diff --git a/src/abi/calldata/encoder.ts b/src/abi/calldata/encoder.ts
index 63a792d..431add8 100644
--- a/src/abi/calldata/encoder.ts
+++ b/src/abi/calldata/encoder.ts
@@ -87,7 +87,15 @@ function encodeImpl(to: number[], data: CalldataEncodable) {
   switch (typeof data) {
     case "number": {
       if (!Number.isInteger(data)) {
-        reportError("floats are not supported", data);
+        if (Number.isFinite(data) && Math.floor(data) === data) {
+          // Safe: float with no fractional part (e.g. 1.0 → 1)
+          encodeNum(to, BigInt(Math.trunc(data)));
+          return;
+        }
+        throw new Error(
+          `calldata encoding error: float value '${data}' is not supported. ` +
+          `Convert to an integer or pass as a string instead.`
+        );
       }
       encodeNum(to, BigInt(data));
       return;
diff --git a/tests/calldata-encoder.test.ts b/tests/calldata-encoder.test.ts
new file mode 100644
index 0000000..87c3e33
--- /dev/null
+++ b/tests/calldata-encoder.test.ts
@@ -0,0 +1,27 @@
+import { describe, it, expect } from "vitest";
+import { encode } from "../src/abi/calldata/encoder";
+import { decode } from "../src/abi/calldata/decoder";
+
+describe("calldata encoder - float handling", () => {
+  it("should encode integer numbers correctly", () => {
+    const encoded = encode(42);
+    const decoded = decode(encoded);
+    expect(decoded).toBe(42n);
+  });
+
+  it("should encode float with no fractional part as integer (e.g. 1.0)", () => {
+    const encoded = encode(1.0);
+    const decoded = decode(encoded);
+    expect(decoded).toBe(1n);
+  });
+
+  it("should throw descriptive error for true float values", () => {
+    expect(() => encode(1.5)).toThrow(
+      "calldata encoding error: float value '1.5' is not supported"
+    );
+  });
+
+  it("should throw descriptive error for NaN", () => {
+    expect(() => encode(NaN)).toThrow();
+  });
+});