Thought this might be useful to people.

I've just been wondering how my metric fibreglass cloth compared to imperial measures. Google helps out here if you just type: "175 grams per square meter in ounces per square yard" in the search box (without the speech marks).

You can also use it for calculations such as working out a rough measure of the weight of the fibreglass inside and out on the black pearl kayak I'm building. Assuming 3 square meters surface area (just guessing this number), 175 grams per square meter fibreglass and an equal weight of epoxy, and applying the fibreglass/epoxy inside and out then I can do something like this:

"(2 * 175 grams) per square meter * (2* 3 meters squared)" = 2.1 kg

Just thought I'd check on http://www.wolframalpha.com and, yes, the exact same syntax works.

In fact wolframalpha lets me go a step further and I can combine unit conversions with calculations eg to add in the weight of the paulownia wood strips assuming the web link I found quoted an accurate density of 20lbs per cubic foot. It's nice the way it shows you in detail how it interprets what you've written:

(2 * 175 grams) per square meter * (2*3 meters squared) + ((20 pounds per cubic foot in kilograms per cubic meter) * 3 square meters * 5 millimeters)

= 6906 grams (and plainly my epoxy/fibreglass ratio must be appalling :)