Calculate a battery pro rata warranty credit: enter the price, warranty months and battery age, plus any free replacement period, to see your discount.

Free replacement period
Months of full free replacement before pro rata starts (the FR in FR + PR). Leave blank if none.

Battery Pro Rata Formula

The following formula and example show a simple monthly pro rata allocation.

BPR = BP / W

Variables:

  • BPR is the Battery Pro Rata ($/month of warranty)
  • BP is the total battery price ($) 
  • W is the warranty length (months) 

To calculate a battery pro rata, divide the battery price by the total warranty length. Select the desired result explicitly: monthly rate, battery price or warranty length.

The remaining-credit modes use credit = original price × max(0, 1 − battery age / coverage period). Remaining months are max(0, coverage − age). For example, $300 over 60 months at age 24 months gives $180 modeled credit and 36 months remaining. At and after expiry, credit and remaining months are zero. Some inverse inputs do not determine a unique answer; the calculator explains these cases.

This is a straight-line estimate, not a warranty entitlement. Actual eligibility, free-replacement periods, price basis, taxes and fees follow the applicable written policy. Product and purchase-date rules vary; consult the seller or manufacturer’s warranty lookup.

How to Calculate Battery Pro Rata?

The following steps outline how to calculate the Battery Pro Rata.

  1. First, determine the total battery price ($). 
  2. Next, determine the warranty length (months). 
  3. Next, gather the formula from above: BPR = BP / W.
  4. Finally, calculate the Battery Pro Rata.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total battery price ($) = 300

warranty length (months) = 6

BPR = BP / W = $300 ÷ 6 = $50 per month.