Dune Sandworm Intercept Calculator
How long until the worm arrives? Can the riders mount before it passes?
why the worm's own length saves you 🖖
A sandworm is up to hundreds of meters of moving body, not a single point, so missing the head by a few seconds doesn't mean missing the ride — any exposed segment is still hookable. That's why the real deadline isn't when the worm arrives, it's when it finishes passing: arrival time plus body length divided by speed. It's the same forgiveness that lets you catch a moving train through any open door rather than sprinting for the exact front car — the longer or slower the target, the wider your effective catching window.
it's a race between two clocks 🖖
This tool doesn't reward raw speed — it compares two countdowns: how long until the worm's window shuts, and how long until your team is ready and in position. You win the moment the second one finishes first. The single term entirely in your hands is the setup delay, a flat number of seconds added no matter the distances or speeds, so trimming it is often the cheapest way to turn a miss into a catch.
a faster worm hurts more than you'd think 🖖
Your whole deadline is (D + L) / v — target distance plus body length, divided by worm speed. Because speed sits in the denominator, your available time drops as a hyperbola, not a straight line: at a slow crawl a few extra m/s barely register, but near a fast worm the same jump can halve your window. A worm only slightly quicker can flip a comfortable catch into a clean miss.
Example problems
- Clean intercept - With no setup delay, the Fremen team reaches the mount point at 50 seconds — well before the worm (arriving at 81.8s) even finishes passing at 87.3s. That's a comfortable 37-second boarding margin, plenty of time to plant the hooks.
- Late setup - Same speeds and distances as a clean intercept, but a 45-second setup delay pushes the team's arrival to 95 seconds — 7.7 seconds after the worm's tail has already cleared the mount point. The worm doesn't get faster; the team just runs out of runway.
- Fast worm - At 45 m/s this worm covers 1,500m in just 33.3 seconds, and even its extra-long 200m body only buys 4.4 seconds of grace before the tail clears at 37.8s — nowhere near enough for a 50-second Fremen approach. Some worms are simply too fast to catch on foot.