In 30 seconds
- An ideal day is a full day of focused work, with no meetings or interruptions.
- Easier to grasp than points, but easily confused with calendar days.
- Convert to calendar time using a focus factor.
What an ideal day is
Ask: if you could work on just this, with no meetings, email or support, how many days would it take? That's an estimate in ideal days. Mike Cohn described the technique alongside story points in his work on agile estimating.
Converting to calendar time
Real days include interruptions. If a team typically gets 0.6 ideal days of work from each person per day, a 6-ideal-day item takes about 10 working days for one person. The ratio comes from tracking actual results.
Ideal days vs story points
| Ideal days | Story points | |
|---|---|---|
| Easy to explain | Yes | Takes practice |
| Risk | Mistaken for calendar days | Mistaken for hours |
| Depends on who does it | Yes | Less so |
Myth vs reality
Myth · An ideal day is an 8-hour day.
Reality · It's a day with no interruptions, which rarely happens.
Myth · Ideal days are more accurate than points.
Reality · Both are rough; the value is in comparing items.
Myth · Ideal days can't be used in Scrum.
Reality · Scrum doesn't prescribe a unit; teams choose.
FAQ
When are ideal days a good choice?
For new teams or stakeholders uncomfortable with abstract points.
How do I find the conversion ratio?
Compare estimated ideal days with actual calendar time over a few sprints.
Can we mix ideal days and points?
Pick one per team to keep velocity meaningful.