Kettlebells
Shop the 18 kg KettlebellWhat Size Kettlebell Should I Buy? The UK Guide to Starting Weights (and Why Adjustable Wins)
Swings need a heavier bell than presses, and beginners outgrow their first kettlebell fast. Here are starting weights by exercise and experience, the research on swings, and the BrainGain 9 kg vs 18 kg adjustable kettlebell compared.
"What size kettlebell should I buy?" is one of the most common questions in home fitness, and the honest answer is that one size is never enough. Swings need a heavier bell than presses. Beginners outgrow their first kettlebell in weeks. This guide gives you the starting weights by exercise and experience, explains why an adjustable kettlebell solves the problem, and compares the BrainGain 9 kg and 18 kg adjustable kettlebells.
Want a full home setup? The Core Bench + 18 kg Kettlebell set is £189.99, and our bench exercises guide shows what to do with the bench.
The short version
- Most adults should buy the 18 kg adjustable kettlebell (£89.99, was £124.99). It goes from 4 to 18 kg, covering a beginner's press and an intermediate lifter's swing.
- The 9 kg adjustable kettlebell (£49.99, was £69.99) goes from 2 to 9 kg. It suits beginners who mainly want presses, rows and rehab work, teenagers and lighter users.
- Swings need more weight than presses. Most people swing about twice what they press.
- Research: six weeks of kettlebell swings improved maximal and explosive strength in a 2012 study.
What size kettlebell should I start with?
| Exercise | New to kettlebells | Some training | Experienced |
|---|---|---|---|
| Two-hand swing | 8 to 12 kg | 12 to 16 kg | 16 kg and up |
| Goblet squat | 6 to 10 kg | 10 to 16 kg | 16 kg and up |
| Deadlift | 10 to 14 kg | 14 to 18 kg | 18 kg and up |
| One-arm row | 6 to 10 kg | 10 to 16 kg | 16 kg and up |
| Overhead press | 4 to 6 kg | 6 to 10 kg | 10 to 16 kg |
| Turkish get-up | 2 to 4 kg | 6 to 8 kg | 10 kg and up |
| General starting points, not medical advice. Start at the low end, learn the movement, then move up. Everyone is different. | |||
Look at the spread. A beginner wants 4 to 6 kg for a press and 8 to 12 kg for a swing on the same day. With fixed kettlebells that means buying three or four bells. That is the case for an adjustable one.
Why an adjustable kettlebell makes sense at home
- One bell, seven weights. The BrainGain 18 kg kettlebell replaces seven fixed kettlebells from 4 to 18 kg.
- Space. One kettlebell on the floor instead of a row of them.
- Cost. Seven fixed kettlebells cost far more than £89.99.
- Room to progress. You move up a step when the current weight gets easy, without buying another bell.
BrainGain's own video below shows the seven weights and how the handle turns to change them.
BrainGain shows the 18 kg adjustable kettlebell: seven kettlebells in one, from 4 kg to 18 kg.
BrainGain 9 kg vs 18 kg adjustable kettlebell
| 18 kg Adjustable Kettlebell | 9 kg Adjustable Kettlebell | |
|---|---|---|
| Price | £89.99 (was £124.99) | £49.99 (was £69.99) |
| Range | 4 to 18 kg | 2 to 9 kg |
| Weights | 7 in 1 | 7 in 1 |
| How you change it | turn the handle | turn the handle |
| Good for swings | yes, beginner to intermediate | light swings only |
| Best for | most adults | beginners, rehab, presses, teenagers |
| Warranty | 24 months | 24 months |
| Prices and specifications checked on braingain.fit on 9 November 2026. | ||
For most adults the 18 kg is the right buy. It covers every starting weight in the table above except the heaviest swings and deadlifts. The 9 kg makes sense as a second bell for a partner, or for someone who wants light presses and mobility work. Tech Alchemy's review below covers the 18 kg.
Tech Alchemy reviews the BrainGain 18 kg adjustable kettlebell.
