When to leave for DEN.

Every row is editable: tap the boarding time or any duration and the whole plan recomputes backward. The first travel row — drive, ride, or train — is your leave-by time; the top row is when the trip actually starts.

The 40-minute drive is a typical run from Denver without traffic. Check the real drive to DEN at the hour you’ll actually leave, then put that number in.

Getting to Denver International

The A-Line commuter train runs from Union Station to the terminal in about 37 minutes on a schedule, which makes it the most predictable way in. Driving means I-70 or E-470 plus a shuttle from the economy lots.

The moving targets — today’s security waits, parking availability, terminal maps — live on the official DEN site. This page covers the part that doesn’t change: the backward arithmetic from boarding.

The part the airport can't see

Every airport tells you when to arrive. None of them tell you when to get in the shower, and that's the number that decides whether the morning is calm or a scramble. The plan above keeps subtracting past the drive — through packing, through getting ready — until it lands on a start time you can actually act on.

That's what Ready Time does for the whole trip: set boarding as the deadline, list the real steps, and get an alert when each one is due to start. It can even pick the flight up from your calendar.

How early should I get to DEN?

The standard advice is the right advice here: be at the airport two hours before a domestic flight and three before an international one. At an airport this size those numbers are a floor — they assume the lines are merely normal. DEN sits about 25 miles from downtown on the plains — the drive is long on a good day, and there is no quick version of it.

How long is security at DEN?

Denver's checkpoint lines are famously variable, and every gate requires the train from the terminal out to concourses A, B, or C, which adds a leg after security that first-time flyers don't budget. Whatever wait you've heard about, treat the 30-minute security row in the plan above as a default to edit, not a promise: TSA PreCheck reliably shrinks it, and a checked bag reliably grows the step before it.

Does flying international out of DEN change this?

Mostly at the front of the chain. International check-in usually means the airline desk rather than a kiosk — documents get checked, and counters often close an hour before departure — and boarding opens earlier relative to takeoff. Choose “check-in desk” above the plan, give that row room, and take the boarding time from your boarding pass instead of guessing backward from departure. The same choice covers anyone the kiosk can't help: lap infants, unaccompanied minors, oversized bags.

When should I leave for DEN?

Work backward from boarding, in order: time at the gate, the walk, security, bag drop, parking, then the drive — 40 minutes in the default plan, which you should replace with your route at the hour you'll actually drive it. The calculator above runs the subtraction; the leave-by moment is the first travel row — "Drive to DEN" in the default plan.

Can I get an alert when it's time to leave?

That's Ready Time's whole job. Build this plan once in the app and every step gets its own notification at its start time — start packing, leave now, you're at security's mercy from here. It can detect flights from your calendar, and the alerts carry the countdown to boarding.

Not flying? The generic leave time calculator does the same math for any appointment, and the wake-up time calculator runs it all the way back to the alarm.