What size solar cover do I need?
Covers are sold oversized on purpose. Buy up, let it relax in the sun, and trim to fit — with one important exception for above-ground pools.
Quick picks
Ranked by how well each one solves a sizing problem rather than by material.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | No photo Widest useful size range Sun2Solar 1200 Series Crystal Clear Solar Cover Stocked in the common rounds and rectangles, and easy to trim. | Most pools, most budgets — the default recommendation | |
| 2 | No photo Best for odd dimensions Robelle Blue Solar Cover Where the mainstream brands do not list your size. | Odd pool sizes where the big brands do not have your dimension | |
| 3 | No photo Above-ground: buy the matched one Intex Easy Set Solar Cover On a soft-sided pool, the brand-matched cover beats a generic round of the same nominal size. | Intex and other soft-sided above-ground pools |
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked September 2, 2026.
The rule: buy up, then cut
Solar covers are deliberately sold oversized against their nominal dimension, because the expectation is that you will trim them. That is not a defect and it is not a manufacturing tolerance — it is the design.
So when your pool falls between two listed sizes, buy the larger one. You can remove material with a pair of household scissors. You cannot add it.
Measuring, by pool shape
Rectangular
Measure the water surface, not the deck or the coping. Length and width at the widest points. If your pool is 15 ft 8 in by 31 ft 4 in, buy the 16 by 32 and trim.
Round
Measure the diameter of the water surface across the center, in two directions — pools are rarely as round as they look. Take the larger number.
Oval
Measure the long axis and the short axis of the water surface. Buy the rectangle that contains it (long axis by short axis) and cut the corners off. You will waste material and there is no way around it.
Freeform, kidney, Roman end
Measure the largest rectangle that fully contains the pool, buy that, and cut to the shape. Do it on a warm day, and follow the relaxing step below, because a cover cut cold on an irregular shape will end up short in the places you cannot fix.
Let it relax before you cut
This is the step everyone skips and it is the one that goes wrong. A cover arrives folded, often tightly and often after a warehouse in winter. Lay it out flat on the deck or the lawn on a warm day and leave it for an hour. It will settle, spread and lose its creases, and its real dimension is often a little different from the dimension it had straight out of the packaging.
Then float it on the water, let it find its own position, and trim in place leaving an inch or two of overhang. Cutting it dry to a measured line almost always produces a cover that is short somewhere.
The above-ground trap
This one catches a lot of people. An above-ground pool’s nominal diameter is measured to the outside of the frame or ring, not to the water surface. An “18-foot” Intex pool does not have an 18-foot water surface, so a generic 18-foot round cover will not sit inside the rail properly. It will either ride up over the edge or leave a gap.
For soft-sided and frame above-ground pools, buy the cover made for your pool’s brand and size, which accounts for this. More on above-ground covers.
Steps, benches and features
Cut around them rather than over them. A cover lying on a step gets walked on, and bubble film that has been walked on fails at that spot first. For a tanning ledge or a large bench, cutting a matching notch costs you a small amount of covered area and buys you years.
Working out your volume while you are there
Since you have the tape out, take the average depth too — every cost and timing calculation on this site needs your gallons:
| length (ft) x width (ft) x average depth (ft) x 7.48 | rectangular |
| diameter² x 0.785 x average depth x 7.48 | round |
| long axis x short axis x 0.785 x average depth x 7.48 | oval |
Gallons — the input every calculator on this site starts from
Average depth on a pool with a shallow and a deep end is (shallow + deep) / 2, which is close enough for heating arithmetic.
Every pick, in detail
What each one publishes, what is good and bad about it, and — the section this category usually omits — what we could not judge without owning one.
Sun2Solar 1200 Series Crystal Clear Solar Cover
The value pick, and the one whose logic actually holds up. A clear cover transmits more sunlight into the body of the pool instead of absorbing it at the surface, and 12 mil is the point where lifespan stops being the limiting factor. Bob Vila measured this and the 16-mil blue at the same 4 to 5 degrees in an hour, so you are paying less for the same measured result and giving up some years of service life.
