diff --git a/contracts/Periods.sol b/contracts/Periods.sol
index 189fb02..817d09c 100644
--- a/contracts/Periods.sol
+++ b/contracts/Periods.sol
@@ -29,7 +29,7 @@ contract Periods {
   }
 
   function _nextPeriod(Period period) internal pure returns (Period) {
-    return Period.wrap(Period.unwrap(period) + 1);
+    return Period.wrap(Period.unwrap(period));
   }
 
   function _periodStart(Period period) internal view returns (Timestamp) {