diff --git a/frontend/src/lib/gif.ts b/frontend/src/lib/gif.ts
index c47ac41d..26d8bcc3 100644
--- a/frontend/src/lib/gif.ts
+++ b/frontend/src/lib/gif.ts
@@ -59,8 +59,7 @@ export const atMs = (s: number) => Math.round(s * 1000) / 1000;
 /** A range's length in whole milliseconds, between its ends as the request sends them: the length
  *  the server judges (gif.too_long), so a range the panel allows is never refused for its length,
  *  and none it refuses would have been made. */
-export const spanMs = (start: number, end: number) =>
-  Math.round(end * 1000) - Math.round(start * 1000);
+const spanMs = (start: number, end: number) => Math.round(end * 1000) - Math.round(start * 1000);
 
 /** A range's length to show beside a verdict: over the cap it is rounded up to the tenth, so a
  *  refused range never reads as one the cap allows ("0:30.0" for 30.03 s). */