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The short answer
For a single cat with the waste drawer emptied once a week, verified consumable pricing puts Litter-Robot’s liner cost between $28.60 and $104 per year depending only on which pack size you buy — the same liners, the same box, a 3.6x spread. Add a monthly carbon filter at list price ($60/yr for the 6-pack) and a Litter-Robot runs roughly $89 to $164 per year in filters and liners before litter.
PETKIT is the cheapest on waste containment if you own the Purobot Ultra, where the refill-ring system works out to roughly $24 per year on the manufacturer’s own stated numbers — but PETKIT’s trash bags and refill rings are proprietary. Petlibro’s Luma sits in the middle on liners ($26–$34/yr) and is the most expensive of the three on odor consumables, because its carbon deodorizer is a $19.99 part you cannot substitute.
Across all three brands, the box is not the expensive part. The consumables are not either. The variable you control is pack size.
Contents
- What actually counts as a consumable
- Verified price table
- Documented replacement intervals
- The annual math, shown
- Where the pack-size spread comes from
- Who locks you into proprietary consumables
- Upfront hardware price, for context
- The assumption that dominates everything
- Five-year view
- Our Verdict
- How We Researched This
- Sources
What actually counts as a consumable
Owners usually compare sticker prices and stop there. The recurring spend breaks into five buckets, and they are not equally expensive:
- Litter. By far the largest recurring cost, and the one we can compare least well — see the flag below.
- Waste liners or bags. Cheap per unit, but you buy them 50+ times a year.
- Odor consumables. Carbon filters, deodorizer packs, refill rings. Small items, monthly cadence.
- Contact parts that wear. Litter pads, sifters, seal strips, mats.
- Electricity and app subscriptions. No manufacturer in this comparison publishes a watt-hour figure or a mandatory subscription, so we do not estimate either.
[DATA NOT VERIFIED: no wattage or annual energy-consumption figure is published for the Litter-Robot 5, 4, EVO, PETKIT Purobot, or Petlibro Luma, so this article does not include an electricity line. PETKIT Care+ and Whisker+ memberships exist but we could not confirm which features stop working without them, so we have not priced a subscription into any total.]
One more complication: litter pricing is not comparable across these brands on the data that is published. PETKIT sells its own litter in bags whose weight is not stated on the product pages we retrieved. Whisker sells GreatLitter in 20-lb, 40-lb and 60-lb subscription sizes but the pages we could reach did not expose a unit price. Petlibro does not sell litter at all. So the tables below price the hardware-consumable side precisely and mark litter as unverified rather than inventing a per-pound figure.
Verified price table
All prices below were read from the manufacturers’ own product pages on 2026-09-19. Prices change; treat this as a dated snapshot, not a standing quote.
| Item | Brand / model | Pack size | Price | Per unit |
|---|---|---|---|---|
| Waste drawer liners | Litter-Robot (any model) | 5 | $10 | $2.00/liner |
| Waste drawer liners | Litter-Robot (any model) | 25 | $25 | $1.00/liner |
| Waste drawer liners | Litter-Robot (any model) | 100 | $55 | $0.55/liner |
| Carbon filter | Litter-Robot 4 / 5 / EVO | 2 | $12 | $6.00 each |
| Carbon filter | Litter-Robot 4 / 5 / EVO | 6 | $30 | $5.00 each |
| Carbon filter (autoship) | Litter-Robot 4 / 5 / EVO | 6 | $19.50 | $3.25 each |
| Carbon filter | Litter-Robot 3 / Connect | 2 / 6 | $12 / $30 | $6.00 / $5.00 each |
