Last updated: August 2026
Every year, thousands of professionals take on a Lean Six Sigma course hoping for two things: a genuine step forward in their own career, and the confidence to deliver real results back at their organisation. The question we hear often, from delegates and from the managers who sponsor them, is a simple one: does it actually pay off, and what’s the return on investment?
Rather than answer that with a slogan, we decided to answer it with data. We analysed the 200 most recent certified Green Belt and Black Belt projects completed by our delegates between January 2025 and July 2026, looking specifically at how much money each project saved, how long it took, and how that stacks up against the cost of the training itself. Because this is the most recent data on record, it gives an up-to-date and reliable picture of what a Lean Six Sigma certification with us actually delivers, for the delegate, and for the business behind them.
Key figures at a glance
- Median saving per project: £51,200
- Average saving per project: £140,700
- Median project duration: 8 months
- 90% of projects save at least £8,500
- Green Belt course cost: £2,450 (+VAT), against a median Green Belt saving of £36,700, that’s a return on investment of roughly 15:1, typically earned back within the delegate’s very first project
(Based on 200 certified Green Belt and Black Belt projects completed between January 2025 and July 2026, most recently updated August 2026.)
The headline number, and why it isn’t the whole story
Across the 200 projects, the average saving came out at approximately £140,700. It’s an impressive figure, but it’s also a little misleading on its own. A handful of very large, high-impact projects pull that average up significantly, one facility management project alone saved £717,000.
So instead of leaning on the average, we look at the median: the point at which half of all projects landed above, and half below. That median is £51,200. This is the number that best represents what a typical project achieves, and it’s the figure we’d encourage any prospective delegate or sponsoring organisation to anchor their expectations to when calculating their own likely return on investment.
What financial benefits can you expect from a Lean Six Sigma project?
Averages and medians are useful, but what people really want to know is: “What are my chances of achieving a strong result?” Looking at all 200 completed projects, here’s how the financial benefits break down:
| Share of projects | Achieved savings of at least |
| ~90% | £8,500 |
| ~75% | £17,800 |
| ~50% (median) | £51,200 |
| ~25% | £130,300 |
| ~10% | £317,500 |
In other words, nearly every delegate who completes a certified project with us delivers a meaningful financial benefit to their organisation. One in four projects generates benefits exceeding £130,000, while the top decile exceeds £317,500.
These benefits may come from cost savings, increased revenue, improved productivity, higher capacity, or a combination of these. This is the profile of a genuinely high-upside outcome: most projects deliver solid, dependable financial value, while a meaningful minority achieve truly transformational results.
Green Belt or Black Belt, how the outcomes compare
Not every course is aimed at the same kind of problem, and the data reflects that clearly:
- Green Belt projects (130 in the dataset) had a median saving of around £36,700 – strong, fast, focused improvements, often tackling a well-defined process issue.
- Black Belt Services projects (24 in the dataset) had a median saving of around £74,500.
- Black Belt Manufacturing projects (46 in the dataset) had a median saving of around £98,800 – reflecting the larger scope and cross-functional complexity Black Belts are trained to take on.
This is exactly the pattern you’d hope to see: as the level of training and the scope of the assigned project increases, so does the financial impact. It’s a strong signal that the skills taught at each level translate directly into proportionally greater results, useful information whether you’re a delegate deciding which certification path fits your ambitions, or a manager deciding where to invest first.
What’s the return on investment?
This is the number most people searching for “Lean Six Sigma ROI” actually want: not just the saving, but the saving set against the cost of getting there.
A Green Belt course with us costs £2,450 (+VAT). Set against a median Green Belt project saving of £36,700, that works out to a return on investment of roughly 15:1, meaning the course typically pays for itself many times over within the delegate’s very first project, often inside the same 8-month median timeframe it takes to complete the certification. Put another way: the payback period for a typical Green Belt project is measured in months, not years.
