Work out your own numbers

Why these exist

Almost every piece of advice in this category is written as a range, because a range is safe to publish. "Five to ten percent of bodyweight" is correct and it is also the point at which most people close the tab, because what they wanted was a number of pounds and a plan for week three.

Each of these commits to a specific answer for the inputs you give it, and then shows the reasoning underneath so you can disagree with it. That matters more than the arithmetic: a calculator that hides its assumptions is just an opinion with a form around it.

Which one you want

If you have already decided on a vest and want to know how heavy to start, use the vest weight calculator. It gives you a starting load as a number of pounds and a twelve-week progression, with a ceiling built in so it cannot walk you into a weight a vest should not carry.

If you already ruck and want to know what the weight is actually doing, use the rucking calorie calculator. It uses a load-carriage equation rather than a flat activity value, so the pack on your back changes the answer — and it will tell you the added load is worth less than you have probably read.

If you have not decided between a vest, a pack and a walking pad at all, start with the finder quiz. It asks about your space, your joints and your goal, and one of its four possible answers is that you should not add load yet — which is the right answer often enough to be worth including.

What these tools will not do

None of them knows anything about you beyond what you type in. The vest calculator cannot see that your left shoulder has been complaining since February, the rucking calculator does not know your metabolism, and the quiz cannot read a bone scan. Every one of them is a starting point that assumes you are broadly healthy and already walking regularly, and each says so where it matters.

They also do not recommend specific products, and that is deliberate rather than an omission. A calculator that ends in a buy button has an obvious reason to hand you a number that requires buying something. These end in a number and a link to the guide that explains it, and the guides describe specification profiles rather than model names — because prices and models on this gear change faster than any page can honestly track.

How accurate is any of this

The vest calculator is arithmetic applied to a widely used guideline, so its precision is the guideline's precision: the four-to-ten percent band is a reasonable starting range for most healthy adults, and individual tolerance varies more than the band suggests. Treat the output as a sensible first load rather than an optimised one.

The rucking calculator uses the Pandolf load-carriage equation, which was developed for military load-carriage research and is the reason the pack on your back changes the result at all. It is well validated for level and uphill walking at steady paces, and it is known to overestimate on descents. Any calorie figure from any source, including your watch, is an estimate — compare a number against your own previous numbers rather than against someone else's device.

The quiz is the bluntest of the three, because the questions that actually decide between a vest, a pack and a pad are few and coarse: where you will walk, what your joints tolerate, and what you are training for. It will occasionally tell you something you did not want to hear, which is the only reason it is worth running.