Annotation cost and time calculator
Estimate what an annotation study will cost and how long it will take before you launch it. Enter the number of items, annotators per item, time per item, and pay rate, and the calculator adds paid training, attention checks, adjudication, and the platform fee for Prolific or Amazon Mechanical Turk. The arithmetic runs in your browser.
The task
The people
Pay and platform
Total cost
$1,020
$0.51 per item
Paid hours
60.8 h
annotation, training and adjudication
Working days
1.4
20 annotators at 2 h a day
One more annotator per item
+$280
added to the total
Breakdown
| Annotation | 52.5 h | $630 |
| Training | 5 h | $60.00 |
| Platform fee (33.3% of annotator pay) | $230 | |
| Adjudication | 3.3 h | $100 |
| Total | $1,020 |
At this rate an annotator earns $0.10 per item, the reward to set on platforms that pay per task.
Annotation hours for the starting values
Annotation time is items × annotators per item × seconds per item, plus the attention checks mixed in with the real items. The starting values describe a study of 2,000 items, three annotators each, 30 seconds per item, and 5% check items, which comes to 52.5 hours of annotation. Paid training for a pool of 20 annotators adds five hours, adjudicating 10% of the items adds 3.3 hours, and at $12 an hour on Prolific's academic rate the study costs about $1,020, or $0.51 per item.
Seconds per item multiplies the annotation cost just as the item count and annotators per item do, and it is the input most often guessed. Run a pilot of 50 to 100 items with the real interface and use the median time per item, since a few annotators who leave a tab open can pull the mean far above what most people take. An estimate that is off by a factor of two in time per item is off by the same factor in annotation cost, and a pilot of 50 to 100 items costs 2.5% to 5% of a 2,000-item study.
Platform fees and minimum pay
Crowdsourcing platforms charge a fee on top of what annotators earn, and the calculator applies it to annotation and training pay but not to adjudication, which the calculator assumes you pay outside the platform. The rates below are the published ones, checked on Prolific's pricing page and MTurk's requester pricing in October 2026.
| Platform | Fee on annotator pay | Pay rules |
|---|---|---|
| Prolific, academic or non-profit | 33.3% | At least £6 or $8 per hour, with £9 or $12 recommended |
| Prolific, corporate | 42.8% | |
| Amazon Mechanical Turk | 20%, plus 20% for tasks with 10 or more assignments and 5% for Masters | Paid per task, with a minimum fee of $0.01 per assignment |
On a platform that pays per task, such as MTurk, set the reward from the time per item and your hourly rate. The breakdown shows what an annotator earns per item at your hourly rate, which is the reward to set for a one-item task, and a task of 20 items pays 20 times that.
Annotators per item and what one more costs
Annotation pay scales with the number of annotators per item, so going from three to five raises it by two thirds while training and adjudication do not change. The card for one more annotator per item shows that increment. Whether the extra annotator is worth it depends on how well the current ones agree, which the annotation power planner and the guide to how many annotators you need help decide before the budget is committed.
Related reading
The guide to running a study on Prolific and MTurk covers recruitment, quality control, and fair pay. Potato connects to both platforms and to any panel that passes a participant ID, with completion codes and attention-check screening, as described in crowdsourcing integration.