Compare two litter setups over the same period, with the same number of cats and the same assumptions. The lower price at checkout may or may not remain lower after consumables. This is an arithmetic worksheet, not a price survey or product review.
Separate upfront and recurring costs
For each candidate, record the delivered price of the unit and required accessories. Then list compatible litter, waste bags, filters, any required refills, and electricity if applicable. Include a subscription only if you actually intend to use it; distinguish optional features from essential operation.
Use the product’s current manual to identify required items and replacement intervals. If an interval depends on use, label your estimate rather than presenting it as a measured fact. Do not count an included starter supply twice.
Use one consistent formula
First-year cost = upfront cost + recurring purchases during year one + other applicable costs.
For ongoing monthly comparisons, divide annual recurring costs by 12. For a pack of bags, divide the pack price by its usable bag count, then multiply by your expected bag use. Do not compare price per kilogram with price per litre as if they were the same unit.
| Illustrative cost only (USD) | Setup A | Setup B |
|---|---|---|
| Upfront unit and required accessories | $40 | $200 |
| Monthly litter | $18 | $14 |
| Monthly bags and required refills | $2 | $5 |
| Twelve months of recurring costs | $240 | $228 |
| First year, before other costs | $280 | $428 |
These are invented inputs, not current prices. Here B costs $160 more upfront and saves only $1 a month in the listed recurring costs. A simple payback calculation is 160 months, ignoring repairs, lifetime, electricity, and other differences. That long result is a useful warning against assuming that automation pays for itself.
Stress-test the comparison
Use the litter cost calculator to compare your own inputs, stress-test usage, and see cumulative costs over time.
Recalculate with recurring use 25% higher. For A, $20 × 1.25 × 12 + $40 = $340. For B, $19 × 1.25 × 12 + $200 = $485. Keep other costs separate until you have evidence for them.
Also record cleaning time and replacement-part availability, but do not invent a monetary saving for them. A setup can be worth paying more for without being cheaper.
Our decision rule: compare costs only after both options meet your cat’s needs. A low total is not a reason to compromise usable space or maintenance.
Next: check the room and usable tray dimensions.
Original worksheet, prepared October 9, 2026. Replace every sample amount with your own verified figures.