There's a web site called www.healthstatus.com if you go to that site go to calories burned and you'll find a calories burned estimator, type in your weight, and scroll down to bicycleing, and type in the minutes you spend on your bike in the box that describes in mph how fast you go, then scroll down to the bottom, hit calculate, and it will tell you approx how many calories you burned. I wounder how acurate that is?? For me, at 248lbs, and going 15 mph for 51 mins, my calorie burn is 1099 calories, that seems high to me, but if it's even close, then this bicycleing this is the best kept secret in the world for weight loss.
Paul

The calc I use in my spreadsheet would give me 306 Cal. - TF

While I like the health status site, it is very optimistic when it comes to calculating calories burned. A lot of those sites are.

Estimate about 500 calories per hour or about 30-35 calories per mile and you'll likely have a more accurate count.

15 mph for 51 minutes would put you at either 425 calories (using 500 calories per hour), or 382.5 to 446.25 (using the 30-35 calories per mile).

I think you guys are probably right, 1099 calories just seemed too high, I just knew it was too good to be true, but 306-425 is still pretty good.
Paul

I always figured around 40 per mile. Not even sure where I got that, so I certainly wouldn't swear by it.

I just tried it. I gave me 672 calories for 1 hour@ 14-16 mph. For 15 mph that's 45 per mile, so too high, but not that far off. OTOH, I also tried the "Target Heart Rate" calculator. It gave me 81-114 bpm for average fitness & 114-138 bpm for "superior" fitness. Sunday I did a 75 mile ride and averaged 163 for the entire ride. Their calculators are worth what you pay to use them.

Those estimating sites are BS. The metrics that Machka posted are BS as well. Way too many variables to boil it down like that.

I would swear at that metric, not by it. You'll burn a lot more calories doing an interval up a steel hill for a mile than you would doing a flat mile at a 14 mph recovery ride pace.

The OP wants an estimate. Some methods are more accurate than others but all are valid as long as you know their limitations.

But when you come down the other side of the hill, you're burning next to no calories. It all averages out.

People seem to forget that unless they are doing a Point A to Point B ride, or unless there's been an earthquake at the start/finish area causing the start/finish area to shoot way up in the air, the climbing and the descending equal out.

An equal amount of ascending and descending does not mean that the effort averages out. Come on, you are experienced enough to know better.

Unless you have some basis to "calibrate" them, their limitations pretty much invalidate them.

Agreed.

But it doesn't; You'll spend a lot more time going up than down. If you go up a 1 mile hill @ 10 mph, it will take 6 minutes. If you then turn around and go down at 30 mph, it will only take 2 minutes.

Glad someone here understands basic concepts.

And riding very long distances while keeping track of calories consumed and weight lost helps validate those estimates.

On a theoretical hill yes. But the real world may get in the way! Sharp curves or traffic control devices may limit safe downhill speeds. (This is even more true on speedskates that effectively have no brakes)

All the more reason that it doesn't "even out."

Only a powermeter can give an accurate estimate of calories burned, and even that will have bias. But you can calculate calories output from watts measured. But a rule of thumb like 30 cal/mile is close enough, especially if it jibes w/ calories in and change in weight.

Everything depends on intensity. But I agree that if you want a rough average, say 30 - 35 kcal per mile. That still makes a fast hour on a bike a pretty good deal for losing weight, as long as you don't reward yourself for your effort with a big mac and fries.

Until I get my Quarq power meter, I've been using 30-40 calories per mile depending on intensity. Been working pretty good so far.

248lbs and calculating calories I assume you have a weight loss goal.

Listen to your body and eat sensibly when it requires food, ride hard, and get proper rest. Don't worry about the numbers.

One (rough) way to look at it is using formulas is probably ~60% accurate, a proper heart-rate monitor is about 80% accurate, and a power meter is about 90% accurate. That's a complete SWAG on my part but the ratio between the three is probably along those lines.

I've seen over time that rides up to medium-high intensity seem to be less kJ worked than the HRM calculates for the same effort, whereas intense rides are always higher. But either ways the difference is 10% or less.

One thing I've learned over time is that if you are really trying to drop weight it's best to do it in a low intensity part of your rising season. For me, anyway, once I'm consistently over 5 hours of riding a week, my appetite makes it neigh impossible to keep a calorie deficit going.

Keep a scale by your bed and by your bike. Weigh yourself before and after sleeping and riding.

Take the average of all four measurements per day and then you know - on average how much you actually weigh. What you hope is to occasionally see lower numbers show up after riding and after sleeping. And hopefully not set any new "peaks."

Pounds not calories are what matters.

Since I got my power meter, it is interesting to see how much energy (Kjoules) I produce on a ride. I always knew that most of the HR / speed devices were inaccurate and overstated the calories but what was slightly surprising was the amount. Generally, on a hard 3 hour ride I will burn approximately 500 calories an hour. However, that includes at least 4x10 or 2x20 z4 efforts and at least an equal amount time in z3 with an occasional z5/z6. There is zero energy used on descents no matter how fast one goes unless one has to pedal. On rolling terrain, power is easy to make while climbing but once you crest a roller, unless you shift into a bigger gear and really focus on keeping the power up, it drops quickly even though you are pedaling and going fast. To keep the power and energy up, one must go really fast down hill and pedal hard.

IMO, this is one area where the HR based speed calculations go wrong. After you crest a hill, your HR will stay elevated but your energy output is way down and you are now going fast. Eventually HR will catch up but it is just not that accurate. And of course there are aero differences between riders and riding position and wind.