Documentation

User guide — Warehouse Process Design Toolkit

Use one process at a time. Enter observed or standard times. Read the warnings. Copy the management brief. Then validate the result on the floor.

Recommended order

1. Warehouse Building Size — how many m² to rent or build?
2. Pallet Racking — type, height, locations and the racking block.
3. Floor Storage — what must sit on the floor, not in the steel.
4. Goods-in / Lorry Hall — marshalling, docks and yard.
5. Warehouse Capacity & FTE — can this crew hold the day?
6. Peak Capacity — does the average hide the hour that fails?
7. FTE Requirement — add absence and indirect labour.

How to enter time

• Process time is minutes per unit, not hours.
• If operating hours are already net of breaks, set break allowance to 0.
• Planned utilisation is an allowance on available time. It is not capacity utilisation.

One FTE

One person working one shift. Three people on each of two shifts = 6 FTE.

What this toolkit is not

It is not a WMS, a labour-management system, a digital twin, or an engineering certificate.

Files

• Live tools: https://www.logistics-analyzer.com/tools
• Excel pack: 25 calculators, 10 templates, 5 examples, and this documentation, downloaded from the paid account after the refund waiver
• Free calculator Excel file: warehouse-capacity-fte-calculator.xlsx

How the Excel calculators work

Blue cells are inputs. Yellow cells are workings. Green cells are outputs.

Change a blue cell and the green results recalculate. Do not type over yellow or green cells.

Percent inputs (utilisation, absence, occupancy) are real Excel percentages — enter 85% as 85% or 0.85, not 85.

Formula reference — Warehouse Process Design Toolkit

Version 1.0.0. The website engines and the Excel pack use the same identities. This page walks the free Capacity & FTE model in full. The other 24 calculators follow the same published identities in /tools and in 01-calculators of the Excel pack.

Purpose

Estimate how many people a single warehouse process needs, and whether current resources can process the daily volume.

The model is for one process at a time (for example receiving, picking, or packing). It is not a whole-warehouse simulation.

Inputs

One FTE is one person working one shift. Three people on each of two shifts = 6 FTE.

If operating hours are already net of breaks, set break allowance to 0.

Identities

gross minutes / shift     = operating hours × 60
net minutes / shift       = gross minutes / shift − break allowance
productive minutes / FTE  = net minutes / shift × planned utilisation
required minutes / day    = daily volume × process time
required FTE              = required minutes / day ÷ productive minutes / FTE
headcount / shift         = required FTE ÷ shifts
available volume / day    = current resources × productive minutes / FTE ÷ process time
theoretical max / day     = current resources × net minutes / shift ÷ process time
capacity utilisation      = daily volume ÷ available volume / day
capacity gap              = daily volume − available volume / day
additional resources      = max(0, required FTE − current resources)

Scenarios reuse the same identities at 80%, 100% and 120% of daily volume.

Worked example

Daily volume = 1,000 units

Process time = 3 minutes

Net available time = 450 minutes

Planned utilisation = 100%

required FTE = 1,000 × 3 ÷ 450 = 6.67

At 85% planned utilisation:

required FTE = 1,000 × 3 ÷ (450 × 0.85) = 7.84

With 6 current FTE:

available volume = 6 × 450 × 0.85 ÷ 3 = 765 units/day
capacity utilisation = 1,000 ÷ 765 = 130.7%
additional resources = 7.84 − 6 = 1.84 FTE

What planned utilisation is not

Planned utilisation is an allowance on available time (fatigue, walking, communication, minor disruption).

Capacity utilisation is an output: demand divided by available capacity.

They are not interchangeable. Setting planned utilisation to 100% is a ceiling, not a recommended operating target.

Limitations

• One process, average daily volume. Peaks need the peak-capacity model (paid toolkit).
• Process time is treated as constant. It does not model learning curves, mix, or congestion.
• Absence, holidays, training and indirect labour are not included in the free model.
• The model does not certify safety, layout, or industrial-engineering standards.
• Users must validate process times on the floor before using results for hiring or investment.

Test cases

Every published case lives in REFERENCE_CASES and is executed by npm test.

A calculator is not released if any of those cases fail.

Other v1 identities

FTE with absence and indirect

direct unadjusted     = volume × process time ÷ productive minutes
direct with absence   = direct unadjusted ÷ (1 − absence rate)
indirect              = direct with absence × indirect %
total                 = direct with absence + indirect

Productivity

earned hours          = units × standard minutes ÷ 60
performance           = earned hours ÷ paid hours
units per paid hour   = units ÷ paid hours

Dock capacity

theoretical slots     = docks × hours × 60 ÷ turn time
planning capacity     = theoretical slots × occupancy target
required docks        = vehicles × turn time ÷ (hours × 60 × occupancy target)

Vehicle processing

hourly arrival        = vehicles ÷ hours
hourly capacity       = resources × 60 ÷ process time
peak-hour queue       = max(0, daily vehicles × peak-hour share − hourly capacity)

Storage

effective locations   = locations × fill target
required locations    = pallets on hand ÷ fill target
days of cover         = pallets on hand ÷ daily pallet demand

Capacity gap levers

work content hours    = max(0, unit gap × process time ÷ 60)
paid OT hours         = work content hours ÷ planned utilisation
process time to close = current FTE × productive minutes ÷ demand

FTE overtime check

weekly paid hours short     = additional direct FTE × net hours / shift × working days
weekly productive hours     = additional direct FTE × productive hours / shift × working days
weekly OT hours available   = current direct FTE × OT hours / person / week

Compare paid hours with paid overtime. Do not compare productive hours with paid overtime.

