DEFINE THE UNIT
Estimate a repeatable piece of work.
“Build a website” is too broad to compare with one timer entry. “Draft the first version of a landing-page section” is closer to a repeatable unit. Name the expected output, what inputs are available and what review is included.
Separate active effort from elapsed delivery time. A task may require two hours of work but take three days because someone must approve it. Tracking the two work sessions does not measure the waiting automatically. Keep those distinctions when communicating an estimate to another person.
USE A RANGE
Take the middle of a small comparable sample.
Imagine five similar tasks took 35, 40, 45, 60 and 90 minutes of active work. The middle observation is 45 minutes. The range is wide enough that promising every next task will take 45 minutes would be careless.
Read the notes. If the 90-minute task included a missing brief and the next task also lacks one, it may be the most relevant example. If the next task has a complete brief, the shorter examples may fit better. Use a working range such as 40–60 minutes only when the underlying tasks justify it; this is an illustrative method, not a statistical guarantee.
Build a record of completed sessions in Chrono before guessing the next task duration. Get Chrono on Google Play →
REVIEW THE MISS
Record why an estimate missed.
- Scope changed: the requested output grew after the estimate.
- Inputs were missing: preparation or clarification became part of the task.
- Work was interrupted: extra restart effort appeared.
- The task was new: learning was incorrectly treated as routine execution.
One short explanation is enough. Do not add the same percentage buffer to every task and call that learning. Build a few meaningful examples for recurring work and keep unfamiliar work explicitly uncertain.
MAKE HISTORY USEFUL
Give future you enough context.
In Chrono, use an activity for the broad work type and a note or tag for the particular deliverable. Correct forgotten stop times before treating the duration as evidence. CSV export lets you group similar completed tasks in a spreadsheet.
Chrono supplies the record; this guide supplies the estimation method. It does not claim the app predicts completion dates or calculates these ranges for you. For a shared delivery commitment, also account for dependencies, review and available calendar time outside the timer.
05 · QUICK ANSWERS
Estimate Task Duration from Real Time Logs, briefly.
Usually no. Compare several similar tasks and check whether the next task has the same inputs, scope and constraints.
This workflow uses Chrono time entries as evidence and calculates estimates separately. It does not rely on an automatic estimation feature.