| OdorTrap Packs | Litter-Robot | not stated | from $15 | [DATA NOT VERIFIED: pack count not published] |
| OdorTrap Pod (holder + 1 pack) | Litter-Robot | 1 pod | $20 | one-time |
| LitterHopper (auto-refill) | Litter-Robot 4 / 5 | 1 | $129 | one-time accessory |
| Waste drawer liners | Petlibro Luma | 1 roll | $12.99 | $0.65/liner* |
| Waste drawer liners | Petlibro Luma | 2 rolls | $19.99 | $0.50/liner* |
| Carbon deodorizer | Petlibro Luma | 1 | $19.99 | $19.99 each |
| Replacement litter mat | Petlibro Luma | 1 | $29.99 | wear item |
| Litter trapping mat | Petlibro Luma | 1 | $29.99 | wear item |
| PETKIT trash bags | PuraX / PuraMax / PuraMax 2 / Purobot Max 3 | 1 pack | $29.99 | [DATA NOT VERIFIED: roll count not published] |
| Refill ring | PETKIT Purobot Ultra | 3 pcs | $35.99 | $12.00 each |
| Refill rings | PETKIT Purobot Ultra | 6 pcs | $38.99 | $6.50 each |
| Refill rings | PETKIT Purobot Ultra | 15 pcs | $155.00 | $10.33 each |
| Odor eliminator N50 2.0 | PETKIT Purobot (bin) | 3 pcs | $19.99 | $6.66 each |
| Odor eliminator N60 | PETKIT Purobot (cylinder) | 3 pcs | $19.99 | $6.66 each |
| Litter pad Max 3.0 | PETKIT Purobot Max 3 | 1 | $39.99 | wear item |
| Litter pad Ultra 3.0 | PETKIT Purobot Ultra | 1 | $39.99 | wear item |
| Litter pad | PETKIT PuraMax | 1 | $36.99 | wear item |
| Sifter (standard or honeycomb) | PETKIT Purobot | 1 | $29.99 | wear item |
| 5-in-1 Mixed Cat Litter | PETKIT | 4 bags | $59.99 | $15.00/bag¹ |
| Clump+ Tofu Mixed Cat Litter | PETKIT | 6 bags | $69.99 | $11.67/bag¹ |
| Urine Monitor Cat Litter | PETKIT | 4 bags | $54.99 | $13.75/bag¹ |
| Crystal Litter Set | PETKIT Crystal Duo | 4 pack | $79.99 | $20.00/pack |
| GreatLitter | Litter-Robot | 20 / 40 / 60 lb | [DATA NOT VERIFIED] | — |
*Petlibro’s liner "roll of 20" count comes from the Luma accessory bundle description, which lists "Waste Drawer Liners (roll of 20)." The standalone liner product page does not restate the count.
¹Bag weight is not stated on the PETKIT product pages we retrieved, so these are per-bag prices, not per-pound prices, and cannot be converted into an annual litter cost.
Documented replacement intervals
Cost per year depends as much on cadence as on price. These are the manufacturers’ own recommendations, not our estimates.
| Consumable | Brand | Published interval |
|---|---|---|
| Waste drawer liner | Litter-Robot | Whenever you empty the drawer — Whisker says about twice weekly for two average cats, once weekly for one cat |
| Carbon filter | Litter-Robot | Every month recommended (Whisker’s FAQ allows 2–4 weeks and says frequency is up to you) |
| OdorTrap Pack | Litter-Robot | Every 2 weeks for maximum effectiveness |
| Carbon deodorizer | Petlibro Luma | Traps odors for up to 3 months (per accessory bundle copy) |
| Odor eliminator N50 2.0 | PETKIT | One piece lasts up to 1 month; 3-pack covers 3 months |
| Odor eliminator N60 | PETKIT | 45–60 days per piece; 3-pack covers 135–180 days |
| Refill ring | PETKIT Purobot Ultra | One ring packs about 10 times; the waste bin holds one cat’s waste up to 20 days |
| Waste drawer | All | Empty when full — Litter-Robot 5 up to 10 days (1 cat), 4 up to 8 days, EVO about weekly; PETKIT Max 3 up to 15 days, Max Pro 2 up to 17 days, Ultra up to 20 days |
Two things worth noticing. Litter-Robot’s liner cadence is driven by drawer volume, not by the liner itself — so a household that empties twice a week pays double what our single-cat model shows. And the Litter-Robot carbon filter is explicitly optional: Whisker states the filter is not required for the unit to function on both the Litter-Robot 3 and 4 filter pages, which makes it the single easiest line item to cut.
