Business Loan Calculator — Methodology

Step-by-step calculation

Calculate monthly business loan payment, total interest paid, and full amortisation schedule for any loan amount.

1. 1

   Enter loan amount

   Total principal you intend to borrow.

2. 2

   Set the annual interest rate (APR)

   Pre-filled with the typical SME rate for your region — override with the actual rate you're being offered.

3. 3

   Set the loan term

   Toggle between months or years, then enter the term length.

4. 4

   Read monthly payment and total cost

   The calculator shows the fixed monthly payment, total interest paid, and total cost over the full term.

5. 5

   Expand the amortisation schedule

   Click to view the month-by-month breakdown of principal vs interest in each payment.

Assumptions and overrides

Pre-fill rates are mid-range SME rates for each region: US SBA 7(a) ~7.5%, UK SME ~8.5%, SA prime + margin ~14.5%. Actual rates vary by lender, term, credit, and collateral. APR includes fees; lenders quoting headline rates may be missing fee components.

Every region default on the calculator is editable. If your effective rate, fee, or threshold differs from the headline figure shown, type your own number into the field — the calculator recomputes instantly without leaving this page.

Primary sources

Region-tagged primary sources for the default rates, thresholds, and benchmarks used in this calculator.

• USAUS SBA — 7(a) Loan rate ranges
• UKBank of England — Bank Rate (UK base rate)
• SASouth African Reserve Bank — repo + prime

Review cadence and corrections

This methodology and the underlying rate defaults are reviewed at least annually, and immediately following any change to the headline rate from IRS, HMRC, or SARS. Every substantive update is recorded on the public changelog. Spotted an error? See the corrections policy for how to report it.

See the full editorial policy for the standards every page on BusCalcTools is held to.