Bullfrog M8 vs M9 hot tubs compared
Short answer
The Bullfrog M8 seats 9 with 2 loungers in 94 x 94 in; the M9 seats 10 with 3 loungers in 110 x 94 in. The M8 has 288 jets to the M9's 323, as the maker counts them. Both are $24,695–$30,395 (maker's M Series starting prices, Oct 2026).
| Measure |  Bullfrog M8M Series |  M9M Series |
|---|---|---|
| Lineup | ||
| Series | M Series | M Series |
| Priceas labeled under each figure | $24,695–$30,395M Series starting prices (MSRP), Oct 2026 | $24,695–$30,395M Series starting prices (MSRP), Oct 2026 |
| Size | ||
| Seats | 9 | 10 |
| Loungers | 2 | 3 |
| Length | 94" | 110" |
| Width | 94" | 94" |
| Height | 38" | 38" |
| Water | 474 gal | 566 gal |
| Dry weight | 1,024 lb | 1,209 lb |
| Filled weightwater, no people | 6,249 lb | 7,664 lb |
| Jets and pumps | ||
| Jetsas the maker counts them | 288 | 323 |
| Jet pumps | 3 | 3 |
| Electrical | ||
| Voltage | 240V (US/CAN); 230V 50 Hz export (M8D and M9T variants) | 240V (US/CAN); 230V 50 Hz export (M8D and M9T variants) |
| Amperage | 240 VAC, 60 Hz, 50 A / 240 VAC, 60 Hz, 60 A | 240 VAC, 60 Hz, 50 A / 240 VAC, 60 Hz, 60 A |
| Build and water care | ||
| Insulation | Standard | Standard |
| Shell | acrylic | acrylic |
| Ozone | Standard | Standard |
| Warranty | ||
| Shell structure | 10 years | 10 years |
| Shell surface | 7 years | 7 years |
| Equipment | 5 years | 5 years |
| Plumbing | 5 years | 5 years |
| Cabinet | 5 years | 5 years |
Verdict: The Bullfrog M8 suits buyers who want a smaller footprint (94 x 94 in), a lighter load on a deck (6,249 lb filled) and less water to heat and treat (474 gal). The M9 suits buyers who want room for 10, more jets (323 against 288) and a roomier shell (110 x 94 in).
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What is the difference between the Bullfrog M8 and M9?
The M8 seats 9 and the M9 10. The M8 measures 94 x 94 x 38 in and the M9 110 x 94 x 38 in. The M8 has 288 jets to the M9's 323, as the maker counts them. Both are $24,695–$30,395 (maker's M Series starting prices, Oct 2026).
Both are Bullfrog Spas hot tubs from the M Series. Every figure is the maker's own, with a dot that links the page or PDF it came from. Where the published specs differ:
Will the M8 or the M9 fit my space and deck?
The M8 is 94 x 94 in, about 61 sq ft and 38 in tall; filled, it weighs 6,249 lb, about 102 lb per sq ft before anyone gets in. The M9 is 110 x 94 in, about 72 sq ft and 38 in tall; filled, it weighs 7,664 lb, about 107 lb per sq ft before anyone gets in. Leave room around the tub for the cover lifter and the service panel, and have a builder check any deck for the filled weight plus people. See hot tub sizes, hot tub weight and what to put a hot tub on.
What electrical hookup do the M8 and M9 need?
The M8 runs on 240V (US/CAN); 230V 50 Hz export (M8D and M9T variants). The M9 runs on 240V (US/CAN); 230V 50 Hz export (M8D and M9T variants). The table lists amperage and breaker as each maker prints them. A licensed electrician sizes the circuit and the GFCI protection for the model you buy. See hot tub electrical requirements.
Do the M8 and M9 carry the same warranty?
Bullfrog M8: 10 years on the shell structure, 7 years on the shell surface, 5 years on the equipment, 5 years on the plumbing and 5 years on the cabinet.
