gregf83 

kreuzotter.de has a decent calculator that shows a 150lb person cycling at 14mph will burn closer to 23 Cals/mile.

BlazingPedals

For rough calculation, I usually use 35 Cal per mile.

rm -rf

At an easy pace: 25-30 calories per mile. Even with hills!

Even that is a bit high for many riders at a casual pace. Bike are "too" efficient!
A rider at a 16 mph pace might need 120 watts for that speed. That's 120*3.6 = 430 kilojoules per hour. Then divide by 16 miles. About 27 calories per mile.
At 12-13 mph, about 75 watts. That's maybe 23 cal per mile.

Calculating calories with power meters
There have been lots of threads where riders with power meters report calories. The meters calculate kilojoules for the ride, which have a roughly one-to-one correspondence to calories. Somewhere in the range of 22-30 calories for a moderate pace is typical.

The calorie formula is explained here.

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I'm about 170 pounds. From some recent power meter rides:

35 miles, 2200 feet of climbing. Hilly, but mostly at a moderate pace.
1130 kj, that's maybe 1200 calories, plus or minus 10% or so.
34 cal per mile.

19 mile, 700 feet, at a brisk pace 9 miles outbound, easy pace on the same roads back.
537 kj, maybe 600 cal.
31 cal per mile.

42 miles, 2000 feet, moderate pace mostly.
1250 kj, maybe 1350 cal.
32 cal per mile.

A very hilly ride: 55 miles, 5200 feet, all climbing and descending, mostly long, moderate grades at 5-8%
1950 kj, maybe 2100 cal.
just 38 cal per mile!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 flavor lifesavers. 15 cal each.

ride 1/2 mile per lifesaver:

fietsbob

Did you turn into that stiff wind off the North Sea.. ?

Riveting

3,000 calories per 100 miles, is my rule of thumb (with < 3,000' of climbing, and an avg. speed of about 17 mph). Based on actual power meter data (PowerTap G3 Hub)

Bluechip

This last Sunday I had a low effort ride with my wife. We averaged 13mph for 40 miles that took just over 3 hours to complete. I averaged 70 watts for the entire ride. Calorie wise I burned just under 800 calories per Strava with a power meter. So for me (225lbs) I burned 20 calories per mile. I've always preferred to look at colories burned by the hour. So this was about 260 calories per hour.

I did the same ride the day before by myself and averaged close to 18mph and burned over 1400 calories in a little over 2 hours. That works out to 35 calories per mile. This works out to be close to 700 calories per hour.

DrIsotope

I bet if you go look at the breakdown of the ride with your wife, you were coasting (not pedaling) for at least a third, if not half the ride. I did a ride with my wife and one of her coworkers-- who hadn't been on a bike since May. Almost no climbing, and I only pedaled 66% of the ride. Still averaged 96W (129 weighted) and 28kcal/mi. Mathemagic away the huge amount of coasting, and I'm right back at 35kcal/mi.

This morning was 50 miles @ 20.5mph, and I averaged 37kcal/mi-- because there was very little coasting.

caloso

I've done recovery rides that work out to 20 kcal/mile and TT rides that work out to 43 kcal/mile. That's a pretty big discrepancy.

OBoile

See. Speed matters.

DrIsotope

Not coasting is what matters. The fast ride had a whole lot more pedal strokes. Power doesn't count zeroes, so it's really easy for the average to come way down-- I routinely "average" around 160W on mountain rides with +5,000ft of climbing-- on the way up I'm doing over 250 watts, and on the way down I'm just enjoying the effects of gravity. So AFAIC, that 160W average is meaningless. I should save the activity at the top and start a new one for the descent.

Colnago Mixte

Yeah, why not play it safe and stay a fat tub of lard? That's how the pros slim down when starting the season, or used to. Works, it's absolutely foolproof, and not dangerous.

I am a doctor and I'm not ordering anyone to do this, but if you suffer ill effects from it, you're likely in such bad health that you shouldn't be riding a bike at all, you should be in a hospital.


YMMV.

OBoile

Coasting = going slower.
Whether you're coasting occasionally, or simply putting less power into the pedals with each stroke, the result is the same: slower speed and fewer calories expended.

livedarklions

If you really are a doctor, you should realize that any forum like this will likely have some people with eating disorders reading it, and anorectics will be looking for "information" that reinforces their dangerous behavior. You've now made that possibility worse by claiming medical authority for this.

You have no idea how much I exercise and whether or not taking in sufficient calories is a risk for me. I happen to do 2 centuries a week every weekend that the weather allows. I take 150 mile rides on a fairly regular basis. I do not have a lot of body fat. If I don't eat while and after doing that much biking, I feel quite crappy, and it's absolutely unnecessary to fast to lose weight. I do not think the fact that I would get shaky burning many thousands of calories without some calorie intake indicates that I have any sort of "problem".

This is a discussion of nutrition in the "general cycling" forum--why are you talking about professional training as if it were some kind of norm? Pros do all sorts of extreme things at risk to their general health--that's part of the job description. Hell, if that was your standard 10 years ago, you could advise people to figure out how to sneak doses of EPO.

OBoile

It's funny. A lot of people assume pro athletes are perfect examples of healthy living when in fact they often do very unhealthy things in order to maximize their performance. Playing sports is generally good for your health. Playing sports at an elite level often isn't, or at the very least, is no better than doing it on a recreational basis.

rgconner

Remember Jim Fixx?

livedarklions

Yes, I'm really not going to assume that someone who attempts to turn on a dusty cobble road at 35 mph is making long-term preservation of their health a huge priority.

caloso

Jim Fixx died while running, but it's quite a stretch to say that he died because of running. He had a family history of heart disease, was a smoker, suffered stress in his job and home life, and was overweight before taking up running.

124Spider

When I ride my single bike by myself, riding fairly hard (averaging 185 watts or more), I burn a steady 40 calories per mile.

When I ride my single bike with my wife, staying with her, we ride much more slowly. I average only about 90 watts, and burn a steady 25 calories per mile. And we average in the neighborhood of 14 mph on flat ground.

It would surprise me if riding a heavy bike on flat ground, at 12mph, burned more than 25 calories per mile.

fietsbob

You stop for a leisurely Lunch & a Pint?

bruce19

Depends on your weight, speed and the terrain. For my weight (187 lbs), speed (14-19 mph) and terrain (usually 45-65 ft of climbing per mile) I use 10-15 cals. per mile. Totally ballpark. If you want serious accuracy it's going to cost you serious amounts of time and money.

SylvainG

Surprised no one mentioned rolling resistance yet. This will have a good impact on your ride.

topshopper19

I've read in a few articles that your bodyweight is also a contributing factor in calculating calories burned during cycling

Machka 

Not much.

livedarklions

The METS method of estimating calories assumes a linear positive relationship between the weight of the rider and calories burned per hour, and results in vastly higher estimates for people who weigh 250 pounds vs., say, 200 riding at the same speed. I think that's probably valid in an activity like running, but not so much in biking where moving your actual weight really is mitigated somewhat as a factor by the nature of the activity. In general, my completely uninformed lay opinion has no problem with the concept that a bigger body is going to burn more calories to sustain itself even if inactive compared to a smaller inactive body,, but I find the idea that the relationship between weight and calorie needs is the same for all activities really dubious.

DrIsotope

Then let's not forget that the more you do an activity-- say cycling-- the more efficient your body gets at it. So you have to ride further/faster/more often to have the same effect.

Just always guess low for calories. Even if you have a power meter (which I do.) It's pretty easy to ride 200 miles a week and gain weight. I'm living proof.