Pool-Fit Score: how it works
What it is: a 0 to 100 fit check for one specific pool (its size, type and depth), built only from published data. It is not a quality grade. Missing data scores zero and shows “not published”. Scores always name their pool, for example “92 / 100 for a 16 × 32 ft in-ground pool”. Method version: v1.2, October 2026.
We do not test units directly. Every scored input comes from a maker claim [C] or a named third-party measurement [M]. See Methodology.
Inputs and weights
| Input | Weight | Rule in short |
|---|---|---|
| Size headroom | 25 | Your pool against the maker’s claimed maximum, on a linear band |
| Coverage: walls and waterline | 20 | Walls 10 + waterline 10, from a maker claim or named measurement |
| Runtime by mode vs pool | 20 | Usable runtime against the minutes we assume the pool needs |
| Pool-type compatibility | 15 | Pool type 10 + depth 5 |
| Filtration | 10 | Finest filter included in the box |
| Warranty | 10 | Maker-published term |
| Recall | shown, not scored | Shown beside the score; the score is withheld if the model itself is recalled |
What can be scored: maker claims [C] from the maker’s own page, manual or spec PDF, and named third-party measurements [M] with a date. What can’t: retailer-listed specs [R] (shown and labeled, 0 points until we find a maker source), figures relayed second-hand with no stated origin, maker figures a reviewer repeats from the manual, figures from reviews published by retailers, and optional extra-cost accessories.
The three reference pools
| Chip label | Shape | Area | Longest dimension | Depth we assume |
|---|---|---|---|---|
| Small above-ground | 18 ft round | 254 sq ft | 18 ft | about 4 ft (1.2 m), flat floor |
| Mid in-ground | 16 × 32 ft rectangle | 512 sq ft | 32 ft | 3.5 to 6 ft (1.1 to 1.8 m) |
| Large in-ground | 20 × 40 ft rectangle | 800 sq ft | 40 ft | 3.5 to 8 ft (1.1 to 2.4 m) |
Assumption: the depths are ours, chosen for scoring. We have no source that any of these sizes is the most common, so we don’t call them typical. Freeform shapes, steps, ledges and pool surfaces are not modeled.
The rules, input by input
Size headroom (25 points). Ratio = pool area divided by the maker’s claimed maximum area. If the maker states a maximum length instead, the ratio is the pool’s longest dimension divided by that length. If it states both, we compute both and use the lower points.
- Ratio of 0.40 or less: 25 points.
- Ratio above 0.40 up to 1.00: 25 × (1 − (ratio − 0.40) / 0.60), so points fall in a straight line to 0.
- Ratio above 1.00, or no maximum published: 0.
Assumption: we chose 0.40 because makers’ maximum-pool figures are best-case, like their runtime claims. Full points need a claim at least 2.5 times your pool, which leaves room for wall and waterline mode, steps and battery aging. We never convert a length claim to an area or the reverse.
Effect at the 800 sq ft pool: a 1,600 sq ft claim gives a ratio of 0.50 and 20.8 points. A 2,152 sq ft claim (WYBOT C2 [C]) gives 0.37 and 25. An 860 sq ft claim would give 0.93 and 2.9. Length bites too: the Aiper Scuba S1 claims 1,600 sq ft and 50 ft in length [C]. Against the 40 ft pool the length ratio is 0.80, worth 8.3 points, and because Aiper states both, the lower score (8.3) counts.
Coverage (20 points). Walls 10 and waterline 10, each from a maker claim or a named measurement that it does the job. A named [M] finding that wall or waterline cleaning did not work halves that part to 5, and we cite it beside the score. Anonymous owner reviews never change points; we summarize them in the body text. Surface skimming is shown as a feature, not scored.
Runtime vs pool (20 points). We find a usable runtime U, using the first match:
- A named [M] measurement, floor and wall or mode not stated. If there are several, we use the lowest and show all.
- A maker figure [C] for floor, wall and waterline mode.
- A maker figure [C] for floor-only, Eco, or mode not stated, multiplied by 0.67 and flagged “floor-only claim, discounted”.
- Surface-only figures, Turbo figures, or nothing published: 0, shown as “floor/wall runtime not published”.
If several maker figures qualify at the same step, we use the lowest and show all.
Assumption, the 0.67 factor: Bob Vila reported about 2 hours per charge for the WYBOT C2, mode not stated (May 6, 2026), against WYBOT’s claim of up to 180 minutes in Eco mode [C]. 120 ÷ 180 ≈ 0.67. It is one data point, so we will review the factor once the battery data page has six or more measured models.
Assumption, minutes the pool needs (R): 60 for the small above-ground pool, 90 for the mid in-ground, 120 for the large in-ground. We anchor these to the default 2-hour cycle that corded robots publish for pools up to about 40 to 50 ft, such as the Dolphin Nautilus CC Plus [C].
Points = 20 × the smaller of 1 and U ÷ R. Corded robots get 20, labeled “corded — not battery-limited”, because cable length is already handled by size headroom.
Pool-type compatibility (15 points). Type is worth 10 and depth 5.
- The maker says the robot is for this pool type [C]: 10 points.
- The maker says it is not for this pool type: the chip reads “Not supported [C]”.
- The maker says nothing about it: see the next section.
