I'm so upset! My husband just bought one of those fat measure calcipilar that measured my body fat at 29! But when I did the calculations on the Zone, my body fat was 18!

I wonder which one I should believe. My husband thinks I am not eating enough for the amount of exercise I'm doind. He thinks my body is burning muscle rather than fat.

Please advise.

What is your perception of the situation?

When you look at your body, do you see a fair amount of bodyfat, or do you have a fairly lean look? I guess I would go with the one that seems more realistic to your perception (or the perception of others, as sometimes we view ourselves differently than others do).

The Fat measure calipers can be more accurate; BUT, only if used correctly.
I think that before using, you should consult an expert and have him/her show you how to use them properly.
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There are the hand-held electronic resistance measurement devices available.
Our YMCA has one, and it measures me at about 17%.
The Dr. Sears tool also has me at about 18%.
So, there is confirmation.
(I think you can buy one on Amazon for about $30.00)
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We have a weight scale at home with a body fat measurement.
An older one, have had for 5+ years or more.
It has me at consistently at 22%, so I know its factory set calibration is off by 5%.
(The body fat portion is not able to be calibrated.).
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Consider going to your local YMCA, check to see if they have one of the Hand-Held electronic Body fat,
and then compare it with your Caliper measurements.
I will bet it is very close to the Dr. Sears tool results.
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Then learn how to use the calipers, properly.
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Honestly, pretty much all body-fat calculators, including calipers, have a wide range of error. Calipers require more skill to use correctly. Whether you use one of the many "tape measure" and bodyweight calculators out there, or scale that calculates bodyfat, there will be a wide range of error from your actual body fat. Personally, I use a BI scale, the Zone calculator, and a USMC calculator and average the 3 of them. Although knowing your BFP matters to some degree, it doesn't need to be exact. It just needs to be consistent in terms of the methods of calculation you use. You are measuring "relative" changes in BFP. As long as your "relative" value is going in the right direction, your are fine even if your "actual" BFP is really a few percent higher or lower.

With all that said, a difference of 11% in readings tells me that one of those readings is seriously in error. Given that a skin-fold caliper requires some training to learn to use correctly, I am going to guess that one is the one that is way off. Most calculators will be within about 3% of one another. I would just go with the Zone calculation and ditch the skinfold caliper until and unless you are trained how to use it (and it does require training).

BTW, the BI and USMC BFP measurements I get are routinely lower than the Zone measurements, but they are within a reasonable range and are consistently lower (although with the BI scale, I have to make sure to use it at about the same time and under as close to identical conditions as possible to get consistent readings).

BTW, I take it a step further. I take measurements every day, but only do calculations every week. I throw out the high and low measurements and get an average for the other 5 days and use that average measurement. As long as the weekly trend is in the right direction, all is well regardless of daily fluctuations.

I would agree, sometimes it isn't about what is accurate, but rather the ongoing trend.

Debates about bodyfat calculators have been had in the past in these forums, and my overall opinion is to use bodyfat calculations as a trend-tracking tool.

There have been comments in the past that the online calculators have been off in some cases, resulting in an over/under-calculation of food blocks for the Zone. Again, I do believe it is possible for these calculators to be off, so one needs to do what feels best for them, what seems reasonable, etc.