Commercial Mortgage Payment Calculator: Estimate Your Costs
Published on 23 March 2026
Why Calculate Before Applying?
Calculators provide instant clarity on affordability. They show how interest rates impact monthly commitments. They model different scenarios. You can test various loan amounts and terms before speaking to lenders.
Accurate planning prevents over-extension. Many business failures stem not from poor trading but from excessive debt servicing costs. A calculator identifies sustainable borrowing levels.
Core Calculation Components
- Loan amount (the principal you borrow)
- Interest rate (fixed or variable)
- Loan term (typically 5 to 25 years)
- Arrangement fees and costs
- Annual payment changes for variable mortgages
A £500,000 mortgage at 5.5% over 15 years costs approximately £3,968 monthly. The same mortgage at 4.5% costs £3,556 monthly. One percentage point saves £412 monthly or £73,920 over the term.
Practical Payment Scenarios
| Loan Amount | Rate | Term | Monthly Cost |
|---|---|---|---|
| £250,000 | 5.0% | 10 years | £2,652 |
| £500,000 | 5.5% | 15 years | £3,968 |
| £750,000 | 4.8% | 20 years | £4,549 |
| £1,000,000 | 5.2% | 25 years | £5,859 |
Beyond the Mortgage Payment
Your mortgage payment covers only principal and interest. Budget separately for buildings insurance, property maintenance, business rates, and landlord insurance if applicable. These can add 30% to 50% to total property costs.