list, but now the provider is watching.
What good looks like
These aren't aspirational targets — they're the ceilings deliverability teams treat as red lines. Stay under them and your sender reputation holds; breach them and inbox placement starts eroding:
| Metric | Keep it under |
|---|---|
| Bounce rate | 2% |
| Hard bounce rate | 1% |
| Unsubscribe rate | 0.5% |
Source: Email list-health benchmarks (Mailchimp / Validity) · 2025
Your numbers came back ugly. Now what?
Hard bounce rate over ~1%.
This is the emergency. Stop sending to the bouncing segment immediately and run the list through validation (NeverBounce, ZeroBounce, Kickbox). Hard bounces are the single fastest way to wreck a sender reputation. Suppress, don't retry.
High bounces on a brand-new list.
You bought or scraped it, or imported an old export. Purchased and stale lists are bounce factories. Validate before the first send and warm up slowly — never blast a cold list at full volume.
Bounce rate fine, unsubscribes high.
Deliverability is healthy but relevance isn't. You're reaching the inbox and people are leaving. Tighten segmentation, cut send frequency, and fix the content — high unsub is a content problem, not a list problem.
Soft bounces high, hard bounces low.
Often transient: a provider outage, oversized HTML, or aggressive sending speed. Slow your send rate, trim image weight, and watch whether soft bounces convert to hard over repeated sends — repeat soft bouncers should eventually be suppressed.
Eight ways to protect your list health
01Validate before you send
Run new and imported lists through an email-verification service. Catching dead addresses before the send keeps hard bounces off your record entirely.
02Use double opt-in
Confirmed opt-in filters out typos, bots, and fake addresses at the source. It shrinks your list slightly and your bounce rate dramatically.
03Suppress hard bouncers permanently
Any address that hard bounces once should be auto-suppressed forever. Mailing it again is pure reputation damage with zero upside.
04Sunset inactive subscribers
Stop mailing people who haven't opened in 6–12 months. Dead weight raises bounces and spam complaints and drags inbox placement down for everyone.
05Warm up new domains and IPs
Ramp volume gradually on fresh sending infrastructure. A cold IP blasting 100k emails looks exactly like a spammer to mailbox providers.
06Authenticate with SPF, DKIM, DMARC
Proper authentication is table stakes. Without it, more of your mail soft-bounces or lands in spam regardless of list quality.
07Make unsubscribe easy
A one-click unsub is far better than a spam complaint. Complaints hurt reputation more than unsubscribes ever will — give people the clean exit.
08Watch trends, not single sends
One noisy campaign is noise. A bounce rate creeping up send over send is the signal. Track the trend so you act before a provider does.
The vocabulary
- Bounce rate
- Share of sent emails that failed to deliver: (hard + soft bounces) ÷ sent. The headline list-health metric.
- Hard bounce
- A permanent delivery failure — invalid address, nonexistent domain, or a block. Should be suppressed forever after one occurrence.
- Soft bounce
- A temporary failure — full mailbox, server down, oversized message. May deliver on retry; repeat soft bounces should eventually be suppressed.
- Delivery rate
- Share of sent emails that didn't bounce: delivered ÷ sent. Not the same as inbox placement, which also counts spam-foldered mail.
- Unsubscribe rate
- Share of recipients who opted out from a send. A relevance and frequency signal — not a deliverability failure, but watched all the same.
- Sender reputation
- The trust score mailbox providers assign your domain and IP. Bounces, complaints, and engagement all feed it; it decides inbox vs. spam.
Bounce rate questions, straight answers
Keep your overall bounce rate under 2% and your hard bounce rate under 1%. Above 2% you're in caution territory; sustained above 5% and mailbox providers will start throttling or junking your mail. The best-maintained lists sit well under 1% total because they validate and suppress aggressively.
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.