diff --git a/CHANGES.md b/CHANGES.md
index 9c38282..687d622 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,7 @@
 # Changes
 
 ## Unreleased
+- Add splitBill(items, people) to split the taxed total between people.
 
 ## 1.2.0
 - total() rounds through roundCents().
diff --git a/src/lib/cart.js b/src/lib/cart.js
index 385fd69..2065158 100644
--- a/src/lib/cart.js
+++ b/src/lib/cart.js
@@ -8,3 +8,18 @@ export function subtotal(items) {
 export function total(items) {
   return roundCents(subtotal(items) * (1 + TAX_RATE));
 }
+
+// `people` is a head count or an array of people. Everyone pays an equal
+// rounded share; the last person absorbs the rounding remainder so the
+// shares always add up to total(items).
+export function splitBill(items, people) {
+  const count = Array.isArray(people) ? people.length : people;
+  if (!Number.isInteger(count) || count < 1) {
+    throw new RangeError('splitBill needs at least one person');
+  }
+  const billTotal = total(items);
+  const share = roundCents(billTotal / count);
+  const shares = new Array(count - 1).fill(share);
+  shares.push(roundCents(billTotal - share * (count - 1)));
+  return shares;
+}
diff --git a/tests/lib/cart.test.js b/tests/lib/cart.test.js
index 7a9eab3..c7c1bc7 100644
--- a/tests/lib/cart.test.js
+++ b/tests/lib/cart.test.js
@@ -1,6 +1,7 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
-import { subtotal, total } from '../../src/lib/cart.js';
+import { subtotal, total, splitBill } from '../../src/lib/cart.js';
+import { roundCents } from '../../src/lib/money.js';
 
 const items = [{ price: 10, qty: 2 }, { price: 5, qty: 1 }];
 
@@ -11,3 +12,27 @@ test('subtotal adds price times quantity', () => {
 test('total applies tax and rounds to cents', () => {
   assert.equal(total(items), 27);
 });
+
+test('splitBill splits the taxed total evenly', () => {
+  assert.deepEqual(splitBill(items, 2), [13.5, 13.5]);
+});
+
+test('splitBill shares always add up to the total', () => {
+  const shares = splitBill([{ price: 10, qty: 1 }], 3); // total 10.80
+  assert.equal(shares.length, 3);
+  assert.equal(roundCents(shares.reduce((a, b) => a + b, 0)), total([{ price: 10, qty: 1 }]));
+  const odd = splitBill([{ price: 1, qty: 1 }], 3); // total 1.08 -> 0.36 each
+  assert.deepEqual(odd, [0.36, 0.36, 0.36]);
+  const uneven = splitBill([{ price: 0.1, qty: 1 }], 3); // total 0.11
+  assert.equal(roundCents(uneven.reduce((a, b) => a + b, 0)), 0.11);
+});
+
+test('splitBill accepts a list of people', () => {
+  assert.deepEqual(splitBill(items, ['a', 'b']), [13.5, 13.5]);
+});
+
+test('splitBill rejects an invalid number of people', () => {
+  assert.throws(() => splitBill(items, 0));
+  assert.throws(() => splitBill(items, []));
+  assert.throws(() => splitBill(items, 1.5));
+});