Best way to track a workout

I went to a website that calculates calories burned for each exercise I do - swimming, lifting weights, treadmill, elliptical, etc. I calculated an hour for each one and figured out the average.
I learned that, on average, I burn 330 calories per hour of exercise. That is what I enter into MFP.

My main message would be not to over-stress about it.

Consistency is most important, both in doing your exercise, and in recording it. In that kind of context, a month or so on your new routine will tell you whether your total calorie tracking is right on (sensible weight loss rate), or you should eat more (losing at a rate that creates health risk) or eat less (losing more slowly than you'd like, and faster would still be quite safe). Your results will even give you an indication about how much more/less to eat, if adjustment is needed.

A common strategy around here is to use the MFP exercise database estimates, but start by eating back a portion of them out of worry that they're potentially over-estimated. 50% is common. (Please note that this is completely arbitrary, not magically accurate ). Then, you adjust after a month or so. (If you seem to be losing weight very fast, and begin to feel weak/fatigued for otherwise unexplained reasons, then eat more before the month or so is done.)

That said:

* Heart rate monitor (HRM) based devices tend to be somewhat reasonable estimators for steady state moderate intensity cardio, but not as accurate for very low intensity, very high intensity, intervals (normal or high intensity), anything involving much resistance (like weight training), and things involving overhead movement with intensity. If you happen to have an unusual heart rate response or maximum (not all that uncommon), they'll be somewhat less accurate. (People think HRMs measure calorie burn. They don't. They estimate it.)

* Fitness trackers that ask you to tell it what exercise you're doing, or that use measurements of things other than heart rates (speed, arm movements, altitude changes, etc.) to make reasonable guesses, have the potential to be a bit more accurate for a range of activities . . . but I haven't seen any decent evidence suggesting that they exploit these additional measurments well when they produce their estimates (there may be such evidence pro/con, I'm just professing ignorance ).

* For strength training, the METS-based estimates (like MFP's) are as likely to be accurate as anything, and more accurate than pure HRM estimates. Strength training is important for a variety of reasons, but it doesn't burn bundles of calories.

* There are specialized calculators and formulas for certain sports/activities, like walking and running. Those can take more variables into account, and potentially be more accurate.

* Some exercise machines actually measure the power you apply, in watts. If these also take into account your weight (if a body-weight-moving activity), the machine estimates may be fairly accurate, especially for activities (like cycling) that have a fairly narrow efficiency range. Other machines that don't know your weight/age are pretty iffy, and can over-estimate.

Now, go back and read the first paragraph: Start by keeping it simple. Be consistent. Do exercises you find fun and want to do. Observe your weight loss results. Adjust intake as needed to healthfully pursue your goals. Simple!

Best wishes!

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Depends on what exactly you mean by a "workout" as that means many different things to different people.

Both cardio and strength/resistance training have many different modalities which make calorie estimating techniques easier/harder or more/less accurate.
You mention machines but are they cardio machines or weights machines?

What exactly are you doing OP?