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Methodology

UK Total Employee Cost Planner methodology

This methodology explains the bounded United Kingdom employer-contribution row, loaded employee cost, productive capacity and overtime-versus-hire scenario without making a worker-status or compliance determination.
Duc Nguyen X.By Duc Nguyen X.· Founder, Margin101Last reviewed: View update historyMethodology

Educational only: Business decision support, not accounting, tax or legal advice.

Privacy: Calculations run locally; Margin101 does not receive your commercial inputs.

Update policy: Reviewed when formulas or official dependencies change.

Scope: UK small-business planning using your own assumptions.

1. Formulas and units

Productive hours per employee
Hₑ = (W − L) × (h − n)

Where

W
Paid weeks per year (weeks/year)Source: User assumption
L
Paid leave weeks (weeks/year)Source: User assumption
h
Ordinary weekly hours (hours/week)Source: Business record
n
Non-productive weekly hours (hours/week)Source: User assumption
Hₑ
Productive hours per employee (hours/year)Source: Calculated output
Total workforce cost
Cw = Nₑ × E + Nc × Cc

Where

E
Loaded employee cost (GBP/year)Source: Calculated output
Cw
Selected workforce cost (GBP/year)Source: Calculated output
Nₑ
Employee headcount (people)Source: Business record
Nc
Contractor headcount (people)Source: Business record
Cc
Annual contractor cost per contractor (GBP/year)Source: Calculated output
Total productive hours
Hw = Nₑ × Hₑ + Nc × Hc

Where

Hₑ
Productive hours per employee (hours/year)Source: Calculated output
Nₑ
Employee headcount (people)Source: Business record
Nc
Contractor headcount (people)Source: Business record
Hw
Total productive workforce hours (hours/year)Source: Calculated output
Hc
Contractor annual hours for the relevant cost or capacity term (hours/year)Source: Business record
Workforce cost per productive hour
Cph = Cw ÷ Hw

Where

Cw
Selected workforce cost (GBP/year)Source: Calculated output
Hw
Total productive workforce hours (hours/year)Source: Calculated output
Cph
Workforce cost per productive hour (GBP/hour)Source: Calculated output
Capacity gap
G = max(0, D − Hw)

Where

D
Required productive hours (hours/year)Source: User assumption
G
Capacity gap (hours/year)Source: Calculated output
Hw
Total productive workforce hours (hours/year)Source: Calculated output
max
Maximum operator (operator)Source: Calculated output
Overtime cost for gap
Co = G × Ce × Mo

Where

G
Capacity gap (hours/year)Source: Calculated output
Co
Overtime cost for the capacity gap (GBP)Source: Calculated output
Ce
Employee cost per productive hour (GBP/hour)Source: Calculated output
Mo
Overtime cost multiplier (multiplier)Source: User assumption
Whole hires required for gap
Nh = ceil(G ÷ Hₑ)

Where

Hₑ
Productive hours per employee (hours/year)Source: Calculated output
G
Capacity gap (hours/year)Source: Calculated output
ceil
Round up to the next whole unit (operator)Source: Calculated output
Nh
Whole hires required for the capacity gap (whole people)Source: Calculated output
Whole-hire cash cost for gap
Ch = Nh × (Fh + E)

Where

E
Loaded employee cost (GBP/year)Source: Calculated output
Ch
Whole-hire cash cost for the capacity gap (GBP)Source: Calculated output
Fh
Fixed cost per additional hire (GBP/hire)Source: Business record
Nh
Whole hires required for the capacity gap (whole people)Source: Calculated output
Employee annual cost
E = S + B + Cs + O

Where

S
Annual base salary (GBP/year)Source: Business record
B
Annual other cash remuneration (GBP/year)Source: Business record
O
Other annual employee on-costs (GBP/year)Source: Business record
Cs
Total employer statutory contribution (GBP/year)Source: Calculated output
E
Loaded employee cost (GBP/year)Source: Calculated output
Employer National Insurance
Cs = 12 × max(0, Q ÷ 12 − Tm) × r

Where

Q
Confirmed annual statutory contribution earnings basis (GBP/year)Source: Business record
r
Employer periodic contribution rate (decimal rate)Source: Reviewed official rule · UK 2026-27 employer National Insurance
Tm
Monthly employer threshold (GBP/month)Source: Reviewed official rule · UK 2026-27 employer National Insurance
Cs
Total employer statutory contribution (GBP/year)Source: Calculated output
max
Maximum operator (operator)Source: Calculated output
Employee cost per productive hour
Ce = E ÷ Hₑ

Where

E
Loaded employee cost (GBP/year)Source: Calculated output
Hₑ
Productive hours per employee (hours/year)Source: Calculated output
Ce
Employee cost per productive hour (GBP/hour)Source: Calculated output
Contractor annual cost
Cc = Rc × Hc + Oc

