Guide · 8 min read
How to find a personal trainer who actually fits you
By Harriet, Founder of knwn ·
There are tens of thousands of personal trainers in the UK. Finding a good one is easy. Finding the right one, for your body, your goals, your schedule and your style, is a different problem entirely. Here's how to do it properly.
1. Get clear on what you actually need
Before you look at a single profile, write down three things: what you want to change, where you'll train (gym, home, online), and how often you can realistically commit. A trainer who's brilliant for a marathon prep is the wrong choice for postnatal recovery. Fit comes before fame.
2. Check qualifications - properly
In the UK, a credible personal trainer holds at least a Level 3 Personal Training qualification from a CIMSPA-recognised provider, plus current insurance and a valid first-aid certificate. For anything more specific including, pre/postnatal, rehabilitation, strength coaching, nutrition, look for a Level 4 specialism or a recognised body such as the Register of Exercise Professionals (REPs) or CIMSPA itself.
Ask to see certificates. A good coach will send them without being asked twice.
3. Match the specialism to your goal
"Personal trainer" is a job title, not a specialism. Within it sit very different practitioners: strength coaches, hypertrophy-focused trainers, rehab specialists, endurance coaches, fat-loss coaches, pre and postnatal specialists, trainers for older adults, trainers for chronic conditions.
The right person should have evidence: qualifications, case studies, client outcomes, of working with people like you, not just people in general.
4. Looking for a fitness coach for women?
If you want a fitness coach for women specifically, for example because you're training around a cycle, through perimenopause, postnatally, or simply prefer a female coach, say so up front. The right coach will have lived experience or formal training in female physiology, not just a generic programme rebranded.
Good signals: continuing education in women's health, clear language around hormones and recovery, and clients with similar profiles to yours.
5. Judge style as carefully as credentials
You'll spend hours with this person, often when you're tired or uncomfortable. Style matters. Some coaches are drill-sergeants. Some are quiet technicians. Some are warm and conversational. None of those is wrong — but the wrong one for you will end the relationship inside a month.
Ask for a discovery call before you commit. Five minutes of conversation tells you more than five pages of bio.
6. Red flags to walk away from
- No verifiable qualifications or insurance.
- Guaranteed results in a fixed number of weeks.
- Pressure to pay for long packages before a trial.
- Selling supplements as part of the coaching offer.
- No structured assessment in the first session.
The knwn. approach
Browsing vs matching
The traditional way to find a personal trainer is to browse - scroll a directory, an Instagram grid or a gym noticeboard, judge a few faces, message a handful of people, hope. It rewards visibility, not fit. The loudest coach wins, not necessarily the right one.
knwn is built the other way around. Every coach in the network is human-vetted before they join: qualifications verified, interviews completed, specialisms confirmed. You answer a short set of questions about your goals, body, schedule and style. We score your answers against every verified coach and introduce you to the right person, with a written reason for the match.
No browsing. No guessing. If it isn't right, we rematch you — no friction, no questions asked.
Common questions
How much does a personal trainer cost in the UK?
Most UK personal trainers charge £40–£100 per hour in person, and £80–£200 per month for fully online coaching. Specialists and senior coaches charge more. Cheapest is rarely best value - fit is.
How long should I commit for?
Start with a single session or a 6-week block. Anything longer before you've trained together is a leap of faith, not a decision.
In person or online?
In person is best if technique is your priority. Online is often better for accountability, programming and flexible schedules and it widens the pool of specialists you can work with.