Premium proration calculator: what is the premium for a partial month?
Enter the monthly premium, the days in the month and the date coverage starts or ends to see a daily prorated premium. Built for HR and finance teams checking carrier bills.
Prorate a premium for a partial month.
Most carriers bill whole months, so use this to compare. The result updates as you type.
Your estimate
An illustration of daily proration. Your carrier billing rules and plan terms control what is owed.
Do carriers prorate premiums?
Some do and many do not. A common approach is to bill a full month for a person covered on the first of the month and no premium for a person whose coverage ends before it. Others bill by the day. The rule is in the carrier agreement, so check it before you decide how to handle a mid-month hire or termination.
What should employers decide?
Decide when new hire coverage starts, such as the date of hire or the first of the following month, and when coverage ends after termination. Apply the rule the same way for everyone and write it in the plan document. Then check each carrier bill against it, since billing errors for partial months are common.
Common questions
Why does the last day of coverage matter?
Coverage that ends at the end of the month needs no proration. A mid-month end date can create a partial month or a full month charge, depending on the carrier.
Should employees pay for the partial month?
That is your policy decision. Many employers deduct a full month or none. Apply it consistently.
What about COBRA?
COBRA begins when active coverage ends. The dates should line up so there is no gap. Our COBRA end date calculator helps with the dates.
How do I avoid billing errors?
Reconcile each carrier bill against your enrollment records every month. A benefits platform that feeds the carrier can lower errors.
Talk to us about billing and administration
Book a 30-minute call and we will look at your carrier bills, your enrollment process and the fixes that fit. Visit us at 41000 Woodward Avenue, Suite 350 East, Bloomfield Hills, MI 48304, or call 248.370.8853.
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