How many gallons in an 8×8 hot tub?
An “8×8” hot tub, typically about 93 in square, holds about 454 gallons by the published-capacity estimate (likely 402 gal – 507 gal). Published models list about 450 to 460 gallons.
How to work it out
- Outside footprint: 60.1 sq ft
- Fit through 18 published tubs: 10.9 × 60.1 sq ft − 200 = 454 gal
- Published tubs miss that line by up to 12%: 402 gal – 507 gal
Hot tubs sold as 8 × 8 are rarely a full 96 in; most are 91–94 in square, with seven or eight seats. They hold a third more water than a 7 × 7, which shows up in heating time and chemical doses.
Adjust for your project
- Likely range
- 402 gal – 507 gal
- Outside footprint
- 60.1 sq ft
- Published tubs about this size
- Jacuzzi J-285 365 gal; Caldera Geneva 410 gal; Jacuzzi J-385 460 gal; Cal Spas Cancun EC-849B 450 gal
- The spec sheet or manual is the best source. Some makers list two figures — to the fill line and to the brim — and the fill-line number is the one to dose with.
Large hot tubs by size
| Size | Estimated gallons | Likely range |
|---|---|---|
| 7.5 × 7.5 ft | 413 gal | 365 gal – 461 gal |
| 7.75 × 7.75 ft | 454 gal | 402 gal – 507 gal |
| 8 × 8 ft | 497 gal | 440 gal – 555 gal |
| 8.25 × 8.25 ft | 542 gal | 479 gal – 604 gal |
Published capacities in the 8 ft class
Jacuzzi J-385 (91 × 91 in): 460 gal; Cal Spas Cancun EC-849B (93 × 93 in): 450 gal; Bullfrog A8L (fill line) (94 × 94 in): 457 gal. Rectangular tubs a little longer reach 455–615 gallons (Hot Spring Grandee 455, Prism 525, Caldera Cantabria 615).
- Fill line vs brim. Bullfrog lists 457 gallons at the fill line and 620 at max fill for the A8L — a big difference. Dose by the fill line.
- Heating. Each 1°F rise in 455 gallons takes about 3,800 BTU, so a cold refill takes noticeably longer than in a 7 × 7.
- Chemicals. Spa labels written per 500 gallons apply almost as printed — scale by about 0.9.
- Weight. 455 gallons of water weighs about 3,800 lb before the tub and people — check the spec sheet for the pad or deck load your model needs.
Smaller tubs: how many gallons in a 7x7 hot tub and how many gallons in a 6x6 hot tub. For a bromine tub of this size, see how much bromine to start a hot tub.
Different size? Use the full Hot Tub Gallons Calculator.
What you’ll need
- Hot tub test strips (chlorine or bromine)Budget price
Hot tubs move faster than pools; a strip before each soak tells you whether the sanitizer is still there.
See options on Amazon (opens in a new tab) - Hot tub coverPremium price
A good cover keeps heat in and debris out. A waterlogged cover loses most of its insulation.
See options on Amazon (opens in a new tab) - Bromine tablets (BCDMH)Budget price
The usual hot tub bromine for a floater or feeder. Bromine holds up better than chlorine in hot water.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How many gallons in a true 8 × 8 ft (96 in) hot tub?
About 497 gallons by the estimate (likely 440 gal – 555 gal).
How many gallons in an 8 × 7 ft rectangular hot tub?
About 410 gallons (likely 362 gal – 458 gal).
Other common sizes
- How many gallons in a 7x7 hot tub — 334 gal
- How many gallons in a 6x6 hot tub — 260 gal
Sources
- Hot Spring SX — manufacturer spec page (opens in a new tab) — 77 × 72 in outside, 230 gal.
- Hot Spring Excursion — manufacturer spec page (opens in a new tab) — 78 × 78 in outside, 250 gal.
- Hot Spring Monterey — manufacturer spec page (opens in a new tab) — 78 × 78 in outside, 265 gal.
- Caldera Bloom — manufacturer spec page (opens in a new tab) — 78 × 78 in outside, 265 gal.
- Caldera Tarino — manufacturer spec page (opens in a new tab) — 82 × 82 in outside, 310 gal.
- Hot Spring Rhythm — manufacturer spec page (opens in a new tab) — 84 × 84 in outside, 330 gal.
- Hot Spring Flair — manufacturer spec page (opens in a new tab) — 84 × 84 in outside, 335 gal.
- Hot Spring Relay — manufacturer spec page (opens in a new tab) — 84 × 84 in outside, 340 gal.
- Hot Spring Vanguard — manufacturer spec page (opens in a new tab) — 87 × 87 in outside, 375 gal.
- Bullfrog A7L (fill line) — manufacturer spec page (opens in a new tab) — 88 × 88 in outside, 368 gal.
- Jacuzzi J-285 — manufacturer spec page (opens in a new tab) — 89 × 89 in outside, 365 gal.
- Caldera Geneva — manufacturer spec page (opens in a new tab) — 89 × 89 in outside, 410 gal.
- Jacuzzi J-385 — manufacturer spec page (opens in a new tab) — 91 × 91 in outside, 460 gal.
- Cal Spas Cancun EC-849B — manufacturer spec page (opens in a new tab) — 93 × 93 in outside, 450 gal.
- Bullfrog A8L (fill line) — manufacturer spec page (opens in a new tab) — 94 × 94 in outside, 457 gal.
- Hot Spring Grandee — manufacturer spec page (opens in a new tab) — 100 × 91 in outside, 455 gal.
- Caldera Cantabria — manufacturer spec page (opens in a new tab) — 108 × 91 in outside, 615 gal.
- Hot Spring Prism — manufacturer spec page (opens in a new tab) — 110 × 91 in outside, 525 gal.
- Hot Spring Envoy — manufacturer spec page (opens in a new tab) — 5 seats on the same 8 ft 4 in × 7 ft 7 in footprint and 455 gal as the 7-seat Grandee.
- Hot Spring Aptos — manufacturer spec page (opens in a new tab) — Round, 6 ft 6 in diameter, 265 gal.
- CDC Healthy Swimming — Staying healthy in hot tubs (opens in a new tab) — No hotter than 104°F (40°C); chlorine at least 3 ppm or bromine 4–8 ppm.