Ever-changing shipping costs can be hard to track, especially when you're not sure of your package’s weight. A postal scale takes the guesswork out of the process. And because many parcel carriers allow you to buy postage online, you can avoid standing in line at the post office getting your package weighed.

Owning a postal scale is essential for anyone who runs an eBay store, Etsy shop, or other small business that involves shipping items to customers. A home postal scale is also helpful for anyone who mails a large amount of letters or packages.

Postal scales must be more sensitive than bathroom scales designed to weigh people. They must also have a higher maximum weight capacity than kitchen scales, in order to handle large or heavy parcels. There are plenty of factors to consider in choosing the right postal scale, such as a scale’s weight limit, power source, and the clarity of a device’s readout. This guide will give you all this information and more so you can easily select the best postal scale to suit your particular needs.

All postal scales have a maximum weight limit. If you try to weigh items that exceed that weight limit, you could break your scale. Nearly as bad: in the event of an overage, you will usually get an error message on screen rather than a weight reading, rendering the scale useless. Luckily, postal scales are available with weight limits ranging from under 25 pounds to over 500 pounds. Be sure to choose a postal scale with a weight limit appropriate to your needs.

Check the size of the weighing area on any postal scale you're considering. Postal scales will still weigh items accurately with some overhang, but it can be difficult to balance packages on the scales if they're much larger than the weighing area. Plus, extra-large packages on a small set of scales could obscure your view of the display screen.

A quality postal scale should be easy to read. When considering the readability of a postal scale, examine the LCD display screen. It should be large enough to easily make out the numbers when you're standing above it. Ideally, it should be backlit or have a backlighting option so you can easily read the scale in dark or dim rooms.

The majority of postal scales are either battery powered or powered via an AC adapter in a power outlet. You can operate battery-powered postal scales anywhere, but you will need to replace the batteries every so often, and there's a chance they could run out of juice at an inopportune time. If your postal scales are powered by an AC adaptor, you won't have the extra cost of batteries, but your weighing station will need access to an electrical outlet. Some postal scales include the option of using either batteries or an AC adaptor.

Unit of weight: It's fairly common for postal scales to let you switch between imperial and metric weight measurements. This gives you the option to weigh packages in either pounds and ounces or grams and kilograms.

Lift-up stand: Some postal scales feature a lift-up stand. This stand lays flat on the weighing area until you need it, at which point it flips up until it is perpendicular to the weighing area. The purpose of the lift-up stand is to keep poster tubes or other awkwardly shaped packages that might roll or slip off the scale in place while you weigh them.

Auto shutoff: Most battery-powered postal scales have an auto shutoff feature, switching themselves off after a minute or two of disuse in order to conserve battery life. This feature may not be present in models that are plugged into a power outlet.

Wired display unit: You can find postal scales where the LCD display unit is on a long wire, rather than being integrated into the body of the scale. This is useful when you intend to use the scale on the floor, as you won't need to bend down to read the measurement.

Hold or tare functions: Many scales include hold or tare buttons. The hold function locks the displayed weight on the screen so you can remove the package without losing track of its weight. The tare function allows you to zero out the weight of whatever’s on the scale and weigh something else on top of it. You can put a shipping box on the scale, hit the tare button, and then add the item to determine the item’s weight sans packaging.

Postal scales vary widely in price, depending on their size and capacity. Basic postal scales can cost as little as $10 to $30. These are fine for the majority of home users, but if you want a large weight capacity or extra features, you'll need to pay more. Mid-range postal scales cost roughly $30 to $80. In this price range, you will find medium-duty models that will stand up to even the heaviest of home users. High-end postal scales cost $80 to $150. Expect to find models at this price that can weigh items of 200 to 500 pounds. Scales in this price range are usually those tailored to warehouse or industrial uses.

• Choose an accurate postal scale. The vast majority of postal scales arrive pre-calibrated, so in theory, they should be accurate. But this isn't always the case. Try weighing an item that you know the precise weight of to double check. Inaccurate postal scales can cause problems with your mail carrier.
• Find out the overall size of your chosen postal scale. They should be large enough to suit your purposes, but not so large that they take up too much space. Compact models are particularly useful if you need to move them to different locations.
• Check what type of batteries your postal scale takes. The majority of postal scales we've come across take either AA or AAA batteries, but some use smaller flat batteries and others use large 9V batteries.
• Think about how regularly you intend to use your postal scale. Will you be using your scale daily or just every now and again? Postal scales meant for regular use should be sturdy enough to stand up to it.

Q. Are all postal scales digital?
A. In years gone by, postal scales would have either had an analogue dial or even used weights to balance against the item you were weighing. However, the vast majority of modern scales are digital. While you may be able to find an analogue postal scale on the market, they're not very user friendly. Analogue scales are more difficult to read and they lack useful functions such as hold or tare.

Q. How do I clean my postal scale?
A. You may occasionally want to clean your postal scale due to spillage or the general buildup of dirt. To clean it, simply wipe it down with a damp cloth. Avoid getting your postal scale wet, as the moisture could damage the electrical components.

Q. What's the lowest weight a postal scale can measure?
A. If you're likely to be weighing small, light packages, it's important to find out the minimum weight of your chosen postal scale. Some models can weigh items from as little as a tenth of an ounce. Any packages below the minimum weight will register as zero on the display.