# What is Hard Bounce?

What is Hard Bounce? An email that failed to deliver due to a permanent reason (address doesn't exist). Must be removed immediately — hurts deliverability.

## How it works in practice

A hard bounce rate above 2% is a serious problem. Most ESPs remove addresses automatically after one hard bounce.

## Related metrics

- Deliverability — a direct hit
- Email List — hard-bounced addresses get removed
- Sender Reputation — a high bounce rate signals spam
- Soft Bounce — a temporary version

## Common misconception

'A 5% bounce rate is fine.' A hard bounce rate above 2% is a serious problem. A healthy average is under 0.5%.

## How to fix it

Rising? (1) stop sending to addresses that bounced, (2) clean the list of suspicious addresses, (3) double opt-in for new subscribers.

## Real-world example

A store imported a list from 2018, causing an 8% hard bounce rate and Gmail routing everything to spam. It took 3 months to recover sender reputation.

## Where to start

Use double opt-in from day one.

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Category: Analytics · From the [Jimmy OS KPI Glossary](https://jimmy-os.com/glossary/kpi.md) · Source page: https://jimmy-os.com/glossary/kpi/hard-bounce