How long would a 1 GB file take?
Using decimal gigabytes, a 1 GB file contains 8,000 megabits. Divide that by the upload speed in Mbps: at 10 Mbps it takes 800 seconds, or 13 minutes 20 seconds; at 20 Mbps, 6 minutes 40 seconds; at 40 Mbps, 3 minutes 20 seconds. These are calculated minimum times at a steady rate, not promised Starlink speeds. Overhead, changing speeds and the receiving service can all make a real transfer take longer.
If calls suffer during backups
Pause a non-urgent upload or cloud backup and repeat the call. If the problem disappears, schedule that work outside your call times or check whether the backup application lets you limit its upload rate. Repeat the test under normal household use before deciding that you need another broadband plan.
Compare upload as well as download
Look for the upload figure on the exact plans available at your address. If you send a large folder every working day, use its size to compare likely waiting times. A higher download headline says little about that task. Test from a wired connection or beside the router so poor Wi-Fi does not dominate the result.
Send a correction if a source has changed or something needs updating.