Best for Most pools, most budgets — the default recommendation
| Thickness | 12 milThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Color | Clear | Retail listing |
| Stated lifespan | 3 to 4 years for the 12-mil clear tierSwim University's published figure for 12-mil clear covers generally. | Retail listing |
| Bubble side | Bubbles face the water | Published standard |
4 to 5 degrees F in one hour
Claimed by Bob Vila, measured across all covers in their group. Conditions: One hour under 2pm sun on 89 to 92 degree F days. Source
- Clear transmits more light into the water instead of stopping it at the surface
- 12 mil is the sweet spot: real service life without 16-mil bulk
- Cheaper than the 16-mil tier with no measured heating penalty
- Shorter published lifespan tier than 16 mil
- A clear cover shows algae and debris more obviously, which some people dislike
- Whether clear genuinely outlasts or under-lasts blue in the same thickness
- Real-world tear resistance at a pool with rough edges
- How much the clear material clouds over a season of UV
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked September 2, 2026.
Robelle Blue Solar Cover
A long-standing pool-supply brand with a wide size range and a lot of shelf presence. Treat the temperature figures attached to it the way you should treat all of them: the up-to-10-degree number that circulates for Robelle covers is a manufacturer claim being repeated by review sites that say plainly they did not verify it, and it is a cumulative figure rather than something you will see in an afternoon.
Best for Odd pool sizes where the big brands do not have your dimension
| Thickness | Sold across the 8 to 16 mil range depending on lineThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Color | Blue | Retail listing |
| Bubble side | Bubbles face the water | Published standard |
Up to 10 degrees F
Claimed by Robelle, repeated by Reviewed (USA Today). Conditions: None stated. Source
Reviewed states explicitly that it did not test these and pored over specifications and online reviews instead. This is a manufacturer claim, presented as one.
- Size range covers dimensions the bigger brands skip
- Sold at several thicknesses, so you can pick your durability tier
- The thin end of its range is not worth buying — see our thickness guide
- No published specification sheet
- Whether material quality is consistent across the thickness tiers
- Real service life against the tier averages
- How closely the finished cover matches its stated dimension
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked September 2, 2026.
Intex Easy Set Solar Cover
Made to fit Intex's own above-ground pools, which is the entire reason to buy it: on a soft-sided pool, a cover that matches the frame diameter is worth more than a thicker cover that does not. It is a thin cover and it will not last like a 12-mil blanket, but on a 5,000-gallon above-ground pool the physics are in your favor anyway, because there is far less water to move.
Best for Intex and other soft-sided above-ground pools
| Fits | Sized to Intex Easy Set and metal-frame pool diametersThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Color | Blue | Retail listing |
| Bubble side | Bubbles face the water | Published standard |
- Actually fits the pool it is made for, which most generic rounds do not
- Cheap enough to replace on the schedule a thin cover needs
- On a small pool the same sunlight moves the temperature several times faster
- Thin. Expect a season or two, not five
- Sized to Intex diameters, so it is a poor buy for anything else
- Actual thickness — Intex publishes no mil rating we could retrieve
- How it holds up to the sun in a hot climate over one full season
- Whether the fit is as close on the metal-frame pools as on the Easy Sets
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked September 2, 2026.
Questions people actually ask
What size solar cover should I buy for my pool?
How do I cut a solar cover to fit?
Why doesn't the 18-foot cover fit my 18-foot pool?
- U.S. Department of Energy pool-energy figures (evaporation share, BTU per pound evaporated, cover savings, recommended temperatures, wind effect)Recreonics, reproducing and attributing the U.S. Department of Energy · read 2026-09-02
- Water density: 62.424 pounds per cubic foot at 39.2°FU.S. Geological Survey, Water Science School · read 2026-09-02
Every URL above was fetched and returned content on the date shown. Where a figure is ours rather than somebody else’s, the arithmetic is on the page and on the methodology page. If you find an error in it, we would genuinely like to know.
Read next
Solar pool covers worth buying
Ranked on the specifications that actually differ between covers — thickness tier and published lifespan — because the only hands-on test in this category found no heating difference at all.
Solar covers for above-ground pools
Why fit matters more than thickness on an above-ground pool, and the arithmetic showing why a small pool responds several times faster to the same sunlight.
Solar covers for inground pools
Which covers suit a full-size inground pool, why handling weight outranks material at that scale, and the overnight loss math for a 16-by-32.
Solar cover reels
Why a reel is the highest-leverage buy in pool heating, and which ones to look at. Thirty seconds alone versus five minutes and a helper decides whether a cover saves anything.
Pool heating time calculator
Enter your gallons, the rise you want and your heater's rating. Handles the gas-versus-heat-pump rating trap and prints the whole calculation.