The best kettlebell for a UK home gym depends on whether you want one weight or several. A fixed cast-iron bell is a single weight with no mechanism. The Bowflex SelectTech 840 (3.5 to 18 kg) and PowerBlock Pro (8 to 16 kg) pack several weights into one unit. Ranking here follows published specification and price, not testing.
Is an adjustable kettlebell better than a fixed one?
Neither is better in every case: an adjustable kettlebell gives several weights in one unit, while a fixed kettlebell is a single weight with no mechanism to inspect. A fixed bell is one piece of iron with one weight, so there is nothing to set or lock and only the handle and any coating to look over. The trade-off is that every new weight is another bell to buy and store.
An adjustable kettlebell packs several weights into one body. The Bowflex lists six settings and the PowerBlock 18-35 lb model lists four. The cost is a larger body than a single fixed bell, a mechanism that both makers tell you to inspect, and a ceiling: each unit stops at its top setting.
Compared from the makers' specifications
| Model | Weight settings | Adjustment | Stated dimensions | Warranty |
|---|---|---|---|---|
| Bowflex SelectTech 840 | 3.5, 5.5, 9, 11, 16, 18 kg | Rotating dial | 22.4 x 17.8 x 31.8 cm | 2 years on parts |
| PowerBlock Pro 18-35 lb | 18, 22, 26, 35 lb (8, 10, 12, 16 kg) | Magnetic selector pin | 5.75 x 4.25 x 10 in (about 14.6 x 10.8 x 25.4 cm) | 5 years |
| PowerBlock Pro 35-62 lb | 35, 44, 53, 62 lb (no kg values published) | Magnetic selector pin | 8 x 5.5 x 11.25 in (about 20.3 x 14.0 x 28.6 cm) | 5 years |
| Chase Fitness fixed cast iron 20 kg | One weight: 20 kg | None | Not published | Not published |
Centimetre figures for PowerBlock are converted from the inches the maker publishes, and the Chase Fitness bell has no maker page with a specification. The Bowflex is around £199 (checked Oct 2026) and the Chase Fitness bell around £48.95 (checked Oct 2026). PowerBlock's maker page is a US-dollar store page and no UK price is confirmed here, so check the current price with a UK dealer. Our Bowflex 840 review and PowerBlock review go through each one in more detail.
What weights does the Bowflex SelectTech 840 offer?
Bowflex lists six settings: 3.5, 5.5, 9, 11, 16 and 18 kg (8, 12, 20, 25, 35 and 40 lb). The manual says these are estimated values and can vary because of manufacturing variances. The steps are uneven, with 2 kg between 9 and 11 kg but 5 kg between 11 and 16 kg.
The manual's parts list shows five plates of 4, 8, 5, 10 and 5 lb. Added to the 8 lb handle, those give the six settings, which is why the jumps are uneven. That is arithmetic from the manual's figures, not a maker statement. Anyone who progresses in small increments should look at the gaps before buying.
Which PowerBlock Pro size range should you look at?
For lighter weights the 18-35 lb model (8 to 16 kg) is the one PowerBlock describes as suited to beginners and functional fitness training, while the 35-62 lb model is described as built for advanced strength, power and endurance training. Those are the maker's descriptions, not findings on this page.
The 18-35 lb model starts at 8 kg, so it does not cover very light bells, and the maker states it cannot be expanded beyond 35 lb. Both Pro models list a 32.77 mm handle. PowerBlock also lists a Sport 10-20 lb model with a 34 mm handle, but its range page marks it sold out and it is a different product line.
What to check before buying
- Weight range and steps. Look at the actual settings, not just the range, because uneven steps change how you progress.
- Top weight. Adjustable units cannot be expanded. PowerBlock points buyers who need more than 35 lb to its separate 35-62 lb model.
- Footprint and height. Adjustable bells sit on or with a base or stack, so check the stated dimensions against your shelf or floor space.
- Warranty terms. Both makers exclude commercial use and dropping the bell. Bowflex's manual states its warranty text applies to purchases in the US and Canada and sends other buyers to a local distributor, so ask the UK seller who handles claims.
- Safety instructions. Both manuals require inspection before use and say never to drop the kettlebell.
- Delivery and returns. The Bowflex UK page lists an approximate delivery term of 28 days from order confirmation for credit card payments and a 7-day cooling-off period. GOV.UK business guidance says distance-sale customers can cancel up to 14 days after delivery, so confirm which terms apply to your seller.
Can I use an adjustable kettlebell on any floor?
Both manuals say never to drop the kettlebell and to place it directly on the floor, so the floor needs to take a heavy load. PowerBlock's manual says dropping can damage floor surfaces as well as the product, and both makers say dropping voids the warranty. Bowflex also asks for a free area 0.6 m beyond the maximum reach of the exercise in all directions. See our home gym flooring guide.
Are adjustable kettlebells suitable for children?
No maker positions them for children. Bowflex says its kettlebell is not intended for anyone under 14, and PowerBlock says to keep children under 18 away and that anyone under 18 must always have parental supervision and instruction. Both makers advise consulting a physician before starting an exercise programme, and a qualified coach can advise on technique.
Which suits which situation?
Bowflex SelectTech 840
The Bowflex covers the widest span, 3.5 to 18 kg. On paper that suits a household where several people share one bell, or someone who wants a light setting now and a heavier one later. The maker lists 2 years on parts, shorter than PowerBlock's 5 years, and the top setting is 18 kg.
PowerBlock Pro 18-35 lb
This model starts at 8 kg and tops out at 16 kg, a narrower span with a higher starting point. It is the better fit for someone who does not need very light weights. A buyer expecting to pass 16 kg should look at the 35-62 lb model or plan to add a fixed bell.
Fixed cast-iron kettlebells
The Where to buy block lists a fixed 20 kg cast-iron kettlebell from Chase Fitness. No maker specification is available, so only the category is described. A fixed bell makes sense if you already know which single weight you will use or plan to buy bells one at a time. It makes less sense if you want to cover a wide range from one unit.
Who should skip adjustable kettlebells?
If you only ever want one weight, an adjustable unit adds a mechanism you do not need. The Bowflex's assembly weight is 18.4 kg including its base, so it is not something to carry around casually. If you are undecided between tools, read our kettlebell vs dumbbell comparison, the adjustable kettlebell guide and the adjustable dumbbells guide. The NHS recommends strengthening activities for all the major muscle groups on at least 2 days a week and lists lifting weights among its examples, without favouring one tool.
