One consistent time frame
Every plan covers the next 12 months. Enter the number of systems you expect to buy during that time, including the first one. This is a spending plan, not a prediction of how long a product will last.
What goes into the total
In symbols: P × N + I + F × K + V × J + 12 × M + S + T − D.
- P × N
- Price per system × the number you plan to buy
- I
- The first fitting and cut-in total
- F × K
- Other fitting price × number of those visits
- V × J
- Maintenance price × number of maintenance visits
- 12 × M
- Your monthly supplies estimate × 12
- S + T − D
- Annual shipping + annual tax − confirmed annual discounts
A worked example
These numbers are invented to explain the tool. They are not market averages, product recommendations or a seller quote.
| Item | Calculation | Annual cost |
|---|---|---|
| Systems | $300 × 3 | $900 |
| First fitting | $80 | $80 |
| Other fittings | $80 × 2 | $160 |
| Maintenance | $60 × 10 | $600 |
| Supplies | $20 × 12 | $240 |
| Shipping and tax | $60 + $80 | $140 |
| Total | No discount | $2,120 |
The monthly average is $176.67. It is the annual total divided by 12, not a payment schedule. Your actual spending may be uneven through the year.
Unknown does not mean zero
Leave a cost as “Not sure yet” until you have enough information. The result shows only a known-cost subtotal and a list of missing inputs. If tax is unknown in the example, the known subtotal is $2,040—not an all-in total.
Choose “Not applicable” only when you have confirmed there is no charge. Choose “Included elsewhere” when the whole cost is already covered by another expense. The tool requires you to identify that expense and prevents circular references.
If you explicitly enter zero systems, an unknown system price does not create a cost. Similarly, an explicitly zero price has zero cost even if the count is not yet known. Other unresolved costs still keep the overall plan incomplete.
Two plans, one comparison
Copy Plan A to create Plan B, then edit it independently. Both must be complete before a definite annual difference appears. With missing information, you see the two subtotals and what still needs checking instead of a claim about which option is cheaper.
The “one more system” scenario changes only the number of systems. Fitting visits, shipping and all other inputs remain unchanged. Check them separately before treating that scenario as a real plan.
Rounding and limits
Amounts are calculated in cents. The monthly average is rounded to the nearest cent, with a positive half-cent rounded up. The tool accepts USD only, amounts from $0 to $1,000,000, and whole-number counts from 0 to 1,000. These are input limits, not normal price or usage ranges.
Keep a copy
Download a CSV with values and their states, or print your plan and choose Save as PDF in your browser. There is no account or cloud copy. Refreshing or closing the tab clears your working information. Method version: 1.0.0.