The annual math, shown
The calculations below use one explicit scenario: one average cat, one box, drawer emptied 52 times a year. Every input is either a verified price or a manufacturer-stated interval. Rounding is to the nearest dollar.
| Category | Litter-Robot | Petlibro Luma | PETKIT Purobot Ultra |
|---|---|---|---|
| Liners / bags per year | $29 – $104 (100-pack vs 5-pack) | $26 – $34 | ~$24 (refill rings)² |
| Odor consumable per year | $0 – $60 (filter optional) | $80 (4 deodorizers) | $46 (N60) + $80 (N50)³ |
| Litter per year | not comparable — see flag | n/a (brand sells no litter) | not comparable — see flag |
| Electricity | not published | not published | not published |
| Ballpark, excluding litter | $29 – $164 | $106 – $114 | $150³ |
²Refill ring math, using only PETKIT’s own numbers: one ring supports about 10 packings and the bin holds up to 20 days of waste for one cat, so a household running to capacity needs roughly 18 packings a year — about 1.8 rings, or $21.60 at the 3-pack’s $12.00 per ring. A single 3-pack ($35.99, 30 packings) covers about 20 months at that pace. We have annualized to $24 to stay conservative. Treat this as our arithmetic on PETKIT’s stated figures, not a PETKIT quote.
³The N50 and N60 figures come from pack prices and PETKIT’s own "lasts up to one month" / "45–60 days" statements. PETKIT recommends an N50 next to the waste bin and lets you pair an N60 in the cylinder, so running both is the full OdorVoid configuration and costs more than running N50 alone.
The honest summary of that table: the lowest-cost configuration in this comparison is a Litter-Robot running third-party bags with no carbon filter. Whisker states outright that no special bag is needed and that customers commonly use 10- to 13-gallon kitchen bags. The one caveat Whisker gives is sensor-related rather than mechanical — waste level readings can be inaccurate with a dark bag, especially when the drawer is empty. If you want both cheapest and most accurate, buy the 100-pack of white liners at $55 and stop thinking about it for two years.
Where the pack-size spread comes from
The 3.6x range in the Litter-Robot liner line is entirely pack size: $2.00 per liner in a 5-pack, $1.00 in a 25-pack, $0.55 in a 100-pack. Nothing about the liner changes between them. Whisker also notes all current-generation liners are compatible with any Litter-Robot model, and that the design changed in June 2025 — the company says reviews posted before that date refer to a discontinued design.
The same structural spread exists on PETKIT refill rings: $12.00 each in a 3-pack, $6.50 each in a 6-pack, $10.33 each in a 15-pack. That is not a typo in our table and it is not a bulk discount — the 15-pack is the worst per-unit value of the three SKUs we could price. Buying the largest pack is not automatically cheapest, so check the per-unit math before assuming.
For reference on the same principle: PETKIT’s two bag listings — "Trash Bags" and "Automatic Litter Box Trash Bag" — both came back at $29.99, and neither page states a roll count, so we cannot rank them against Litter-Robot’s liners on a per-bag basis.
Who locks you into proprietary consumables
This matters more than price, because it determines whether you can ever shop around.
| Brand | Waste containment | Odor consumable | Substitutable? |
|---|---|---|---|
| Litter-Robot 5 / 4 / EVO | Any bag that fits; 10–13 gal kitchen bags work | Carbon filter (optional), OdorTrap Packs | Yes — the unit runs without a filter and takes third-party bags |
| PETKIT Purobot Max 3 / Max Pro 2 | PETKIT-branded bags and refill-ring system | N50 and N60 | Partly — standard clumping litter is fine, but the waste system is PETKIT’s |
| PETKIT Purobot Ultra | PETKIT refill rings required | N50 and N60 | No — PETKIT states generic bags used with the ring may cause malfunctions |
| Petlibro Luma | Petlibro liners (any bag that fits is unconfirmed) | Replacement carbon deodorizer $19.99 | Largely — but no generic deodorizer is offered |
The Purobot Ultra is the clearest lock-in in the group. PETKIT states the auto waste-packing system requires its exclusive refill rings, and that using generic trash bags with the ring may lead to malfunctions. That is the trade for the hands-free sealing feature.