Black Belt shows the same pattern, at a larger scale. A Black Belt Services course costs £3,250 (+VAT) against a median saving of £74,50, a return on investment of roughly 23:1. A Black Belt Manufacturing course costs £3,750 (+VAT) against a median saving of £98,800, a return on investment of roughly 26:1. In every case, the course fee is recovered many times over by the first certified project alone.
The examples above are based on our open enrolment course fees. For in-house programmes, pricing is structured differently depending on factors such as the number of participants, delivery format, and specific organisational requirements.
How long does a Lean Six Sigma project take?
Financial benefits are only half the story. The other question every delegate and sponsor asks is: how long until we see something back? Here, too, the data is reassuring:
- The median project duration is 8 months.
- 75% of projects are completed within 12 months.
- 90% of projects are completed within 15 months.
That means the overwhelming majority of delegates go from starting their course to delivering a certified, verified result within eight months, a timeline that fits comfortably within most annual planning cycles, and gives organisations a realistic date to point to when they ask, “when will we see this pay for itself?”
Why this matters beyond the numbers
It’s tempting to read a dataset like this purely as an ROI case for finance and operations teams. But underneath every one of these 200 projects is a person who built a new skill set, ran a real improvement project from the ground up, and can now point to a certified, quantified result on their CV. That’s what makes Lean Six Sigma different from most training investments: the value isn’t theoretical, and it isn’t just personal either. It shows up twice, once in the delegate’s own professional growth, and once on the organisation’s bottom line.
That combination is, frankly, the entire point of how we run our programmes. We pair every course with structured mentoring specifically so that delegates don’t just learn the methodology in a (virtual) classroom, they apply it to a real project, with real support, until it produces a real, measurable outcome. The numbers above are the evidence that this approach works, project after project.
What’s next
This analysis is a living picture, not a one-off report. As new delegates complete their certified projects, we’ll keep adding to the dataset, the 200 projects here reflect everything completed between January 2025 and July 2026. Looking ahead, we’ll also start sharing these kinds of figures broken down by sector, so a prospective delegate in, say, healthcare or logistics can see results specific to their field rather than an organisation-wide average.
For now, the takeaway is straightforward: across 200 independently certified projects, Lean Six Sigma consistently delivers a strong, measurable return on investment within a predictable payback period, and it does so while building real, career-defining capability in the people who carry it out.
Curious what a Green Belt or Black Belt certification could do for your career and your organisation? Explore our course programmes and see which path fits where you want to go next.
Frequently asked questions
1. How reliable are these figures if some projects saved so much more than others?
That’s exactly why we lead with the median (£51,200) rather than the average. A few very large projects pull the average up, but the median tells you what a typical delegate actually achieves, and the percentile table gives you the full spread, so you can see the realistic range of outcomes rather than a single, potentially misleading number.
2. Do these results apply to any industry, or only certain sectors?
The 200 projects span a wide range of industries, including manufacturing, logistics, financial services, healthcare, and the public sector. The figures presented here reflect the combined results across all completed projects.
We will be publishing more industry-specific insights in future articles, which you will be able to find in the Library section of our website.
3. Should I choose Green Belt or Black Belt if I want the biggest impact?
Both deliver real, measurable value, the right choice depends on the size and complexity of the problem you want to tackle. Black Belt projects tend to involve larger scope and cross-functional complexity, which is reflected in higher median savings, but Green Belt remains an excellent, faster route into delivering a certified, quantified result.
4. How long before a delegate delivers a result?
Most delegates complete their certified project within a year: the median project takes 8 months, 75% finish within 12 months, and 90% finish within 15 months. That’s a timeline that fits comfortably within a typical annual planning cycle.
About the author
Geert Brokking, Director at The Lean Six Sigma Company UK. Active for over 10 years in the world of Continuous Improvement, Geert has built a business dedicated to helping organisations and professionals put Lean Six Sigma into practice, facilitating the training, mentoring, and support structures behind results like these.
