About 66 seconds for every unwanted email. That adds up three costs. Where a published study measured a cost, we use its figure; where none did, we use our own estimate and say so.
| Cost of one unwanted email | Seconds | Source |
|---|---|---|
| Reviewing and deleting it | 16 | Nucleus Research, Spam: The Repeat Offender (2007), a survey of 849 email users: 16 seconds per message reviewing and deleting spam. |
| Getting back to work after it interrupts you: 70% of emails × 64 seconds | 44.8 | Jackson, Dawson & Wilson, Reducing the effect of email interruptions on employees, International Journal of Information Management (2003). From 28 days of recorded work, people acted on 70% of emails within 6 seconds of arrival, and took 64 seconds on average to return to their previous work at the same pace. |
| Seeing it again in your inbox while looking for the emails you want: 5 glances × 1 second | 5 | This is our own estimate. A glance reads the sender and a few words of the subject: about 4 words in 1 second at the average adult silent reading rate of 238 words per minute (Brysbaert, Journal of Memory and Language, 2019). People open their email a median of 58 times a workday (Mark et al., CHI 2016), so 5 glances assumes an unwanted email stays in view for about 41 minutes. |
| Total per unwanted email | 65.8 |
The three email studies measured office workers and date from 2003, 2007 and 2016. Jackson et al. observed 15 employees at one company, and Nucleus Research's figure is what survey respondents reported. The reading rate comes from a 2019 review of reading-speed research on adults, not from a study of email. We count only the three costs above and leave out others, such as the longer time it can take to refocus when checking email leads to other distractions.
Saved per day: for every user who has been with us at least 7 days and had an email bounced in the last 30 days, we count how many emails we bounced for them per day over those 30 days, or since they joined if that was more recent. We average that across users and multiply by the time per unwanted email above. Emails that were bounced and then delivered to the inbox after all are not counted.
Less inbox noise: for every user who has been with us at least 7 days and has received at least 10 emails, the share of their incoming email that InboxBouncer bounced, averaged across those users.
Emails blocked: the total number of emails InboxBouncer has bounced for all users.
All three are recalculated once a day.