Where

Cc
Annual contractor cost per contractor (GBP/year)Source: Calculated output
Hc
Contractor annual hours for the relevant cost or capacity term (hours/year)Source: Business record
Rc
Contractor hourly rate excluding tax (GBP/hour)Source: Business record
Oc
Other annual contractor costs (GBP/year)Source: Business record
Overtime-to-hire crossover
X = ceil((Fh + E) ÷ (Ce × Mo)), when X ≤ Hₑ

Where

E
Loaded employee cost (GBP/year)Source: Calculated output
Hₑ
Productive hours per employee (hours/year)Source: Calculated output
X
Overtime-to-hire crossover (hours)Source: Calculated output
ceil
Round up to the next whole unit (operator)Source: Calculated output
Ce
Employee cost per productive hour (GBP/hour)Source: Calculated output
Mo
Overtime cost multiplier (multiplier)Source: User assumption
Fh
Fixed cost per additional hire (GBP/hire)Source: Business record

Money inputs and outputs use GBP. Rates, margins, utilisation and buffers are entered as percentages and converted to decimal values for calculation.

2. Worked example

Input assumptions

The worked United Kingdom fixture starts with £60,000.00 annual salary and £7,000.00 of user-entered other on-costs. Where MyFutureFund applies, the example confirms an active payroll instruction; the live default remains unconfirmed.

Calculation and outputs

Example

The worked United Kingdom fixture starts with £60,000.00 annual salary and £7,000.00 of user-entered other on-costs. Where MyFutureFund applies, the example confirms an active payroll instruction; the live default remains unconfirmed.

Total workforce cost
£243,498.80
Total productive hours
4,555.2 hours
Workforce cost per productive hour
£53.46
Capacity gap
444.8 hours
Overtime cost for gap
£31,824.54
Whole hires required for gap
1
Whole-hire cash cost for gap
£83,249.40
Employee annual cost
£75,249.40
Employer National Insurance
£8,249.40
Employee cost per productive hour
£47.70
Contractor annual cost
£93,000.00
Overtime-to-hire crossover
1,164 hours

The exact engine returns £8,249.40 for the displayed official contribution components, £75,249.40 loaded employee cost and £243,498.80 total entered workforce cost.

Interpretation

Use the UK result as a bounded commercial workforce plan, not a worker-classification, payroll or employment-law determination.

3. Validation and boundary checks

  • Contribution components validate finite rates, floors and ceilings and retain full calculation precision.
  • Age/status/industry scope codes must match the displayed supported policy fixture.
  • Market-specific category, province, residency, wage-type and effective-period controls fail closed outside the verified fixture.
  • Annual salary must remain inside any source-versioned earnings range declared by the market adapter.
  • The statutory contribution earnings basis is validated separately from total salary.
  • Leave and non-productive time cannot eliminate all productive capacity.
  • Headcounts are whole non-negative numbers and overtime multiplier cannot be below 1.
  • A capacity gap is covered by the ceiling of gap hours divided by one employee’s productive capacity; no-gap scenarios require zero hires.
  • Unsupported policy scope fails closed instead of falling back to a global percentage.

4. Assumptions and source classification

  • Category A employee, 2026–27 tax year
  • All contribution and threshold dates match the displayed source version.
  • The automatic National Insurance row applies to confirmed category A earnings only.
  • Every cost not listed as an automatic contribution component is entered by the user.
  • Productive-time, contractor, demand, overtime and hire-cost inputs use a consistent annual basis; every required hire carries one full annual loaded employee cost plus the entered fixed cost.

Official dependencies used by this planner are captured in the Margin101 evidence register and version-acknowledged in this page history. User-entered commercial assumptions remain separate from those official inputs.

5. Limitations

  • Supports evenly paid monthly earnings across 12 complete pay periods only. Directors, irregular pay, starters/leavers, bonuses, special category letters, Freeports, Investment Zones, apprentices, veterans, benefits and Employment Allowance are excluded.
  • The tool is not payroll software and does not calculate employee deductions, withholding, benefits, awards, leave liability, insurance or filing obligations.
  • The overtime-versus-hire comparison uses entered commercial costs and does not determine whether overtime or a hire is lawful or available.
  • The tool does not classify a worker or provide tax, employment, payroll or legal advice.

This is educational decision support, not tax, accounting, legal or financial advice. Check the treatment of your actual transactions under the rules that apply in United Kingdom and seek qualified advice where appropriate.

6. Update and evidence policy

Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. Registered official sources block dependent public workflows when their evidence or version acknowledgement is unavailable or invalid. Commercial inputs remain user-supplied because they vary by business and contract.

Change history

  1. : Initial public release of the planner and methodology after pre-launch calculation, content, source and interaction review.

Related reading

Guides to interpret the decision and its assumptions.

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