Yes, as business savings accounts pay interest gross (without tax deducted), you need to pay tax on the interest earned. The amount you need to pay depends on your business type. If you’re a sole trader, you only need to pay tax on the amount you earn that’s above the tax-free personal allowance. You should state how much interest you’ve earned in your self-assessment tax return.  If you’re a limited company, you pay corporation tax, and you need to include any interest earned on business savings in your profit calculations.