Buy one kettlebell that covers your press and your swing. That means buying one that adjusts.
What the research says about kettlebell swings
A 2012 study by Lake and Lauder in the Journal of Strength and Conditioning Research put adults through six weeks of kettlebell swing training, twice a week. Their half-squat maximum rose by 9.8% and their vertical jump by 19.8%, gains that matched a group doing jump squats. Swings are one of the most time-efficient exercises you can do at home. Our strength and conditioning guide for combat athletes uses them for exactly that reason.
A 15-minute kettlebell workout
- Warm-up, 3 minutes: hip hinges, bodyweight squats, arm circles.
- EMOM, 12 minutes: minute 1, 15 two-hand swings. Minute 2, 8 goblet squats. Minute 3, 8 one-arm rows each side. Repeat four times.
- Weights: heavier for swings and squats, lighter for rows. Turn the handle between exercises.
The best ways to buy
1. 18 kg Adjustable Kettlebell
£89.99 · was £124.99 · 4 to 18 kg · 24-month warranty
The 18 kg adjustable kettlebell is the one to buy for most adults.
2. Core Bench + 18 kg Kettlebell
£189.99 · was £249.99
The Core Bench + 18 kg Kettlebell set adds a folding bench for presses, rows, split squats and hip thrusts.
3. 9 kg Adjustable Kettlebell
£49.99 · was £69.99 · 2 to 9 kg
The 9 kg adjustable kettlebell for beginners, lighter users or a second bell in the house.
4. Intermediate Gym Bundle
£399.00 · was £689.99
The Intermediate Gym Bundle includes the 18 kg kettlebell, the 24 kg SmartBells Evo dumbbells, the stand and the Core Bench.
The verdict
Your swing weight and your press weight are different, so one fixed kettlebell is never the right size for long. For most adults, the BrainGain 18 kg adjustable kettlebell at £89.99 covers 4 to 18 kg in one bell, with a 24-month warranty. Choose the 9 kg at £49.99 for lighter work, or pair the 18 kg with the Core Bench for £189.99.
Frequently Asked Questions
What size kettlebell should a beginner buy?
It depends on the exercise. Beginners often press 4 to 6 kg and swing 8 to 12 kg. An adjustable kettlebell such as the BrainGain 18 kg, which runs from 4 to 18 kg, covers both.
Is an adjustable kettlebell worth it?
For a home gym, yes. One BrainGain adjustable kettlebell replaces seven fixed ones, takes up one spot on the floor and lets you move up in weight without buying another bell.
What is the difference between the BrainGain 9 kg and 18 kg kettlebells?
The 18 kg adjusts from 4 to 18 kg and costs £89.99. The 9 kg adjusts from 2 to 9 kg and costs £49.99. Both have 7 weights, change by turning the handle and come with a 24-month warranty.
Do kettlebell swings build strength?
A 2012 study by Lake and Lauder found six weeks of twice-weekly kettlebell swing training increased half-squat strength by 9.8% and vertical jump by 19.8%.
Should I swing heavier than I press?
Yes. The swing is driven by the hips, so most people swing roughly twice what they can press overhead.
24-month warranty on BrainGain dumbbells, kettlebells and benches in the UK store. Prices checked 9 November 2026.
Keep reading
- BrainGain UK store product pages, prices and specifications checked on braingain.fit on 9 November 2026.
- Lake JP, Lauder MA, "Kettlebell swing training improves maximal and explosive strength", Journal of Strength and Conditioning Research, 2012.
- BrainGain, "BRAINGAIN 18kg Adjustable Kettlebells - 7 Kettlebells in 1", YouTube, 2 February 2023.
- Tech Alchemy, "Review BRAINGAIN 18kg Adjustable Kettlebell 7-in-1", YouTube, 26 June 2025.
- Trustpilot rating for BrainGain: 4.7 stars from 2,000+ reviews, checked 9 November 2026.
This article is for general information and is not medical advice. Prices checked on braingain.fit on 9 November 2026.