Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Profit per set
$71.17
Annualized return
11.69%
Net sale proceeds
$199.17
Effective cost
$128.00
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter purchase price ($).
- 2Enter discount at purchase (%).
- 3Enter years held.
- 4Enter annual appreciation (%).
- 5Enter sale fees + shipping (%).
- 6Read your profit per set on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Retired sets appreciate, but storage space and marketplace fees eat into it. See annualized return after all of that.
Worked example
Using the values the calculator loads with:
Inputs
- Purchase price: 160 $
- Discount at purchase: 20 %
- Years held: 4
- Annual appreciation: 11 %
- Sale fees + shipping: 18 %
Results
- Profit per set: $71.17
- Annualized return: 11.69%
- Net sale proceeds: $199.17
- Effective cost: $128.00
What each field means
Inputs
- Purchase price ($)
- The purchase price used in the calculation, measured in $. Starts at 160 $ so you have a working example on load.
- Discount at purchase (%)
- The discount at purchase used in the calculation, measured in %. Starts at 20 % so you have a working example on load. Accepted range: 0–60 %.
- Years held
- The years held used in the calculation. Starts at 4 so you have a working example on load.
- Annual appreciation (%)
- The annual appreciation used in the calculation, measured in %. Starts at 11 % so you have a working example on load.
- Sale fees + shipping (%)
- The sale fees + shipping used in the calculation, measured in %. Starts at 18 % so you have a working example on load.
Results
- Profit per set
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annualized return
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net sale proceeds
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Effective cost
- 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 lego set investment roi calculator work?
Retired sets appreciate, but storage space and marketplace fees eat into it. See annualized return after all of that.
What do I need to enter?
5 values: purchase price, discount at purchase, years held, annual appreciation, and sale fees + shipping. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the profit per set result mean?
It is returned as a money amount in US dollars 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. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). LEGO Set Investment ROI Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/lego-set-roi
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/lego-set-roi" target="_blank" rel="noopener">LEGO Set Investment ROI Calculator — RevenueLab</a> (2026).</p>
Source: [LEGO Set Investment ROI Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/lego-set-roi) (2026).