diff --git a/README.md b/README.md
index ad81946..2cdd21c 100644
--- a/README.md
+++ b/README.md
@@ -7,13 +7,26 @@
 ```js
 import {mergeCidr, excludeCidr, expandCidr, overlapCidr, containsCidr, normalizeCidr, parseCidr} from "cidr-tools";
 
-mergeCidr(["1.0.0.0/24", "1.0.1.0/24"]); //=> ["1.0.0.0/23"]
-excludeCidr(["::1/127"], "::1/128") //=> ["::/128"]
-expandCidr(["2001:db8::/126"]) //=> ["2001:db8::", "2001:db8::1", "2001:db8::2", "2001:db8::3"]
-overlapCidr("1.0.0.0/24", "1.0.0.128/25") //=> true
-containsCidr(["1.0.0.0/24", "2.0.0.0/24"], "1.0.0.1") //=> true
-normalizeCidr("::ffff/64") //=> "::/64"
-parseCidr("::/64"); // => {cidr: "::/64", version: 6, prefix: "64", start: 0n, end: 18446744073709551615n}
+mergeCidr(["1.0.0.0/24", "1.0.1.0/24"]);
+//=> ["1.0.0.0/23"]
+
+excludeCidr(["::1/127"], "::1/128");
+//=> ["::/128"]
+
+Array.from(expandCidr(["2001:db8::/126"]));
+//=> ["2001:db8::", "2001:db8::1", "2001:db8::2", "2001:db8::3"]
+
+overlapCidr("1.0.0.0/24", "1.0.0.128/25");
+//=> true
+
+containsCidr(["1.0.0.0/24", "2.0.0.0/24"], "1.0.0.1");
+//=> true
+
+normalizeCidr("::ffff/64");
+//=> "::/64"
+
+parseCidr("::/64");
+// => {cidr: "::/64", version: 6, prefix: "64", start: 0n, end: 18446744073709551615n}
 ```
 
 ## API
@@ -41,7 +54,7 @@ Returns an array of merged remaining networks.
 
 - `networks` *String* or *Array*: One or more CIDR or IP addresses.
 
-Returns an array of individual IPs contained in the networks.
+Returns a generator for individual IPs contained in the networks. Be aware that asking for expansions of big networks can result in long runtimes and possibly high memory usage. One million IPs takes about 2 seconds on modern hardware.
 
 ### overlapCidr(networksA, networksB)
 
diff --git a/index.test.ts b/index.test.ts
index 20a0db9..1fc2ab6 100644
--- a/index.test.ts
+++ b/index.test.ts
@@ -50,10 +50,10 @@ test("excludeCidr", () => {
 });
 
 test("expandCidr", () => {
-  expect(expandCidr(["1.2.3.0/31"])).toEqual(["1.2.3.0", "1.2.3.1"]);
-  expect(expandCidr(["1::/126"])).toEqual(["1::", "1::1", "1::2", "1::3"]);
-  expect(expandCidr(["2008:db1::/127"])).toEqual(["2008:db1::", "2008:db1::1"]);
-  expect(expandCidr("2008:db1::/127")).toEqual(["2008:db1::", "2008:db1::1"]);
+  expect(Array.from(expandCidr(["1.2.3.0/31"]))).toEqual(["1.2.3.0", "1.2.3.1"]);
+  expect(Array.from(expandCidr(["1::/126"]))).toEqual(["1::", "1::1", "1::2", "1::3"]);
+  expect(Array.from(expandCidr(["2008:db1::/127"]))).toEqual(["2008:db1::", "2008:db1::1"]);
+  expect(Array.from(expandCidr("2008:db1::/127"))).toEqual(["2008:db1::", "2008:db1::1"]);
 });
 
 test("overlapCidr", () => {
diff --git a/index.ts b/index.ts
index f833cac..be0ae82 100644
--- a/index.ts
+++ b/index.ts
@@ -382,17 +382,15 @@ export function excludeCidr(base: Networks, excl: Networks): Network[] {
   return bases[4].concat(bases[6]).sort(compare);
 }
 
-export function expandCidr(nets: Networks): Network[] {
+export function* expandCidr(nets: Networks): Generator<Network> {
   const arr: Network[] = uniq(Array.isArray(nets) ? nets : [nets]);
-  const ips: Network[] = [];
 
   for (const net of mergeCidr(arr)) {
     const {start, end, version} = parseCidr(net);
     for (let number = start; number <= end; number++) {
-      ips.push(stringifyIp({number, version}));
+      yield normalizeCidr(stringifyIp({number, version}));
     }
   }
-  return ips.map(ip => normalizeCidr(ip));
 }
 
 export function overlapCidr(a: Networks, b: Networks): boolean {