The distance on the completion is obtained by extending the distance on the original space, by uniform continuity.
The new distance is uniformly continuous.
The new distance is an extension of the original distance.
Elements of the uniformity (defined generally for completions) can be characterized in terms of the distance.
If two points are at distance 0, then they coincide.
Metric space structure on the completion of a metric space.
The embedding of a metric space in its completion is an isometry.