Demand forecasting · Medium-sized business (50 to 249 staff) · Retail and e-commerce
Demand forecasting for a mid-sized retailer
A demand forecast for a mid-sized retailer built from its own sales history and outside signals such as seasonality and weather, delivered as a dashboard that planners use each week. Forecasts by product line and store feed buying and replenishment.
Illustrative cost
£14,000 to £45,000 ex VAT
- Typical
- £26,000
- Duration
- About 11 weeks
- Effort
- 31 to 62.5 days
Illustrative estimate, not a quote. Real prices vary.
Worked out from UK freelance contractor day rates in job adverts, with no consultancy or agency margin added. Consultancies and agencies usually charge more.
Source: IT Jobs Watch. Rates read on ; costs computed on .
What is included
- Audit of two or more years of sales or bookings data
- Baseline and machine learning forecasts compared on held-out data
- Automated weekly refresh
- A planning dashboard
Deliverables
- Forecast model and accuracy report
- Weekly data pipeline
- Planning dashboard
- Model documentation
Assumptions
- At least two years of clean transaction history
- An existing BI tool or a simple hosted dashboard
- Cloud costs are paid by the client
Not included
- Automatic ordering or rota changes
- ERP replacement
Project plan
Phases run one after another, about 11 weeks in all.
| Phase | Weeks | Main tasks |
|---|---|---|
| Data audit | 3 | Extract history; Quality checks; Choose outside signals |
| Modelling | 4 | Baseline forecast; Machine learning models; Backtesting |
| Deployment | 3 | Scheduled pipeline; Monitoring |
| Dashboard and handover | 1 | Planning dashboard; Training planners |
Who does the work
Person-days per role in each phase, low and high effort.
| Phase | Role | Days (low to high) |
|---|---|---|
| Data audit | Data analyst | 3.5 to 7 days |
| Data audit | Data engineer | 3.5 to 7 days |
| Modelling | Data scientist | 11 to 21.5 days |
| Deployment | Machine learning engineer | 5.5 to 11 days |
| Deployment | Data engineer | 2 to 5.5 days |
| Dashboard and handover | Data analyst | 3.5 to 7 days |
| Dashboard and handover | Data scientist | 2 to 3.5 days |
How the cost adds up
| Role | Low (days × 25th percentile) | Typical (days × median) | High (days × 90th percentile) |
|---|---|---|---|
| Data analyst | 7 × £393 = £2,752 | 10.5 × £475 = £4,988 | 14 × £625 = £8,750 |
| Data engineer | 5.5 × £425 = £2,338 | 9 × £500 = £4,500 | 12.5 × £688 = £8,600 |
| Data scientist | 13 × £481 = £6,253 | 19 × £600 = £11,400 | 25 × £788 = £19,700 |
| Machine learning engineer | 5.5 × £500 = £2,750 | 8.25 × £564 = £4,653 | 11 × £738 = £8,118 |
| Total, rounded | £14,000 | £26,000 | £45,000 |
How these estimates are worked out
Effort: for each phase we estimate how many days each role works, as a low and a high case. These are our estimates for a typical project of this kind, not measured data.
Rates: each role's daily rate comes from UK contract job adverts over the last six months, as published by IT Jobs Watch. These are freelance contractor rates as advertised, not what was paid, and not what a consultancy or agency charges.
Low end: the low-effort days at each role's 25th-percentile rate. We use the 25th percentile, not the 10th, because the lowest effort at the cheapest rates gives a floor few buyers would ever meet.
Typical: the mid-point between low and high effort, at each role's median rate.
High end: the high-effort days at each role's 90th-percentile rate.
Totals are rounded to the nearest £500 below £10,000 and the nearest £1,000 above, and exclude VAT. Phases run one after another.
Not included:
- Software licences, model and hosting fees
- Travel and expenses
- Your own staff's time
- A consultancy's or agency's margin, overheads and risk
Real prices vary with the supplier, the state of your data and systems, how much of the work your own team does, where the work happens and how much risk the supplier carries. Consultancies and agencies usually charge more than these contractor rates, and a fixed price usually costs more than time and materials because the supplier takes the risk.
Sources
Source: IT Jobs Watch: UK contract job adverts quoting a daily rate, 6 months to 15 November 2026. Each role's page was read on . Published under CC BY-NC-SA 4.0.
| Role | IT Jobs Watch page | Rates quoted | 25th percentile | Median | 90th percentile |
|---|---|---|---|---|---|
| Data analyst | Data Analyst | 511 | £393 | £475 | £625 |
| Data engineer | Data Engineer | 1,275 | £425 | £500 | £688 |
| Data scientist | Data Scientist | 201 | £481 | £600 | £788 |
| Machine learning engineer | Machine Learning Engineer | 92 | £500 | £564 | £738 |