If you were looking for something that would help your trade transactions easier to manage, this is just the app for you.

No, it’s not a regular calculator, and yes, there’s a nice one made by Apple already in the iPhone. I’m also aware that there are too many (mostly worthless) calculators out there in the App Store, but none of them is in the same league as Perishables. Perishables is an intelligent business application, one with some genuine utility.

And it’s not for you if you don’t buy and sell things every day. For those involved in trade, however, it is certain to be indispensably useful. As the developer’s note in the App Store says, this app is for:

anyone buying, pricing, or selling perishables such as fruits, vegetables, flowers, seafood, meat, film, canned goods..

It’s a big list, but you get the idea. Now, this is how it works. When dealing in trade of perishable goods, it is often tricky to work out how to ensure you get the margin you want. The trick is to work out the inevitable spoilage, and factor it into your calculations. This is the most important task the calculator performs for you: you feed in the purchase rate and spoilage percentage, and specify what return margin you want, and you get the effective price, just like that.

There’s lots more to the calculator, though. You can calculate:

• Gross Margin
• Markup based on spoilage rate
• Discounts and Markdowns
• % Total
• % Change

Like I said, for someone involved in trade, its hard to think of a more functional app. In fact, for many, it’s probably a good idea to buy the iPhone AND get locked into an AT&T contract just for this efficient business calculator.

The App Store is full of quirky and fun apps, but it’s good to see that some developers are really thinking things through and coming up with apps that are really useful, and not just meant to appeal to iPhone fans.