diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c21aa4f..1d1298a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,13 +1,20 @@
 # Contributing
-Thank you for thinking about contributing to this project. This document will help you to get started.
+
+Thank you for thinking about contributing to this project. This document will
+help you to get started.
 
 ## Adding a feature
-If you'd like to add a feature to Avatar (or modify its existing behaviour), please start by [creating an issue][create_issue] so we can discuss it.
-Don't go straight to a pull request in case it's something I don't wish to accept; I don't want to waste your time.
+
+If you'd like to add a feature to Avatar (or modify its existing behaviour),
+please start by [creating an issue][create_issue] so we can discuss it. Don't go
+straight to a pull request in case it's something I don't wish to accept; I
+don't want to waste your time.
 
 ## Fixing a bug
-If you've found a bug, please start by [creating an issue][create_issue]. If you'd like to [make a pull request][create_pr] for the fix once I've confirmed it's a bug in Avatar, that would be great.
+
+If you've found a bug, please start by [creating an issue][create_issue]. If
+you'd like to [make a pull request][create_pr] for the fix once I've confirmed
+it's a bug in Avatar, that would be great.
 
 [create_issue]: https://github.com/monooso/avatar/issues/new
 [create_pr]: https://github.com/monooso/avatar/compare
-
diff --git a/README.md b/README.md
index 3c8792e..044ada3 100644
--- a/README.md
+++ b/README.md
@@ -9,10 +9,7 @@ avatars based on usernames or ids.
 ## Usage
 
 ```typescript
-import {
-  generatePng,
-  generateSvg,
-} from "https://deno.land/x/avatar@v1.3.0/mod.ts";
+import { generatePng, generateSvg } from "https://deno.land/x/avatar/mod.ts";
 
 // Generate an SVG avatar with the default options.
 let avatar = await generateSvg("jimbob");
@@ -31,6 +28,7 @@ avatar = await generatePng("cleetus", { radius: 20, size: 256 });
 ```
 
 ## License
+
 Avatar is open source software, released under [the MIT license](./LICENSE.txt).
 
 ## Credits
diff --git a/lib/options.ts b/lib/options.ts
index 25926b5..9754722 100644
--- a/lib/options.ts
+++ b/lib/options.ts
@@ -1,18 +1,21 @@
 import { z } from "https://deno.land/x/zod@v3.22.4/mod.ts";
 
+const defaults = { radius: 0, size: 64 };
+
 const validator = z.object({
-  radius: z.number().int().min(0).default(0),
-  size: z.number().int().min(1).default(64),
+  radius: z.number().int().min(0).default(defaults.radius),
+  size: z.number().int().min(1).default(defaults.size),
 });
 
-type Options = z.input<typeof validator>;
+type InputOptions = z.input<typeof validator>;
+type OutputOptions = z.output<typeof validator>;
 
 /**
  * Validates and normalizes the given options. Raises if validation fails.
  */
-function validate(opts: Options): Options {
+function validate(opts: InputOptions): OutputOptions {
   return validator.parse(opts);
 }
 
-export { validate };
-export type { Options };
+export { defaults, validate };
+export type { InputOptions, OutputOptions };
diff --git a/lib/png.ts b/lib/png.ts
index 320838d..013a586 100644
--- a/lib/png.ts
+++ b/lib/png.ts
@@ -1,12 +1,15 @@
 import { resvg } from "../deps.ts";
 import * as svg from "./svg.ts";
-import type { Options } from "./options.ts";
+import type { InputOptions } from "./options.ts";
 
 /**
  * Generates a reproducible PNG image from a given seed.
  * Renders the image as an SVG, and then converts it to a PNG using resvg.
  */
-async function generate(seed: string, opts?: Options): Promise<Uint8Array> {
+async function generate(
+  seed: string,
+  opts?: InputOptions,
+): Promise<Uint8Array> {
   const svgString = await svg.generate(seed, opts);
   return resvg.render(svgString);
 }
diff --git a/lib/svg.ts b/lib/svg.ts
index f8db26d..56d1cd8 100644
--- a/lib/svg.ts
+++ b/lib/svg.ts
@@ -1,19 +1,20 @@
 import * as keys from "./keys.ts";
 import miniavs from "./collections/miniavs/index.ts";
-import * as options from "./options.ts";
-import type { Options } from "./options.ts";
+import { defaults, validate } from "./options.ts";
+import type { InputOptions } from "./options.ts";
 
 /**
  * Generates a reproducible SVG image for the given seed.
  */
-async function generate(seed: string, opts?: Options): Promise<string> {
+async function generate(seed: string, opts?: InputOptions): Promise<string> {
   const key = await keys.generate(seed);
-  opts = options.validate(opts || {});
+  const { radius, size } = validate(opts || {});
+  const scaledRadius = (defaults.size / size) * radius;
 
   return `
-<svg width="${opts.size}" height="${opts.size}" viewBox="0 0 64 64" fill="none" version="1.1" xmlns="http://www.w3.org/2000/svg">
+<svg width="${size}" height="${size}" viewBox="0 0 64 64" fill="none" version="1.1" xmlns="http://www.w3.org/2000/svg">
   <clipPath id="avatarShape">
-    <rect x="0" y="0" width="64" height="64" rx="${opts.radius}" ry="${opts.radius}" />
+    <rect x="0" y="0" width="64" height="64" rx="${scaledRadius}" ry="${scaledRadius}" />
   </clipPath>
 
   <g clip-path="url(#avatarShape)">
diff --git a/tests/lib/svg_test.ts b/tests/lib/svg_test.ts
index f5dfdeb..9ac107d 100644
--- a/tests/lib/svg_test.ts
+++ b/tests/lib/svg_test.ts
@@ -53,6 +53,14 @@ Deno.test("svg", async (t) => {
     },
   );
 
+  await t.step("it treats the radius as an absolute value", async () => {
+    // 64 is the default size, 256 is the given size, 10 is the desired radius.
+    const radius = (64 / 256) * 10;
+    const regex = new RegExp(`<rect [^>]+ rx="${radius}" ry="${radius}"`, "is");
+    const svg = (await generate("test", { size: 256, radius: 10 })).trim();
+    assert(regex.test(svg));
+  });
+
   // keys_test.ts covers the seed validation, this is just a sanity check.
   await t.step("it raises if the seed is invalid", () => {
     assertRejects(() => generate(1));