Gain per mile, and why it matters
We've talked about mileage lying and how to read a profile. Today we're doing the math that ties it together: gain per mile.
Here's the number I actually care about. Not total mileage, not total elevation gain, but the two divided together. Take the elevation gain in feet, divide by the miles, and you get a rate. That rate tells you what kind of hike you're actually signing up for.
Why the rate matters more than either number alone
A trail with 1,000 feet of gain over 5 miles is a pretty easy morning. That's 200 feet per mile. Gentle grade, steady walk, you could hold a conversation the whole way.
A trail with 1,000 feet of gain over 2 miles is a completely different hike. That's 500 feet per mile, and you'll feel it in your legs and your lungs both. Same total gain, same trailhead sign maybe, totally different day.
I didn't understand this for a long time. I told you last lesson about the four-mile hike that felt like ten. That's the gain-per-mile problem exactly. I looked at "four miles" and thought "short hike, no problem." I didn't check what the gain was doing across those four miles. Turned out almost all of it happened in the first mile and a half. Steep, relentless, no letup. If I'd done the division ahead of time I'd have known what I was walking into.
How to do the math at home
You don't need anything fancy for this.
- Find the total mileage for the route (round trip, not one-way, unless the trail description says otherwise).
- Find the total elevation gain. Most trail apps and guidebooks list this. If they only give you a high point and a trailhead elevation, subtract those, though know that undersells it a little on trails with rolling ups and downs.
- Divide gain by mileage.
Here's roughly how I sort the result, based on my own hikes and my own fitness. Your mileage may vary, literally.
- Under 200 feet per mile — easy grade, good for a first-season hike or a day you want to bring a slower group.
- 200 to 350 feet per mile — moderate. You'll be working, but steadily.
- 350 to 500 feet per mile — this is where I start planning an earlier start time and more water. It's a real climb.
- Over 500 feet per mile — steep. Some of the popular Wasatch trails fall here. Doable, but you'll want to be honest with yourself about your conditioning before you commit a whole family to it.
These aren't hard rules. They're just where I've landed after a lot of hikes and a lot of spreadsheet rows.
Do this at home before you go
Pick a trail you're considering this season. Look up its mileage and its total gain, do the division, and write the number down somewhere you'll see it again before the hike. I keep mine in the same spreadsheet where I log water and start times. You can use an index card. Doesn't matter, as long as you actually look at it before you're standing at the trailhead deciding whether you brought enough water.
If the number surprises you, that's the whole point of the exercise. Better to be surprised at your kitchen table than at mile two.
A word on kids and gain per mile
If you're hiking with kids, this number is even more useful, because kids don't pace themselves the way adults do. They sprint the flat sections and then stall out on the steep ones. My 11-year-old asked me once why we always turn around on cloudy days before the summit, and I explained the thunderstorm timing to him, the way I've explained it to you. A few weeks later I heard him repeat the whole thing to a friend's dad on the trail, like he'd invented it. That felt good, honestly. But it also made me realize kids absorb the reasoning if you give it to them straight, and gain per mile is the same kind of thing. If you tell a ten-year-old "we're climbing 500 feet in the next mile," that means something to them in a way "the trail keeps going" doesn't.
One opinion I'll repeat here
Read the elevation profile, not just the mileage. I said it last lesson and I'll keep saying it, because it's the single biggest mistake I see new hikers make, and it was my mistake too. Mileage tells you how long you'll be out. Gain per mile tells you how hard it's going to be. You need both numbers before you decide anything about water, timing, or who's coming with you.
Before next time
Do the gain-per-mile math on two trails you're curious about this season, one you think is easy and one you think might be a stretch. Bring both numbers to class and we'll see if your gut matched the math.