Do I have to pay employer National Insurance on everyone I employ?

Yes, as an employer you generally pay secondary Class 1 National Insurance on each employee's earnings above the secondary threshold, on top of their gross salary — this is a real additional cost to budget for, not something deducted from the employee. The employer NI threshold was lowered and the rate increased from April 2025, making it bite earlier than in previous years, so it's worth checking the current threshold and rate on gov.uk or with your accountant before finalising a salary offer. Many small businesses can reduce this cost using the Employment Allowance if they're eligible.