Turnover is simply the amount of money that goes through a business.
IE - Business A sells cat beds at £10 per unit, they sell 90,000 per year. Business A buys the cat-beds at £9.50. They pay £5,000 a year for premises. £1,000 a year for professional services. £20,000 a year for staff. £2,000 a year for peripherals.
Business A has a turnover of £900,000 a year.
Business A has £22,000 a year profits, subject to 20% corporation tax. So £17,600 profit on £900,000 turnover.
Business B sells professional services. They charge £1,000 a day. They have three employees that work from home. Their employees earn £80,000 a year. All employees are engaged full-time they have four weeks off a year. NI contribution is £900 pcm. Pension contribution is £200 pcm. Professional services cost £20,000 a year.
Business B turns over £720,000 a year.
Business B has a profit of £447,000 a year. Subject to 20% corporation tax, so £357,680.
They are VERY rough figures.
But a headline high-turnover doesn't necessarily translate into a decent profit. It depends entirely upon the business.