Methods and apparatus are disclosed to correct hash keys. An example method involves accessing a first metered hash key and first reference metadata associated with the first metered hash key. Accessing second reference metadata associated with a second hash key adjacent to the first metered hash key. Determining if the first metered hash key is unexpected. When the first metered hash key is unexpected, generating an error level using a first bitwise comparison of the first metered hash key and the second hash key. Determining if the error level satisfies a threshold. When the error level satisfies the threshold, storing the second hash key as the first metered hash key.