Hiking with a backpack is a heck of a lot more work than hiking without one. It feels harder, but also you're burning more calories — which is important to know as you're planning your snacks and meals for the trip.

iOS: We already know that for various users, iOS 11.1 makes media playback stutter, breaks audio control on the lock screen, and autocorrects the word "I" to an unrecognisable character. But there's more! It also breaks the Calculator app.

If you're a millennial and having trouble saving up for a home, Australian millionaire Tim Gurner has some simple advice for you: Stop eating so much avocado toast. You'll never be able to save for a home that way.

We all know small spending habits add up, but they might add up more than you think. It's easy enough to come up with a monthly calculation of how much we spend on a pack of cigarettes or a cup of coffee every day. But what about the opportunity cost of that spending?

How many kilojoules are in your usual night at the bar? Doing maths with kilojoules is probably not part of your fun night out. Instead, here's a calculator that will give you a good estimate before (or after) the fact.

It's not hard to develop a basic diet and exercise plan the you can stick to over the years, but fine-tuning your progress offers a different set of challenges -- often in the form of maths. BodyBuilding.com put together a series of calculators to do the hard work for you so you can figure out exactly what you need to do to meet your health and fitness goals.

Saving for retirement seems overwhelming, and a big part of that is that it's just so much money. For example, if you're 40, you're supposed to have twice your annual salary saved. If you're starting late, that might seem impossible. Like all goals, it helps to start small, and NerdWallet's new retirement calculator helps you do just that.

Try as we might to fight or deny it, old age will impact our running and athletic ability. By age 35, the rates of decline are so predictably linear that this calculator by a Yale economics professor maps out just how slowly you can expect to run the same distance as the years run by.

Commuting doesn't have to be a waste. There are plenty of ways to get more out of it. If you're curious, though, this calculator tells you just how much time and money you'll spend commuting in your lifetime.

The staggering cost of child care alone is enough to convince some parents to quit their job and stay at home with the kids. At the same time, can your family survive without your income? This calculator will help you figure it out.

OS X: Numi is a calculator that can handle multiple operations at once but still give you the answer you intended. For example, if you've wondered what five days from next Tuesday is, or what a 15% discount on a 50 Euro item would be in Australian dollars, Numi can tell you quickly and without you having to do each operation separately.

Let's say you have a great recipe for a sheet cake, but you only have round cake pans. Or maybe you have a great recipe for pasta salad that only serves 2, rather than the 7 you need it for. You could do a lot of maths yourself, or you could use our nifty calculator to scale your recipe.

Quick: How many grams are in an ounce? How many euros is $1 worth? What's the square root of 65? Windows 10's search in the taskbar can answer these and similar questions.

For most of us, financial independence won't come easy. It takes years of spending less than you earn. If you're curious just how long it will take for you to reach this stage, give this calculator a try.

Chromebook's browser-based operating system may be focused on the web, but its built-in app launcher has a few tricks up its sleeve -- including performing calculations and conversions without ever opening up a web page.

Algebra can be tough to figure out, and textbook answer keys often don't display the step-by-step solutions so crucial to learning. Mathpapa is a website that walks you through each step of an algebraic solution.

Splitting the rent or divvying up mum's estate can be tricky when multiple factors are involved (such as who got the biggest room, or who mum loved best). Spliddit uses maths and economic principles to come up with the fairest solutions.

With consistent savings and (hopefully) a decent interest rate on those savings, you might be able to become a millionaire. When and what will it take? This interactive calculator will show you.

Building your first PC can be an overwhelming experience -- there are just so many different components to choose from. ChooseMyPC gives you a starting point by asking a few questions, along with your budget.