diff --git a/qupulse/utils/__init__.py b/qupulse/utils/__init__.py
index 3ad983cc..fa571537 100644
--- a/qupulse/utils/__init__.py
+++ b/qupulse/utils/__init__.py
@@ -131,7 +131,7 @@ def forced_hash(obj) -> int:
 
 
 def to_next_multiple(sample_rate: ExpressionLike, quantum: int,
-                     min_quanta: Optional[int] = None) -> Callable[[ExpressionLike],ExpressionScalar]:
+                     min_quanta: Optional[int] = None) -> Callable[[ExpressionScalar], ExpressionLike]:
     """Construct a helper function to expand a duration to one corresponding to
     valid sample multiples according to the arguments given.
     Useful e.g. for PulseTemplate.pad_to's 'to_new_duration'-argument.
@@ -141,33 +141,34 @@ def to_next_multiple(sample_rate: ExpressionLike, quantum: int,
         quantum: number of samples to whose next integer multiple the duration shall be rounded up to.
         min_quanta: number of multiples of quantum not to fall short of.
     Returns:
-        A function that takes a duration (ExpressionLike) as input, and returns
+        A function that takes a duration as input, and returns
         a duration rounded up to the next valid samples count in given sample rate.
         The function returns 0 if duration==0, <0 is not checked if min_quanta is None.
 
     """
     sample_rate = ExpressionScalar(sample_rate)
+
     #is it more efficient to omit the Max call if not necessary?
     if min_quanta is None:
         #double negative for ceil division.
         return lambda duration: -(-(duration*sample_rate)//quantum) * (quantum/sample_rate)
     else:
-        qI  = sp.Integer(quantum)
-        k   = qI / sample_rate  # factor to go from #quanta -> duration
-        mqI = sp.Integer(min_quanta)
-                
-        def _build_sym(d):
-            u  = d*sample_rate/qI                # "duration in quanta" (real)
-            ce = sp.ceiling(u)          # number of quanta after rounding up
-
-            # Enforce: 0 if d <= 0; else at least mqI quanta.
-            # max(mqI, ceil(u))  <=>  mqI if u <= mqI, else ceil(u)
-            # do not evaluate right now because parameters could still be variable,
-            # then it's just overhead.
-            return sp.Piecewise(
-                (0,  sp.Le(d, 0)),
-                (k*mqI, sp.Le(u, mqI)),
-                (k*ce, True)
-            , evaluate=False)
-        
-        return lambda duration: ExpressionScalar(_build_sym(duration))
\ No newline at end of file
+        # work with sympy
+        sample_rate = sample_rate.sympified_expression
+        duration_per_quantum = sp.Integer(quantum) / sample_rate
+        minimal_duration = duration_per_quantum * min_quanta
+
+        def build_next_multiple(duration: ExpressionScalar) -> ExpressionLike:
+            duration = sp.sympify(duration)
+            n_quanta = sp.ceiling(duration / duration_per_quantum)
+            rounded_up_duration = n_quanta * duration_per_quantum
+
+            next_multiple_sp = sp.Piecewise(
+                (0, sp.Le(n_quanta, 0)),
+                (minimal_duration, sp.Le(n_quanta, min_quanta)),
+                (rounded_up_duration, True),
+                evaluate=False,
+            )
+            return ExpressionScalar(next_multiple_sp)
+
+        return build_next_multiple