It sounds like there are three steps to your issue:
- Getting the duration in hours.
- Getting the total units picked.
- Dividing units picked by duration.
1. Getting the duration in hours
If you have a Duration field type, it stores the time internally in seconds. To convert seconds to hours, divide by 3600.
{Duration} / 3600
If you have two Date fields (which can also include times), you can use the DATETIME_DIFF([date1], [date2], ‘units’) formula to get the duration time. Use 'h' as the units to get the duration in hours.
DATETIME_DIF({EndDateTime}, {StartDateTime}, 'h')
If you have duration as a number of days or minutes (1 day = 1440 minutes), you can convert to hours
{DurationAsNumDays} * 24 if your duration is in days
{DurationAsNumMinutes} / 60 if your duration is in minutes
If the duration is a Single line text, you will need to parse it into a numeric value, which can be done, but you are better off converting it to a different field type.
2. Getting the total units picked
If your total {units picked} is already in a single numeric field in the same table, you are good to go.
If your {units picked} are in linked records, you will need a rollup with the SUM(values) aggregation formula.
3. Dividing units picked by duration
Depending on how your data is setup, you may be able put everything in one formula. However, if you need to use a rollup, you will need multiple fields: one for the linked records, one for the rollup, and another for the formula.
If your duration is a Duration field:
{Units Picked} / ({Duration} / 3600)
If you have fields for start and end date/times:
{Units Picked} / DATETIME_DIF({EndDateTime}, {StartDateTime}, 'h')
If your duration is a numeric field:
{Units Picked} / ({DurationAsNumMinutes} / 60) or
{Units Picked} / ({DurationAsNumDays} * 24)
Things get a little trickier if you need to rollup times as well as units picked, but hopefully this gives you enough to work with.
