Headcount Scenario Planner Calculator

Planner inputs

Build your headcount scenarios

Use realistic assumptions to compare best, base, and worst cases.

Current headcount

Starting employees at the beginning of the plan.

Planned hires (total)

New hires distributed across the selected months.

Annual attrition rate (%)

Expected annual exits expressed as a percentage.

Average annual salary

Used to estimate monthly workforce cost.

Benefit & tax load (%)

Additional cost applied on top of salary.

Planning horizon (months)

Choose up to 36 months for longer cycles.

Start month

First month of the projection window.

Hire distribution

Controls when hires land within the plan.

Scenario swing (%)

Best and worst vary by this amount.

Ramp months (new hires)

Months for a hire to reach full productivity.

Ramp start productivity (%)

Productivity level during the first month.

Attrition handling

Choose whether you backfill exits automatically.

Example

Example scenario data table

Use this sample to understand typical inputs and outputs.

Scenario	Start HC	Planned Hires	Attrition %	Months	Ending HC	Total Cost
Best Case	50	14	10.0	12	63	7,520,000
Base Case	50	12	12.0	12	60	7,100,000
Worst Case	50	10	14.0	12	56	6,820,000

Example totals assume an average salary of 120,000 and 18% load.

Method

Formula used

Headcount projection

Each month updates headcount using hires and expected attrition.

Attrition_m = round(Start_m × (AnnualAttrition ÷ 12))
End_m = max(0, Start_m + Hires_m − Attrition_m)

If “Replace attrition” is selected, hires also backfill exits each month.

Cost and productivity

Monthly cost uses average headcount and loaded compensation.

AvgHC_m = (Start_m + End_m) ÷ 2
Cost_m = AvgHC_m × (Salary ÷ 12) × (1 + Load)

Productive FTE applies a ramp to new hires over selected months.

These formulas are planning approximations. For precision budgeting, layer in role mix, start dates, contractors, and location pay bands.

Guide

How to use this calculator

Enter current headcount and planned hires for the period.
Set annual attrition and loaded compensation assumptions.
Choose a start month and the number of months to project.
Select a hire distribution that matches your recruiting plan.
Adjust scenario swing to stress-test uncertainty.
Press Submit to view results above this form.
Download CSV or PDF to share the plan.

Workforce demand and capacity signals

Headcount planning works best when you translate demand into capacity. Use the planner to test how many roles you need to deliver quarterly goals, service levels, or product milestones. Compare projected productive FTE against your required capacity and note gaps early. If productive FTE lags while costs rise, revisit role mix, start dates, and ramp assumptions. Track headcount alongside productive FTE to explain why staffing can feel tight despite hiring.

Hiring timing and recruiting throughput

The hire distribution control helps you model recruiting realities. A front‑loaded plan assumes fast approvals, strong pipeline flow, and quick start dates. A back‑loaded plan reflects longer time‑to‑fill or phased budget release. Watch monthly hires and attrition together; hiring late in the period can leave you short during peak workload even if ending headcount looks healthy. Use the monthly table to spot bottlenecks in onboarding and team allocation.

Attrition risk and replacement strategy

Attrition is rarely uniform, but an annual rate is a useful baseline. Test higher attrition to reflect market pressure, manager changes, or seasonal exits. If you plan to backfill every departure, choose replacement mode to keep operational capacity stable. If you accept net reductions, choose net adds and track where headcount declines create coverage risk. Document the drivers behind each attrition rate so updates stay consistent.

Cost forecasting and budget guardrails

Monthly cost uses average headcount and loaded compensation, giving a practical runway view for finance partners. Adjust salary and load to reflect blended pay, benefits, taxes, and allowances. Use the scenario swing to set guardrails: best case for stretch hiring, base for budget, and worst for contingency. Export results to support budget reviews and headcount approvals. Review variance monthly, then recalibrate hires or pay assumptions before costs compound.

Productivity ramp and delivery expectations

New hires contribute gradually. Ramp months and ramp start productivity capture onboarding, training, and tooling time. If you shorten ramp, productive FTE rises faster but may be unrealistic. If you lengthen ramp, costs may arrive before output. Align ramp inputs with your enablement plan, manager bandwidth, and role complexity to set credible delivery expectations. Align targets across business units.

FAQ

Frequently asked questions

What does the scenario swing change?

It adjusts best and worst outcomes by scaling hires and attrition around your base plan, helping you stress‑test staffing and budget sensitivity.

How is monthly attrition estimated?

The calculator converts your annual attrition rate to a monthly rate and applies it to the month’s starting headcount, then rounds to whole employees.

When should I use “Replace attrition” mode?

Use it when you intend to backfill departures automatically, so operational capacity stays steady while planned hires represent net growth.

How should I choose ramp months and start productivity?

Base them on your onboarding and enablement timeline. Longer ramps fit complex roles, new systems, or limited manager bandwidth; shorter ramps fit repeatable work.

Is the cost number a full budget?

It is a planning estimate using average headcount and loaded compensation. Add recruiting fees, bonuses, equity, contractors, and severance for a complete budget.

Can I share results with stakeholders?

Yes. Use the CSV export for analysis in spreadsheets and the PDF export for review meetings, approvals, and documentation.