How many gallons in a 7×7 hot tub?
A 7 × 7 ft hot tub holds about 334 gallons by the published-capacity estimate, in a likely range of 295 gal – 372 gal. Real 7 × 7 models list 330 to 410 gallons.
How to work it out
- Outside footprint: 49 sq ft
- Fit through 18 published tubs: 10.9 × 49 sq ft − 200 = 334 gal
- Published tubs miss that line by up to 12%: 295 gal – 372 gal
Seven by seven feet (about 84–89 in) is the most common size for a 6–7 person hard-shell hot tub. Their capacities cluster tightly, because the shells are similar: deep footwell, one lounger, five or six seats.
Adjust for your project
- Likely range
- 295 gal – 372 gal
- Outside footprint
- 49 sq ft
- Published tubs about this size
- Caldera Tarino 310 gal; Hot Spring Rhythm 330 gal; Hot Spring Flair 335 gal; Hot Spring Relay 340 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.
Square hot tubs around 7 ft
| Size | Estimated gallons | Likely range |
|---|---|---|
| 6.5 × 6.5 ft | 260 gal | 230 gal – 290 gal |
| 7 × 7 ft | 334 gal | 295 gal – 372 gal |
| 7.25 × 7.25 ft | 373 gal | 329 gal – 416 gal |
| 7.5 × 7.5 ft | 413 gal | 365 gal – 461 gal |
| 7.75 × 7.75 ft | 454 gal | 402 gal – 507 gal |
Published 7×7 capacities
Hot Spring Rhythm (84 × 84 in): 330 gal; Hot Spring Flair (84 × 84 in): 335 gal; Hot Spring Relay (84 × 84 in): 340 gal; Hot Spring Vanguard (87 × 87 in): 375 gal; Bullfrog A7L (fill line) (88 × 88 in): 368 gal; Jacuzzi J-285 (89 × 89 in): 365 gal; Caldera Geneva (89 × 89 in): 410 gal.
- Same size, different water. Seat layout changes the volume: a tub with two loungers holds less water than one with upright seats.
- Two figures. Bullfrog lists 368 gallons to the fill line and 508 gallons to the brim for its 88 in A7L. Chemical doses go by the fill line.
- Chemicals. At about 350 gallons, raising chlorine by 3 ppm takes only about 1 fl oz (30 ml) of 12.5% liquid chlorine, or about 2 fl oz of 6% bleach; spa product labels give measures per 500 gallons, so scale them down by about 30%.
- Draining. A tub this size refills from a garden hose in about 45 minutes at 7–8 gallons a minute.
Smaller and bigger: how many gallons in a 6x6 hot tub and how many gallons in an 8x8 hot tub. Then dose it with how much chlorine to add to a hot tub on first use.
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) - Liquid pool chlorine (sodium hypochlorite)Budget price
Adds chlorine without stabilizer or calcium. Strength is printed on the label — commonly 10% or 12.5% — and it weakens with age and heat, so buy it fresh.
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)
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 7.5 × 7.5 ft hot tub?
About 413 gallons (likely 365 gal – 461 gal).
How many litres in a 7×7 hot tub?
About 1,263 litres by the estimate (334 gallons).
Other common sizes
- How many gallons in a 6x6 hot tub — 260 gal
- How many gallons in an 8x8 hot tub — 454 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.