diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index 4ded574f0..e12a89e20 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -163,7 +163,8 @@ def compute_randao_mix(state: BeaconState, randao_reveal: BLSSignature) -> Bytes
 
 ```python
 def compute_time_at_slot(state: BeaconState, slot: Slot) -> uint64:
-    return uint64(state.genesis_time + slot * SECONDS_PER_SLOT)
+    slots_since_genesis = slot - GENESIS_SLOT
+    return uint64(state.genesis_time + slots_since_genesis * SECONDS_PER_SLOT)
 ```
 
 ### Beacon state accessors