Peak hour

peak-day volume       = average day × peak-day factor
peak-hour volume      = peak-day volume × peak-hour share
peak-hour FTE         = peak-hour volume × process time ÷ (60 × utilisation)

Peak-hour FTE assumes the busy hour has no break inside it. Day FTE still deducts the shift break.

Warehouse space (building / rent)

Pallet racking (SEMA-aligned planning)

frame depth           = pallet depth − front overhang − rear overhang
pallets / beam        = floor( beam length ÷ (pallet width + side clearance) )
levels                = 1 + floor( (clear height − top clearance − pallet height)
                                  ÷ (pallet height + vertical clearance + beam depth) )
positions / bay       = pallets / beam × levels
bays                  = ceil( pallets ÷ positions / bay )
double-row units      = ceil( ceil(bays ÷ bays per run) ÷ 2 )
racking depth         = double-row units × (2 × frame + flue) 
aisles                = double-row units + 1
run length            = bays per run × beam + 2 × end clearance
net area              = (racking depth + aisle depth) × run length
building area         = net area × (1 + operational uplift)

Floor stack

levels                = floor( max stack height ÷ pallet height )
positions / block     = levels × deep × lanes wide
blocks                = ceil( pallets ÷ positions / block )

Goods-in / lorry hall

marshalling positions = daily pallets × dwell hours ÷ operating hours
m² / position         = pallet width × depth × (1 + handling allowance)
docks                 = vehicles × turn time ÷ (hours × 60 × occupancy)

Building total

stock                 = stock pallets, or daily demand × days of cover
racked                = stock × racked share
floor                 = stock − racked
building m²           = racking area + floor area + marshalling + ancillary

These are planning envelopes. They are not a rack, civil or fire design.

Commercial and fleet

rate card labour hours = Σ (volume × minutes) ÷ 60
storage £ / pallet-week = allocated building (building + overhead share) × (1 + profit) ÷ pallets on hand
trucks = daily moves ÷ (hours × 60 × utilisation ÷ minutes per move)
UK cover factor = contracted hours ÷ productive hours after holiday and absence
safety stock (max) = max day × max lead − average day × average lead
UK trailer cube = 26 UK or 33 Euro on 13.6 m; min(cube, floor(payload ÷ kg))
yard moves = drop arrivals × moves/arrival + live arrivals

Assumptions guide

State assumptions explicitly. Hidden assumptions are how a clean spreadsheet becomes an indefensible meeting.

Always write down

• The unit (case, order, pallet, vehicle, line).
• Whether process time is observed, estimated or a formal standard.
• Whether hours are gross or net of breaks.
• Whether utilisation already includes absence.
• The period (average day, peak day, peak hour).
• What is excluded (indirect labour, holidays, mix, congestion).

Default modelling choices in v1

• One process, constant process time.
• One FTE = one person, one shift.
• Volume scenarios at −20% / base / +20%.
• Dock planning occupancy default 85%.
• Storage fill target default 85%.
• Absence and indirect labour are only in the FTE model, not the free calculator.

Do not stack allowances blindly

If a standard already includes rest and contingency, do not apply 85% planned utilisation on top.

If team leaders already process, do not add a 15% indirect allowance on top.

Anonymised examples

Published examples are generic. Do not paste confidential employer volumes, customer names, or internal standards into public Logistics Analyzer material.

Implementation guide

First week with a customer

1. Pick one process they already have to justify.
2. Time 20–30 cycles or use a trusted standard.
3. Run Capacity & FTE and Peak Capacity.
4. Walk the result with a supervisor before presenting it.
5. Only then open docks, storage or a full manpower model.

Presenting to management

Use the copied brief. Always include:

• The demand you used
• The process time you used
• Planned utilisation
• Required FTE and the rounded roster
• Available capacity
• The +20% case
• The single recommended lever

Do not present three levers as if they can all be taken at once.

Updating the model

When volume, mix or layout changes, change the inputs. Do not edit protected outputs to force a preferred answer.

Rolling this into a team

The individual licence is for one purchaser. Do not email the pack around a department. Team licences are not on sale yet.

Logistics Analyzer licence

This is the licence that ships with the free calculator and the paid toolkit. It is not legal advice.

Free Warehouse Capacity & FTE Calculator

You may use the free calculator for your own professional work, including internal analysis and internal presentations.

You may not resell the file, include it in a competing product, or present it as your own product.

The model is provided as-is. Logistics Analyzer is not liable for staffing, capacity, investment or safety decisions made with it.

Paid toolkit — individual licence

Individual — £79 (founding £49 for the first 25 paying customers)

One purchaser may use the toolkit for their own professional work.

Team and company licences are not on sale yet. Do not email the individual pack around a department.

The licence does not include redistribution, public templates, or using the files to deliver a competing digital product.

Confidentiality

Do not put confidential employer documents, customer data, or proprietary standards into public Logistics Analyzer materials. All published examples are anonymised and rebuilt from general industrial-engineering principles.