A resistance band is a stretchy loop or strip of rubber that pulls back when you stretch it. It costs about as much as a takeaway lunch, fits in a drawer and works in a hotel room. It also has one quirk that dumbbells don't: the harder you stretch it, the harder it pulls. Once you understand that, choosing the right strength gets much easier.
A 10 kg dumbbell weighs 10 kg at the bottom of a curl and 10 kg at the top. A band doesn't work like that. At rest it is slack, and the pull builds as you lengthen it. The manufacturer guide for one well-known therapy band brand lists a mid-strength band at about 4.6 lb of pull when stretched to double its length and about 6.7 lb at triple length, roughly 1.5 times as much. Between colours, each step up adds around 25% more pull. Other brands differ, but the shape is the same: stretch more, pull more.
That has two practical effects. First, the same band can feel easy or brutal depending on how you set up: standing further from the anchor, or gripping closer to it, changes the load. Second, the easy part of an exercise is the start and the hard part is the finish. For a row or a press that is often fine, because many people are strongest in the middle of the movement anyway.
Loop bands (sometimes called power bands) are one long closed circle. You can loop them round a pole, under your feet, around your thighs or over a pull-up bar. They are the most versatile and usually come in a range of widths for different strengths. Heavy ones are used to help with assisted pull-ups.
Tube bands with handles look like a skipping rope made of rubber, with a handle each end and often a door anchor. They feel the most like a cable machine, which suits rows, presses and curls.
Flat strips and mini loops are thin, light and cheap. They are best for warm-ups, glute work and physio-style exercises, and they are not the best choice if your main aim is to get stronger in big movements like squats and rows.
Yes, for beginners. A 2019 systematic review in SAGE Open Medicine pooled eight trials and concluded that elastic resistance training gave similar strength gains to conventional resistance training, with no significant difference for upper or lower limbs. The catch is effort: bands only work if your last few reps feel genuinely hard. That is the whole choice in a sentence, and the way to check it is simple.
Choose the band that makes a set of 8 to 15 reps end with about two reps left in the tank, and use the same band for the same exercise next week. If you could do 20 or more clean reps, it is too light. If you can't reach 6 with good form, it is too heavy. Because small muscles and big muscles differ so much, most people end up needing more than one band: a lighter one for shoulders, curls and arm work, and a heavier one for rows, squats and hip hinges. If you can only buy one, a set of several strengths or a pair of single bands will serve you much better than one in the middle.
On a small budget (around €10–15): one or two single loop bands in different strengths. Check that the strengths are labelled with a kg range, not just a colour, because colours mean different things on different brands.
In the middle (around €20–35): a graded set of loop bands. For a beginner this is the best value, because you will use the lighter ones for small muscles and the heavier ones for rows and squats.
If you want more: tube bands with handles and a door anchor if you miss the feel of a machine, or a bundle with a bag and guide. A bigger price rarely means a better band, so spend extra only on something you will actually use.