Bullfrog M9: 10 years on the shell structure, 7 years on the shell surface, 5 years on the equipment, 5 years on the plumbing and 5 years on the cabinet.
Read the warranty card before you sign: labor after year one, travel charges, and whether coverage moves to a second owner. The hot tub warranty comparison lines up every brand.
What do the M8 and M9 sell for?
Bullfrog Spas posts only a series range for the M8 and M9: $24,695–$30,395 (maker's M Series starting prices, Oct 2026). Delivery, the pad, the electrician and the cover lifter are extra. Each model's price and where it comes from: Bullfrog M8 price and Bullfrog M9 price.
Which costs less to run, the M8 or the M9?
The M8, by 38 W on standby, about $5.05 a month. Standby is what a tub draws to hold its temperature with the cover on and nobody in it. California tests it the same way for every spa sold in the state, so it is the fairest running-cost figure we have.
The M8 draws 257 W in California's standby test (filed at 474 gallons), about 188 kWh and $34.13 a month at the U.S. average rate. 25% of the 76 filed tubs its size draw more; their median is 226 W.
The M9 draws 295 W in California's standby test (filed at 588 gallons), about 215 kWh and $39.17 a month at the U.S. average rate. 6% of the 16 filed tubs its size draw more; their median is 228 W.
Costs use the U.S. average residential rate of 18.19¢ a kWh (January to July 2026, EIA). Your own rate, climate and how often you use the jets change the bill. Hot tub running cost works it out by state, and measured standby watts lists every filed model.
What to check in the showroom
- Sit in both, dry is fine, in the seat you would use most. On a running display tub, feel the jets with the back of your hand. Seat depth and where the jets land matter more than the count.
- Climb in and out: step height and the lounger's length suit some bodies and not others.
- Ask for each model's California Energy Commission listing and the warranty card.
- Lie back in the lounger, dry is fine. If your feet don't reach the end of the footwell or your head sits low, it will not suit you.
The full spec sheets: Bullfrog M8 hot tub and Bullfrog M9 hot tub.
Still deciding? Get the price range on both.
- Bullfrog M8$24,695–$30,395M Series starting prices (MSRP)
- Bullfrog M9$24,695–$30,395M Series starting prices (MSRP)
Free price range, then one dealer.
Common questions
What is the difference between the Bullfrog M8 and M9?
The M8 seats 9 and the M9 10. The M8 measures 94 x 94 x 38 in and the M9 110 x 94 x 38 in. The M8 has 288 jets to the M9's 323, as the maker counts them. Both are $24,695–$30,395 (maker's M Series starting prices, Oct 2026). The table lists every published figure side by side.
Which is bigger, the M8 or the M9?
The M9: 110 x 94 in, about 72 sq ft, against 94 x 94 in, about 61 sq ft for the M8. The M8 holds 474 gallons and the M9 566.
Which costs less to run, the M8 or the M9?
The M8: 257 W on standby against 295 W in California's tests, about $34.13 against $39.17 a month at the U.S. average of 18.19¢ a kWh (EIA, January to July 2026). Heating fresh water and running the jets add to that.
Do the M8 and M9 have the same warranty?
Yes, on the terms the maker publishes: shell structure 10 years, shell surface 7 years, equipment 5 years, plumbing 5 years and cabinet 5 years.
How much do the M8 and M9 cost?
Bullfrog Spas posts only a series range for the M8 and M9: $24,695–$30,395 (maker's M Series starting prices, Oct 2026). Delivery, the pad and the electrician are extra.
Sources
5
- Bullfrog Spas M8 product pagemaker's specifications
- Bullfrog Spas warrantyM8 warranty terms
- Bullfrog Spas M9 product pagemaker's specifications
- California Energy Commission appliance database (spas)standby watts
- EIA Electric Power Monthly, Table 5.6.BU.S. average residential rate, 18.19¢ a kWh, January to July 2026