Can someone help me calculate cals burned?

It's all an estimate...and personally, with your stats I don't think you're burning 200+ calories in under 30 minutes of walking on a treadmill. Probably about half of what your treadmill tells you is probably more accurate. I find it very difficult to believe you would burn 8 calories per minute above and beyond your basal calories with your stats.

A good way to estimate this is just chalk it up to about 5 calories per minute...or 70-80 calories per mile walked. It's better to be conservative here.

Use a heart rate monitor and then you wont have to guess.

Gee, thanks for the buzz kill.

In all seriousness, do you not think that pushing a child up an incline (not steep, by any means but still - not flat ground) is only burning about 5 cals/ minute? That is so unmotivating for me, lol.

I don't usually eat back all my exercise calories because I actually did figure that the real number I burned was less than what the treadmill is telling me, but not by half! :sad:

No, it burns more.

I tested mowing the lawn several times, has a max speed not limited by my fitness level, so not going to change except as I lose enough weight.

It was the same as walking 4 mph flat with a 15 lb backpack, for me about HR 125 bpm.
Walking flat with no extra weight is only 90 bpm.
But pushing extra 30 lb mower over bumpy ground is not the same as carrying 15 extra.
So until you test, like if you are going to do this frequently enough to matter, you don't know what it equates to.

And you can confirm what the treadmill is telling you too, since this formula in studies has was shown to be within 4% of measured.
Also, the Gross option is what the treadmill or HRM or database would be telling you. Net option is what you'd log to eat back.
http://www.exrx.net/Calculators/WalkRunMETs.html

And ya, at your weight, sadly it appears only 118 cal burned in 25 min if you went 4 mph flat. Gonna have to get that incline up to actually make it a workout for you that burns more calories.

If you search MFP Exercise database for stroller, it's in there.

Thanks, everyone. I really appreciate the advice. I have been thinking of getting a fitbit or something similar, maybe I will look into that this weekend. I don't have too much more that I would like to lose so I wasn't sure if it would really be worth it for me or not, but I will think about it and talk to the hubs anyway.

My treadmill actually does have a 'pulse indicator', would that be anywhere near accurate? Just a little metal spot where you put a thumb to calculate HR.

So first - Fitbit won't know you are pushing a stroller either, regarding this specific case. It'll be seeing impacts and deciding if walking or running, and how long the stride is compared to expected. The calories based on that.
In fact lots of inclines and carrying backpack and pushing mower/stroller is exactly when you need to over-write Fitbit's estimate with a better one.
But for the day to day stuff and normal walking - excellent. But if not much to lose, may not be worth it if you have a sense of right amount to eat for your activity. Maintenance obviously being higher than now.

The treadmill's own HRM or it reading say a Polar HR strap has no bearing on the reported calorie burn - it merely allows displaying the HR on the screen. They may have some built in program to use the info with desired settings, to say vary it based on HR range you want to use.
Besides, if it's using the standard lab tested formula's - more accurate than HRM anyway.
Does it ask for weight at the least, and you use it?

No, doesn't ask for weight. I got this second hand and I don't have the original instructions but it doesn't seem too technically advanced...

Oh, forget it's estimate of calories burned. Use that website link I gave.

Even MFP's entries are based on that, but you must hit the speed in the description for the whole time.
Many people think it over-estimates because they aren't honest with the entry.
Just because you eventually got up to 4 mph say doesn't mean you did 4 mph for 60 min.

Right, that makes sense.

What is the "grade"?

% incline as called on some treadmills.

NOT degrees though, as some countries or equipment may use. That requires conversion.
45 degree incline, would be 100% grade.