Tier 1 Simplified Retirement Benefit Estimate Post February 28, 2020 You can use the calculator below to estimate your retirement benefit. Age at Retirement Years of Service Biweekly Salary Results: Average Monthly Compensation Service Credit Age at Retirement Retirement Benefit Your years of service credit and/or age does not qualify you for early retirement. Please check the Summary Plan Description for early retirement requirements. Final Compensation is the monthly average of the highest 12 consecutive months of compensation earned.