Short answer: ₹50,000 last drawn basic + DA with 9 years 7 months of service gives ₹2,88,462 — the 7 months round up to a tenth year, and 50,000 × 15/26 × 10 is the whole calculation.
Why basic + DA and not the full salary
The Act names wages, which for most employers means basic plus dearness allowance — not HRA, not the special allowance, not the bonus. Using the CTC or the gross salary inflates the number, and payroll will pay the smaller one.
Five years, and the exceptions
Continuous service of five years is the normal condition. Death and disablement remove it, and some fixed-term contracts are treated differently. If you are close to the line, the exact wording of your appointment letter matters more than any calculator.