Reversible vs Non-Reversible Laytime

Reversible or non-reversible laytime decides whether load and discharge time are pooled or counted separately — and it can change the demurrage result by tens of thousands of dollars.

Whether laytime is reversible or non-reversible decides how the allowed time is applied across a voyage — and it can change the demurrage result by tens of thousands of dollars. Here is the difference.

Non-reversible laytime

Load and discharge are counted separately, each against its own allowance. Time saved at the load port cannot offset time lost at the discharge port. You run two calculations and add the results.

Reversible laytime

Load and discharge time are pooled into one combined allowance. The charterer is judged on the total time used across both ends versus the total time allowed. Time saved loading can absorb time lost discharging — which usually works in the charterer's favour.

A worked example

Say the allowance is 36 hours at each end (72 hours total). The vessel uses 24 hours loading and 54 hours discharging.

• Non-reversible: loading is 12 hours under (no demurrage, and often no despatch on tankers); discharging is 18 hours over → 18 hours on demurrage.
• Reversible: total used 78 hours vs 72 allowed → only 6 hours on demurrage.

How to tell which applies

It is set in the charter party — look for the word "reversible" against the laytime terms. Applying the wrong basis is one of the most common errors in owners' laytime statements, so it is always worth checking when you review a claim. See also how to calculate laytime.