Ideal Time

⏱ 3 min  ·  📅 2026

Ideal time (also called "task time") is the estimated time needed to complete a task under conditions of full concentration: without interruptions, calls, meetings, context switching, or any other distraction. It is the unit of effort commonly used in agile estimates, as opposed to elapsed time, which includes all of that friction.

The concept is equivalent to what PSP (Personal Software Process) calls "Delta Time": the portion of working time that is genuinely effective work time.

Ideal time vs. elapsed time

The difference between the two has direct implications for planning:

• Elapsed time: the actual working day. For a team of four people working eight-hour days, the elapsed time in one week is 4 × 8 × 5 = 160 hours.
• Ideal time: working time under optimal conditions of concentration, without the usual friction.

A basketball game lasts 40 minutes of exact playing time, but the actual game usually runs over an hour. Likewise, a task that "takes three ideal hours" may take up half a working day of elapsed time, because the three hours of effective work are interspersed with meetings, interruptions, and context switches.

Consciously managing this difference helps teams commit to realistic sprints and avoid the stress of goals that seem achievable in ideal time but not in elapsed time.

When it is used

• In task estimates: "This task has a size of 4 ideal hours" is a valid estimate, as long as whoever plans the sprint knows that 4 ideal hours do not equal half a working day in elapsed time.
• In capacity-based planning: when calculating how much work the team can take on in a sprint, you start from the available elapsed time and apply a conversion factor to estimate the available ideal time.

Common mistake

Planning the sprint in ideal time without applying a conversion factor. Assuming that the team can work in a state of full concentration throughout the entire working day leads to commitments the team cannot meet. In practice, meetings, interruptions, and non-productive work consume between 30% and 50% of elapsed time. Realistic planning deducts that time before committing to the sprint's work.

See also

Velocity, work, and time Production time Timeboxing Capacity-based Planning Sprint PSP

Want to advance in agility? You can search for course and exam calls, or go at your own pace by becoming a member of the Agile Club. This membership includes exclusive resources, e-learning classrooms, and access to Skill Arena: a space to practice and measure your agile skills at your own pace.

Find calls

Agile Club