Set against that, Litter-Robot is the only system in this comparison where the manufacturer explicitly tells you that the consumable is optional and generic alternatives are acceptable. That is unusual enough to be worth stating plainly.
Upfront hardware price, for context
| Model | Listed price (2026-09-19) | Extended warranty |
|---|---|---|
| Litter-Robot 5 | $799 | 3 years $100 |
| Litter-Robot EVO | $599 | 3 years $100 |
| Litter-Robot 4 | [DATA NOT VERIFIED: page shows "$44/mo" financing, base price not captured] | — |
| Litter-Robot 5 Pro | [DATA NOT VERIFIED: base price not captured from product page] | — |
| PETKIT Purobot Max 3 | $399.99 (compare-at $499.99) | — |
| PETKIT Purobot Max Pro 2 | $549.99 (compare-at $599.99) | — |
| PETKIT Purobot Ultra | $799.99 (compare-at $899.99) | — |
| PETKIT Purobot Crystal Duo | $159.99 – $199.99 (as listed) | — |
| Petlibro Luma | $599.99 | 24-month warranty included |
The useful observation: a Purobot Max 3 at $399.99 with roughly $150/year of PETKIT consumables costs less over two years than a $799 Litter-Robot with $89/year of consumables, while the Litter-Robot is cheaper over five years once the hardware difference is amortized. Longer horizons favor the rechargeable-free, filter-optional design; see the five-year Litter-Robot cost model for that projection in full.
The assumption that dominates everything
One number moves the answer more than any price: how often you empty the waste drawer.
Whisker’s own published figures bracket this well. Litter-Robot 5 may need emptying once every 10 days in a one-cat household, Litter-Robot 4 once every 8 days, and EVO about once a week. PETKIT states up to 15 days for the Max 3, 17 for the Max Pro 2, and 20 for the Ultra in single-cat homes. Since liners are consumed per emptying, a machine that goes 20 days between empties uses roughly half the liners of one that goes 10 days — regardless of what the liners cost.
Two multipliers on top: more cats, and more cats per box. Whisker notes that per-cat capacity degrades when several cats share one unit, and that the cycle timer resets each time a cat re-enters.
Five-year view
Taking the verified numbers and holding the single-cat, weekly-empty assumption constant:
- Litter-Robot, 100-pack liners, no filter: about $29/year in consumables — roughly $143 over five years, or $165 if you round up to three 100-packs — plus litter.
- Litter-Robot, 100-pack liners, monthly filters at list price: about $89/year, or roughly $443 over five years — plus litter.
- Petlibro Luma: about $106–$114/year, or roughly $530–$570 over five years — plus litter.
- PETKIT Purobot Ultra: about $150/year — roughly $750 over five years — plus litter, and with no generic-bag escape hatch.
Every one of those figures excludes litter, which for most households is the largest recurring line. That is why the litter choice deserves its own analysis: best litter for automatic litter boxes covers which types each machine accepts, where the cheapest compatible options are, and why a cheaper litter that jams the box costs more than the litter you avoided.
Our Verdict
Lowest consumable cost, verified: Litter-Robot, because it is the only system here whose filter is documented as optional and whose waste drawer accepts any bag that fits. Buy the 100-pack of liners at $55, skip the filter if odor is under control, and the recurring bill is under $30 a year before litter. If odor is not under control, the monthly filter adds $60 and a 6-pack bought on autoship drops that to about $39.