- The maker’s own statements conflict for this pool type (one includes it, another names only the other type): the chip reads “Not scored — maker’s page conflicts”. If every maker statement includes the pool type, it counts as stated. We judge each pool type separately.
- Depth: the maker’s published depth range covers our reference depth, 5 points. Otherwise, or not published, 0.
Filtration (10 points). The finest filter included in the box: 10 µm or finer, 10; up to 50 µm, 7; up to 150 µm, 5; up to 200 µm, 3. Above 200 µm, or no µm figure, 0. A filter the maker lists in the model’s specs with no separate price counts as included, even if a box-contents list leaves it out. Filters the maker sells separately or calls optional are not scored.
Warranty (10 points). Maker-published term [C]: 3 years or more, 10; 2 years, 7; 1 year, 4; not published, 0. A retailer-listed warranty is not scored.
Rounding. We add the unrounded parts and round half up. If a guide ranks by score, ties go to the lower price, and the guide says so.
When we show no number
| Chip text | When |
|---|---|
| “Not supported [C]” | The maker explicitly says the robot is not for this pool type |
| “Not scored — maker doesn’t say” | The maker is silent on the pool type |
| “Not scored — maker’s page conflicts” | The maker’s own statements conflict for this pool type |
| “Score withheld — recalled (CPSC {recall no.})” | The model itself is under a recall. A brand’s recall on other models does not withhold the score |
| “Not scored — 3 of 6 inputs published” | Fewer than 4 of the 6 inputs have scorable data |
Why silence is not a zero. A maker that lists only “in-ground” has said nothing about above-ground, which is different from excluding it. So we don’t score it either way, and we leave the model out of above-ground shortlists. The page then says: “{Brand} doesn’t say whether the {model} suits above-ground pools — check with {Brand} before buying for one.” Every shown score carries “n of 6 inputs published”. Skimmers have no Pool-Fit Score yet, because the inputs are specific to cleaners.
Worked example: Beatbot Sora 10, 16 × 32 ft in-ground
| Input | Record value | Points |
|---|---|---|
| Size headroom | 3,229 sq ft (300 m²) [C]; ratio 512 ÷ 3,229 = 0.16, which is 0.40 or less | 25 of 25 |
| Coverage | Walls and waterline [C] | 20 of 20 |
| Runtime | 4 hours (240 min) floor, walls and waterline [C], against 90 min needed; no independent measurement found | 20 of 20 |
| Pool type and depth | Above-ground and in-ground [C], 10; depth 1.6 to 9.8 ft (0.5 to 3.5 m) [C] covers 3.5 to 6 ft, 5 | 15 of 15 |
| Filtration | 150 µm included; the up-to-3 µm basket is an extra $59.99 and is not scored | 5 of 10 |
| Warranty | 2 years [C] | 7 of 10 |
| Total | 6 of 6 inputs published | 92 / 100 |
Source: Beatbot’s Sora 10 product page (beatbot.com), checked October 15, 2026. We re-check it before each publish. Beatbot’s 5-hour figure is floor-only, so the 4-hour floor, walls and waterline figure is the one the rules use. PCWorld reported nearly five hours of cleaning (June 12, 2026) but does not say it was one charge, so it is not counted as a measurement. See the Beatbot Sora 10 page for the recall check, which sits beside the score and is not part of it.
How measured data changes a score
A named measurement replaces a maker claim. Example: for the WYBOT C2, Bob Vila’s “about 2 hours” (May 6, 2026) replaces WYBOT’s 180-minute Eco claim as the usable runtime. About 120 minutes meets the 90 minutes we assume for the mid in-ground pool and roughly matches the 120 for the large one, so in this case runtime points barely move. A measurement well below the minutes a pool needs would cut runtime points in proportion. That is how a score can fall once an independent runtime measurement exists.
What the score can’t tell you
Durability, how well the robot finds its way around real pools (hopper floors, for example), app quality and support. We don’t test units, so look to named reviewers who do, such as The Pool Nerd and Bob Vila, and check the date of each review.
Known limitation
At these three reference sizes, most current cordless robots claim enough size and runtime for the two smaller pools. The score therefore mainly separates models on coverage, published pool-type and depth data, filtration and warranty, and on size headroom at the 800 sq ft pool. Runtime points can fall once an independent measurement comes in below what the pool needs. We have not added a larger reference pool, because we have no source for how common such pools are.
Changelog
- v1.2, October 16, 2026: a new chip, “Not scored — maker’s page conflicts”, for a pool type the maker’s own statements disagree on, judged per pool type. When several maker runtime figures qualify at the same step, the lowest is used. Maker figures a reviewer repeats from the manual and figures from retailer-published reviews are never scored. A filter listed in the maker’s specs with no separate price counts as included. Weights and reference pools unchanged; the worked example still totals 92.
- v1.1, October 15, 2026: the size-headroom band changed from full points up to 80% of the maker’s claim to full up to 40%, falling in a straight line to 0 at 100%. Under v1.0 almost every model scored 25 of 25 at all three pools. Weights and reference pools unchanged.
- v1.0, October 15, 2026: initial method.
Any change to the method is logged here and on Corrections.
Keep reading: Methodology · battery data · above-ground pool robots