Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Top client share
37.5%
Top 3 share
70.0%
Revenue if top client leaves
$250,000
Profit after that loss
$30,000
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter annual revenue ($).
- 2Enter largest client revenue ($).
- 3Enter top 3 clients revenue ($).
- 4Enter annual fixed costs ($).
- 5Read your top client share on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
One client at 40% of revenue is a business risk, not a win. This scores concentration and shows the revenue and runway hit if the top account walks.
Worked example
Using the values the calculator loads with:
Inputs
- Annual revenue: 400000 $
- Largest client revenue: 150000 $
- Top 3 clients revenue: 280000 $
- Annual fixed costs: 220000 $
Results
- Top client share: 37.5%
- Top 3 share: 70.0%
- Revenue if top client leaves: $250,000
- Profit after that loss: $30,000
What each field means
Inputs
- Annual revenue ($)
- The annual revenue used in the calculation, measured in $. Starts at 400000 $ so you have a working example on load.
- Largest client revenue ($)
- The largest client revenue used in the calculation, measured in $. Starts at 150000 $ so you have a working example on load.
- Top 3 clients revenue ($)
- The top 3 clients revenue used in the calculation, measured in $. Starts at 280000 $ so you have a working example on load.
- Annual fixed costs ($)
- The annual fixed costs used in the calculation, measured in $. Starts at 220000 $ so you have a working example on load.
Results
- Top client share
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Top 3 share
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Revenue if top client leaves
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Profit after that loss
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the client concentration risk calculator work?
One client at 40% of revenue is a business risk, not a win. This scores concentration and shows the revenue and runway hit if the top account walks. The underlying maths is: Concentration = top client revenue ÷ total revenue.
What do I need to enter?
4 values: annual revenue, largest client revenue, top 3 clients revenue, and annual fixed costs. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the top client share result mean?
It is returned as a percentage and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Client Concentration Risk Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/client-concentration-risk
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/client-concentration-risk" target="_blank" rel="noopener">Client Concentration Risk Calculator — RevenueLab</a> (2026).</p>
Source: [Client Concentration Risk Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/client-concentration-risk) (2026).