The basic calculation

Estimated annual benefit = potential labour-cost impact + other quantified benefits − annual maintenance.

Payback (months) = installed investment ÷ estimated annual benefit × 12.

Labour-cost impact is not the same as savings

Most projects redeploy operators to other roles rather than reduce headcount. The financial effect depends on what those people do next. Call it impact, and say what assumption you used.

Include the costs that are easy to forget

• Installation, utilities and floor works

• Training and ramp-up losses

• Spare parts and annual maintenance

• Internal engineering time

Include benefits you can quantify

• Additional output where the line was constrained

• Scrap, rework and complaint costs

• Overtime and temporary labour for peaks

Keep it an estimate

A planning estimate supports a decision to investigate further. Actual project economics depend on application, utilisation, engineering scope, labour deployment and operating conditions.