Cheapest waste containment per year: PETKIT Purobot Ultra — roughly $22–$24/year of refill rings on PETKIT’s own numbers — but you are buying into a proprietary loop with no third-party substitute. Price that in deliberately rather than discover it later.
Most predictable: Petlibro Luma, at roughly $26–$34/year in liners and $80/year in carbon deodorizers, with a 24-month warranty included. There is very little to optimize, and very little to get wrong.
The single best money move regardless of brand: buy the largest liner pack that lowers the per-unit price, and check the per-unit math rather than the pack size — PETKIT’s 15-pack refill rings cost more per ring than its 6-pack.
If you have not bought a box yet, the consumable economics are a tiebreaker, not the main decision. Start with best automatic litter boxes for which machine fits your cat, and keep Litter-Robot error codes and lights bookmarked for the day a sensor disagrees with you.
The two items that drive the math above: Litter-Robot Waste Drawer Liners, bought in the 100-pack, and PETKIT Refill Rings — both priced from the manufacturers’ own stores on 2026-09-19.
How We Researched This
- We read prices from manufacturer product pages on a single date (2026-09-19) so the comparison is a snapshot rather than a blend of months.
- We used each manufacturer’s own stated replacement interval rather than a rule of thumb, and we mark the two places where a copy claim and a product page disagree.
- We computed annual figures only where both a verified price and a verified interval exist, and we showed the arithmetic so you can swap in your own assumptions.
- We refused to convert PETKIT’s per-bag litter prices into a per-pound or per-year figure, because bag weight is not published, and we flagged GreatLitter’s price as unretrieved instead of estimating it.
- We did not test any unit. We have not owned or operated a Litter-Robot, PETKIT, or Petlibro box, and no figure here comes from personal use.
Read more about our standards at /how-we-research/.
Sources
- https://www.litter-robot.com/litter-robot-waste-drawer-liners.html
- https://www.litter-robot.com/waste-drawer-liners-5-pack.html
- https://www.litter-robot.com/lr-drawer-liners-25-pack-1.html
- https://www.litter-robot.com/lrii-drawer-liners-100-pack-2.html
- https://www.litter-robot.com/litter-robot-4-carbon-filters.html
- https://www.litter-robot.com/litter-robot-4-carbon-filters-6pk.html
- https://www.litter-robot.com/litter-robot-3-carbon-filters.html
- https://www.litter-robot.com/odortrap.html
- https://www.litter-robot.com/odortrap-pod.html
- https://www.litter-robot.com/faq.html
- https://www.litter-robot.com/litter-robot-5.html
- https://www.litter-robot.com/litter-robot-5-pro.html
- https://www.litter-robot.com/litter-robot-evo.html
- https://www.litter-robot.com/litter-robot-5-starter-bundle.html
- https://www.litter-robot.com/litter-robot-evo-starter-bundle.html
- https://www.litter-robot.com/litterhopper.html
- https://www.litter-robot.com/litter-robot-5-litterhopper.html
- https://www.litter-robot.com/support/article/how-much-litter-do-i-put-in-litter-robot/
- https://www.petkit.com/products/purobot-max-3-automatic-cat-litter-box
- https://www.petkit.com/products/purobot-max-pro-2-automatic-cat-litter-box-with-ai-camera
- https://www.petkit.com/products/purobot-ultra
- https://www.petkit.com/products/refill-ring
- https://www.petkit.com/products/odor-eliminator-n50
- https://www.petkit.com/products/pet-odor-eliminator-n60
- https://www.petkit.com/products/everclean-flushable-cat-litter-2-bags
- https://www.petkit.com/products.json?limit=250
- https://petlibro.com/products/luma-smart-litter-box.json
- https://petlibro.com/products/luma-waste-drawer-liners.json
- https://petlibro.com/products/luma-replacement-carbon-deodorizer.json
- https://petlibro.com/products.json?limit=250