Enter the total hours worked and the number of parts produced into the calculator to determine the hours per part.
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Hours Per Part Formula
The calculator uses three related formulas depending on which mode you select.
Actual run mode:
HPP = T / N
Convert mode (rate and cycle time are reciprocals):
HPP = 1 / R
Plan mode:
T = HPP * N N = T / HPP
- HPP = hours per part (cycle time in hours)
- T = production run time, in hours
- N = number of parts produced
- R = production rate in parts per hour
The Actual run tab divides run time by parts to give you the realized cycle time, including any small slowdowns inside the run. The Convert tab takes a known rate or cycle time in any common unit and restates it as hours per part along with all the reciprocals. The Plan tab solves the same equation for whichever variable you do not know: enter a target HPP and a part count to get required run time, or enter a target HPP and an available run window to get the part count you can complete.
Typical Cycle Times and Quick Conversions
Use the first table to sanity-check whether your hours-per-part value lands in a normal range for the type of work. Use the second table to convert between the common ways cycle time and rate get reported on the floor.
| Process type | Typical hours per part | Equivalent rate |
|---|---|---|
| High-speed stamping | 0.0001 to 0.001 | 1,000 to 10,000 / hr |
| Injection molding (small part) | 0.003 to 0.017 | 60 to 360 / hr |
| CNC machining (small) | 0.05 to 0.5 | 2 to 20 / hr |
| Manual assembly station | 0.02 to 0.25 | 4 to 50 / hr |
| CNC machining (medium) | 0.5 to 3 | 0.33 to 2 / hr |
| Welded fabrication | 1 to 8 | 0.13 to 1 / hr |
| Industrial 3D printing | 2 to 24 | 0.04 to 0.5 / hr |
| Hours per part | Minutes per part | Seconds per part | Parts per hour |
|---|---|---|---|
| 0.0028 | 0.17 | 10 | 360 |
| 0.0083 | 0.5 | 30 | 120 |
| 0.0167 | 1 | 60 | 60 |
| 0.05 | 3 | 180 | 20 |
| 0.25 | 15 | 900 | 4 |
| 0.5 | 30 | 1,800 | 2 |
| 1 | 60 | 3,600 | 1 |
| 4 | 240 | 14,400 | 0.25 |
Worked Examples
Example 1: Actual run. A machining cell ran for 7.5 hours and produced 450 parts (good plus scrap). HPP = 7.5 / 450 = 0.0167 hr/part. That converts to 1 minute per part, or 60 parts per hour.
Example 2: Plan a job. You need 300 parts and the routing lists 0.125 hr/part. Required run time = 0.125 × 300 = 37.5 hours, which is 4.7 eight-hour shifts of pure run time before you add changeover and breaks.
FAQ
Should I include scrap in the part count? Yes when measuring actual cycle time, because every part consumes machine time. Use only good parts when reporting yield-adjusted rates or calculating cost per good part.
Should run time include downtime? No. Use active production run time so the result reflects the cycle. Including downtime gives you a different metric closer to throughput or OEE-adjusted rate.
How does this differ from takt time? Hours per part is your actual or target cycle time. Takt time is available time divided by customer demand. They match only when you produce exactly to demand with no buffer.
Why is parts per hour the reciprocal of hours per part? Rate and cycle time describe the same process from opposite directions. If one part takes 0.25 hours, then in one hour you complete 1 / 0.25 = 4 parts.