diff --git a/src/parse.ts b/src/parse.ts
index b67cfa3..e811875 100644
--- a/src/parse.ts
+++ b/src/parse.ts
@@ -29,16 +29,19 @@ export function readJsonBodyOption<T = unknown>(
 }
 
 export function parseIntOption(value: string, name: string): number {
-  const parsed = Number.parseInt(value, 10)
-  if (Number.isNaN(parsed)) {
+  const parsed = Number(value)
+  if (!/^[+-]?\d+$/.test(value) || !Number.isFinite(parsed)) {
     throw new Error(`Invalid value for ${name}: "${value}" is not an integer`)
   }
   return parsed
 }
 
 export function parseFloatOption(value: string, name: string): number {
-  const parsed = Number.parseFloat(value)
-  if (Number.isNaN(parsed)) {
+  const parsed = Number(value)
+  if (
+    !/^[+-]?(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?$/.test(value) ||
+    !Number.isFinite(parsed)
+  ) {
     throw new Error(`Invalid value for ${name}: "${value}" is not a number`)
   }
   return parsed
diff --git a/test/parse.test.ts b/test/parse.test.ts
index 7236df5..ed1073d 100644
--- a/test/parse.test.ts
+++ b/test/parse.test.ts
@@ -27,6 +27,17 @@ describe("parseIntOption", () => {
       'Invalid value for --limit: "" is not an integer',
     )
   })
+
+  it.each([
+    "10foo",
+    "1.9",
+    "1e2",
+    "0x10",
+  ])('throws when "%s" is not entirely an integer', value => {
+    expect(() => parseIntOption(value, "--limit")).toThrow(
+      `Invalid value for --limit: "${value}" is not an integer`,
+    )
+  })
 })
 
 describe("parseFloatOption", () => {
@@ -34,6 +45,9 @@ describe("parseFloatOption", () => {
     expect(parseFloatOption("0.5", "--slippage")).toBe(0.5)
     expect(parseFloatOption("1", "--slippage")).toBe(1)
     expect(parseFloatOption("0.01", "--slippage")).toBe(0.01)
+    expect(parseFloatOption(".5", "--slippage")).toBe(0.5)
+    expect(parseFloatOption("1.", "--slippage")).toBe(1)
+    expect(parseFloatOption("1e-2", "--slippage")).toBe(0.01)
   })
 
   it("throws on non-numeric strings", () => {
@@ -47,6 +61,17 @@ describe("parseFloatOption", () => {
       'Invalid value for --slippage: "" is not a number',
     )
   })
+
+  it.each([
+    "0.5oops",
+    "0.01%",
+    "Infinity",
+    "1e309",
+  ])('throws when "%s" is not an entirely finite number', value => {
+    expect(() => parseFloatOption(value, "--slippage")).toThrow(
+      `Invalid value for --slippage: "${value}" is not a number`,
+    )
+  })
 })
 
 describe("readJsonBodyOption", () => {