diff --git a/passes/cmds/splitfanout.cc b/passes/cmds/splitfanout.cc
index 2a7f5ad04..69c92b7cb 100644
--- a/passes/cmds/splitfanout.cc
+++ b/passes/cmds/splitfanout.cc
@@ -67,7 +67,7 @@ struct SplitfanoutWorker
 		}
 	}
 
-	int split(Cell *cell)
+	int split(Cell *cell, int fanoutlimit)
 	{
 		// Get output signal/port
 		SigSpec outsig;
@@ -93,8 +93,8 @@ struct SplitfanoutWorker
 			}
 		}
 
-		// Skip if output signal has only one user
-		if (GetSize(bit_users) <= 1)
+		// Skip if output signal has only one user or too many users
+		if (GetSize(bit_users) <= 1 || GetSize(bit_users) > fanoutlimit)
 			return 0;
 
 		// Iterate over bit users and create a new cell for each one
@@ -148,7 +148,7 @@ struct SplitfanoutPass : public Pass {
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
-		log("    splitfanout [selection]\n");
+		log("    splitfanout [options] [selection]\n");
 		log("\n");
 		log("This command copies selected cells with >1 fanout into cells with fanout 1. It\n");
 		log("is effectively the opposite of the opt_merge pass.\n");
@@ -156,16 +156,23 @@ struct SplitfanoutPass : public Pass {
 		log("This command operates only on cells with 1 output and no \"bit split\" on that\n");
 		log("output.\n");
 		log("\n");
+		log("    -fanoutlimit\n");
+		log("        fanout limit for splitfanout, beyond which no split (default: 10)\n");
+		log("\n");
 	}
 	void execute(std::vector<std::string> args, RTLIL::Design *design) override
 	{
+		int fanoutlimit = 10;
+
 		log_header(design, "Executing SPLITFANOUT pass (splitting up cells with >1 fanout into copies).\n");
 
 		size_t argidx;
 		for (argidx = 1; argidx < args.size(); argidx++)
 		{
-			// No options currently. When adding in the future make sure to update docstring with [options]
-			break;
+			if ((args[argidx] == "-fanoutlimit") && ((argidx + 1) < args.size())) {
+				fanoutlimit = std::stoi(args[++argidx]);
+				continue;
+			}
 		}
 		extra_args(args, argidx, design);
 
@@ -178,7 +185,7 @@ struct SplitfanoutPass : public Pass {
 				SplitfanoutWorker worker(module);
 				bool did_something = false;
 				for (auto cell : module->selected_cells()) {
-					int n = worker.split(cell);
+					int n = worker.split(cell, fanoutlimit);
 					did_something |= (n != 0);
 					count_split_pre += (n != 0);
 					count_split_post += n;
diff --git a/passes/opt/muxpack.cc b/passes/opt/muxpack.cc
index 3f7ee7221..fd8fcd3c4 100644
--- a/passes/opt/muxpack.cc
+++ b/passes/opt/muxpack.cc
@@ -344,6 +344,9 @@ struct MuxpackPass : public Pass {
 		log("    -splitfanout\n");
 		log("        run splitfanout pass first\n");
 		log("\n");
+		log("    -fanoutlimit\n");
+		log("        fanout limit for splitfanout, beyond which no split (default: 10)\n");
+		log("\n");
 		log("    -assume_excl\n");
 		log("        assume mutually exclusive constraint when packing (may result in inequivalence)\n");
 		log("\n");
@@ -352,6 +355,7 @@ struct MuxpackPass : public Pass {
 	{
 		bool splitfanout = false;
 		bool assume_excl = false;
+		int fanoutlimit = 10;
 
 		log_header(design, "Executing MUXPACK pass ($mux cell cascades to $pmux).\n");
 
@@ -362,6 +366,10 @@ struct MuxpackPass : public Pass {
 				splitfanout = true;
 				continue;
 			}
+			if ((args[argidx] == "-fanoutlimit") && ((argidx + 1) < args.size())) {
+				fanoutlimit = std::stoi(args[++argidx]);
+				continue;
+			}
 			if (args[argidx] == "-assume_excl") {
 				assume_excl = true;
 				continue;
@@ -371,7 +379,7 @@ struct MuxpackPass : public Pass {
 		extra_args(args, argidx, design);
 
 		if (splitfanout)
-			Pass::call(design, "splitfanout t:$mux t:$pmux");
+			Pass::call(design, stringf("splitfanout -fanoutlimit %d t:$mux t:$pmux", fanoutlimit));
 
 		int mux_count = 0;
 		int pmux_count = 0;
diff --git a/passes/opt/opt_balance_tree.cc b/passes/opt/opt_balance_tree.cc
index fc48974df..c608c280a 100644
--- a/passes/opt/opt_balance_tree.cc
+++ b/passes/opt/opt_balance_tree.cc
@@ -314,9 +314,13 @@ struct OptBalanceTreePass : public Pass {
 		log("    -splitfanout\n");
 		log("        run splitfanout pass first\n");
 		log("\n");
+		log("    -fanoutlimit\n");
+		log("        fanout limit for splitfanout, beyond which no split (default: 10)\n");
+		log("\n");
 	}
 	void execute(std::vector<std::string> args, RTLIL::Design *design) override {
 		bool splitfanout = false;
+		int fanoutlimit = 10;
 
 		log_header(design, "Executing OPT_BALANCE_TREE pass (cell cascades to trees).\n");
 
@@ -327,13 +331,17 @@ struct OptBalanceTreePass : public Pass {
 				splitfanout = true;
 				continue;
 			}
+			if ((args[argidx] == "-fanoutlimit") && ((argidx + 1) < args.size())) {
+				fanoutlimit = std::stoi(args[++argidx]);
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
 
 		// Run splitfanout pass first
 		if (splitfanout)
-			Pass::call(design, "splitfanout t:$and t:$or t:$xor t:$add t:$mul");
+			Pass::call(design, stringf("splitfanout -fanoutlimit %d t:$and t:$or t:$xor t:$add t:$mul", fanoutlimit));
 
 		// Count of all cells that were packed
 		dict<IdString, int> cell_count;