What the calculator works out
The calculator compares what the device costs your practice with what it saves or brings in per case. From this it shows the monthly operating effect, the net effect per month while a loan or lease is running, the month in which the cumulative total turns positive for good (payback period), the total after five years and a table per year. Every result comes with its formula line, so you can recompute it with a pocket calculator.
The device type only changes the labels and which price fields are shown. The calculator does not fill in any prices, savings or running costs: market prices depend on the configuration, software, service contract and your negotiation, and only your own quote is a reliable basis.
The formulas
- Investment
- = purchase price(s) + one-time additional costs
- Paid at the start
- = cash: investment; loan: investment − loan amount; leasing: down payment + one-time additional costs
- Monthly loan payment
- = loan amount × i ÷ (1 − (1 + i)^−n) with i = nominal annual interest rate ÷ 12 and n = term in months; at 0 %: loan amount ÷ n
- Result per case
- = saving per case + extra revenue per case − consumables per case
- Monthly operating effect
- = cases per month × result per case + cases per month × minutes saved × hourly rate ÷ 60 − (licence + maintenance per year) ÷ 12
- Net per month during the financing
- = monthly operating effect − loan or leasing payment
- Cumulative after month k
- = − paid at the start + k × monthly operating effect − payments made up to month k (for leasing including the final payment)
- Payback period
- = first month from which the cumulative total no longer falls below 0
- 5-year total
- = cumulative after month 60
- Straight-line depreciation per year
- = purchase price(s) ÷ useful life in years
Which figures to enter
Enter amounts the way they actually burden your practice. Whether that is with or without VAT depends on whether your practice can deduct input tax; your tax adviser can tell you. Savings per case are costs you no longer have, for example impression material, impression trays, shipping, or lab fees for models, splints or temporaries you print yourself. Only enter extra revenue per case if you actually charge it; the calculator does not check whether a service may be billed.
Chair time saved only becomes money if you use the time for other billable treatment. As the hourly rate, enter your cost or revenue per treatment hour; the hourly rate calculator works it out from your figures.
For a loan, enter the nominal interest rate (Sollzins). The formula assumes equal monthly payments at the end of each month. The effective annual rate also contains fees and gives a slightly different payment; the payment in your loan agreement takes precedence. For leasing, enter the monthly payment, term, down payment and any final payment from your offer.
What the calculator does not do
This is a calculation aid, not tax, financial or business advice. It does not calculate any tax effects. The straight-line depreciation is shown for information only and is not part of the cash flow; which useful life applies for tax purposes, and whether additional costs count towards the acquisition costs, is a question for your tax adviser. The calculation runs in your browser and nothing is stored.