diff --git a/node/src/main/scala/com/wavesplatform/GenesisBlockGenerator.scala b/node/src/main/scala/com/wavesplatform/GenesisBlockGenerator.scala
index b3cce2edfe1..599247ee703 100644
--- a/node/src/main/scala/com/wavesplatform/GenesisBlockGenerator.scala
+++ b/node/src/main/scala/com/wavesplatform/GenesisBlockGenerator.scala
@@ -223,7 +223,12 @@ object GenesisBlockGenerator {
       def inverseCalculateDelay(balance: Long, hitRate: Double): Int =
         posCalculator match {
           case FairPoSCalculator(minBlockTime, _) =>
-            val z = (1 - Math.exp((settings.averageBlockDelay.toMillis - minBlockTime) / 70000.0)) * balance
+            val averageBlockDelay = settings.averageBlockDelay.toMillis
+            require(
+              averageBlockDelay > minBlockTime,
+              s"average-block-delay: ${averageBlockDelay}ms should be > min-block-time: ${minBlockTime}ms"
+            )
+            val z = (1 - Math.exp((averageBlockDelay - minBlockTime) / 70000.0)) * balance
             (5e17 * (Math.log(hitRate) / z)).toInt
           case NxtPoSCalculator =>
             (FairPoSCalculator.MaxHit * hitRate / settings.averageBlockDelay.toSeconds / balance).toInt