# Learning Curve Calculator

Repetetive Learning Calculator
Equation:   Wright
Crawford
Time Required to
Produce 1st Unit

Learning %    %
Total Units

In manufacturing the learning curve or experience curve represents how processes become more efficient over time as more and more units are produced. The learning curve coefficient or learning rate is the reduction in cost for every doubling in production.

For example, if the amount of time needed to manufacture a certain number of units decreases by 20% every time the number of units produced doubles, then the learning curve percent is 80%.

There are two models used to figure the total amount of time needed to produce X number of units, given the learning rate and amount of time required to create the first specimen; one is the Wright Model and the other is the Crawford Model. The equations are similar. If K is the amount of time needed to produce the first unit and the learning curve factor is b (expressed as a decimal and not a percent) then the amount of time needed to produce x units is given by

Total Time = Kx1+log2b        (Wright Formula)

Total Time = Σ Kilog2b , for 1 ≤ i ≤ x        (Crawford Formula)

You can use the calculator above to calculate the total time required for a repetetive process with given values of K, b, and x. (For the calculator, enter b as a percent, not a decimal.) If you are unsure about the learning curve percent, here are some rough guidelines devised by NASA:

If the process requires 75% human labor and 25% machine labor, the learning percent is about 80%.

If the process requires human labor and machine labor in equal measure, the learning percent is about 85%.

If 75% of the process is done by machine and only 25% by hand, the learning percent is around 90%.

The closer the learning percent is to 100%, the more negligible the effects of experience. Processes that involve more of a human assembly component have lower learning curve percents.