ETA Calculator

The ETA Calculator estimates when a batch of repetitive work will be finished. Tell it when you start, how many units of work there are, and how long a single unit takes — it multiplies out the pace, adds any break time and a safety buffer, and reports both the total working duration and an exact estimated finish date and time. Optionally, it can spread the work across working hours only (9am–5pm) or skip weekends, so the estimate reflects a realistic schedule rather than a non-stop clock.

It is useful for anything paced and countable: processing a queue of tickets, packing orders, rendering frames, transcribing recordings, running a test batch, or migrating records.

How to use it

1. Start time — the moment work begins, in YYYY-MM-DDThh:mm format (24-hour clock), e.g. 2026-07-13T09:00.
2. Total units — how many items, tasks, or steps there are.
3. A unit finished every — the pace: a number plus a unit (milliseconds through years). For example, 3 and Minutes means one unit every three minutes.
4. Break time (optional) — a flat block of non-working time to add on top (a lunch break, a maintenance pause).
5. Buffer time % (optional) — an extra percentage added to the whole estimate to absorb unexpected delays. 10 adds 10%.
6. Working hours only (optional) — if checked, work only accrues between 9am and 5pm; evenings roll over to the next day.
7. Exclude weekends (optional) — if checked, Saturdays and Sundays are skipped entirely.

The results update as you type: Estimated finish time shows the calculated completion moment, and Total working duration shows the raw active work time before any scheduling constraints are applied.

How the estimate is calculated

Active work time = (total units × pace per unit) + break time, then multiplied by 1 + buffer%. When neither scheduling option is enabled, the finish time is simply the start time plus that duration. When Working hours only and/or Exclude weekends are enabled, the calculator walks forward from the start moment and only counts time inside the allowed windows, so the finish time lands on the next valid working period rather than in the middle of a night or weekend.

Why does the finish time ignore my computer's timezone?

The calculator treats your start time as a plain wall-clock value and does all arithmetic on that same clock, so the answer never shifts because of daylight saving or the timezone of whatever device you're on. Read the finish time in the same local sense you entered the start time.

What do "Months" and "Years" mean as a pace unit?

They are approximations for quick estimates: a month is treated as 30 days and a year as 365 days. For calendar-exact long-range planning, use days or hours.

Why is my finish time a whole workday later than expected?

With Working hours only, each day contributes at most 8 hours (9am–5pm). Any remaining work past 5pm resumes at 9am the following day (skipping weekends too, if that option is on). Long batches therefore stretch across several calendar days even when the total working duration is small.

Does the buffer apply to breaks as well?

Yes. The buffer percentage is applied to the combined total of work time plus break time, so it scales the entire estimate.

Privacy

The ETA Calculator runs entirely in your browser. Your start time, unit counts, and settings are never uploaded, logged, or stored — the calculation happens locally on your device.