The K-300 is a top-selling 48” professional upright, trusted by teachers, musicians, and families the world over. It features extended bass strings, reinforced composite action, a tapered soundboard, and grand piano key lengths - an enviable list of features for a piano even twice its price.
Price range: $14,095.00 through $14,395.00
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Our review
Short version: the K-300 is the first upright we’d describe as able to cover virtually any repertoire, and one of the two great 48-inch uprights in the world.
The Millennium III action is the reason. Kawai builds its action parts from ABS-Carbon, which lets them be lighter and stronger than wood and keeps them stable through humidity changes, so the touch is fast and even and stays that way. The bass is where the K-300 stands out for its size: in our view, its bass break comes closer to a European standard than anything else in its class.
Buy it if you want one upright that will take a student from first lessons to conservatory audition pieces, or an experienced player wants a serious practice instrument.
Think twice if height is the constraint: the K-200 is 45 inches tall and fits under a window or a wall-mounted TV.
Play it next to the K-200 and K-400 on our floor; the differences are easy to hear.
Stu Harrison, pianist and educator · President, Merriam Music
Action parts in ABS-Carbon, stiffer and lighter than wood, for fast, even repetition and stable regulation.
Straight-grained, quarter-sawn spruce, tapered for tone, with a 47.2-inch No. 1 bass string.
Die-cast aluminum action brackets, a steel-reinforced keyslip and five back posts.
Choosing a K
Three professional uprights from the same family, all on our Atlanta floor.
| Kawai K-300 | Kawai K-200 | Kawai K-400 | |
|---|---|---|---|
| Height | 48 in (122 cm) | 45 in (114 cm) | 48 in (122 cm) |
| Weight | 500 lb (227 kg) | 459 lb (208 kg) | 507 lb (230 kg) |
| No. 1 string | 47.2 in (1,200 mm) | 45.6 in (1,157 mm) | 47.2 in (1,200 mm) |
| Soundboard area | 1.39 m² | 1.34 m² | 1.39 m² |
| Back posts | 5 | 4 | 5 |
| Front casters | Double, brass | Single, brass | Double, brass |
| Fallboard | Dual-damping soft fall | Dual-damping soft fall | New England style, soft fall, grand-style music rack |
The bottom line: the K-200 isn’t a smaller K-300; it’s a different piano for a different room. The K-300 adds three inches, a longer bass string and five back posts. The K-400 adds a New England-style cabinet and grand-style music rack. Play all three on our Atlanta floor.
Compare
The 48-inch uprights buyers most often compare, side by side from each maker’s published specifications.
| Kawai K-300 | Yamaha U1 | Yamaha b3 | |
|---|---|---|---|
| Height | 48 in | 48 in | 48 in |
| Width × depth | 59 × 24 in | 60 × 24 in | 60 × 24 in |
| Weight | 500 lb | 502 lb | 522.5 lb |
| Action | Millennium III with ABS-Carbon | Not published | Not published |
| Soundboard | Solid spruce, tapered | Spruce | Solid spruce |
| No. 1 bass string | 47.2 in | 46.8 in | Not published |
| Back posts | 5 | 5 | 5 |
| Pedals | Damper, muffler, soft | Soft, mute, damper | Damper, muffler, soft |
| Soft-close fallboard | Yes | Yes | No |
By the numbers: the three are close on size and weight. The K-300 has the longest published No. 1 bass string and the only published composite action; the Yamaha b3 is the heaviest and the only one without a soft-close fallboard. The K-300 and U1 are the two titans of the 48-inch class, and the choice between them is musical, not a question of quality, so play the K-300 before you decide.
Specifications from Kawai and Yamaha USA, October 2026.
Buying from Merriam
An acoustic piano is a long-term relationship, so here’s what comes with one from us. Questions first? Call (888) 316-0630, 7 days a week.
The K-300 is on the floor at Merriam Pianos Atlanta, next to the K-15, K-200, K-400, K-500 AURES and K-800, so you can compare Kawai’s whole professional upright line in one visit.
Our team delivers across metro Atlanta, and our specialist piano movers deliver to the rest of the lower 48. See shipping and delivery.
Every acoustic piano includes Merriam’s Premium In-Home Setup: a preparation and tuning visit 2–8 weeks after delivery, once the piano has settled into your home.
Bought from an authorized dealer, the K-300 carries Kawai America’s full 10-year warranty, and it’s transferable.
Our technicians tune and service pianos across Georgia, so the piano you buy here is looked after here.
If an authorized US Kawai dealer advertises it for less, we’ll match it.
What’s in the box: the piano and a matching bench, delivered and set up, with an in-home tuning visit included.
The K-300 is the successor to Kawai’s K-3, which was named Acoustic Piano of the Year four years in a row by MMR’s Dealers’ Choice Awards. It’s a 48-inch professional upright with Kawai’s Millennium III action, extended keys, mahogany-core hammers with an added layer of underfelt, and a tapered soundboard of straight-grained, quarter-sawn solid spruce.
Teachers tell us that children who would once have needed a grand to practice advanced classical repertoire do it on K-series uprights. The K-300 is the model where that becomes true.
Kawai’s professional uprights, from the K-15 to the K-800. The K-300 is the 48-inch heart of the line.
ABS-Carbon action parts don’t swell and shrink with humidity, which matters in a Georgia summer.
The K-300’s Millennium III action uses ABS-Carbon, a composite made by infusing carbon fiber into Kawai’s ABS Styran. It’s stiffer and lighter than wood, so action parts can be made lighter without losing strength: the result is faster repetition, more control and an action that holds its regulation. Three die-cast aluminum action brackets keep it stable, and extended key length gives a more even response from the front of the key to the back. A steel-reinforced keyslip stops keys from rubbing or sticking when the humidity rises.
Kawai uses only straight-grained, quarter-sawn solid spruce for K-series soundboards, and tapers each one to get the most tone from it. Mahogany-core, T-stapled, double-felted hammers with an extra layer of underfelt give the K-300 a warm, round attack. Its 47.2-inch No. 1 bass string is long for a 48-inch piano, and it’s what gives the bass its depth.
48 inches tall: the classic professional upright height, with the string length to match.
A 47.2-inch No. 1 bass string, longer than the published figure for the Yamaha U1.
Kawai’s full 10-year warranty, transferable to the next owner.
The parts you don’t see are what keep a piano playing well for decades. The K-300 is built around five back posts, two contour bars and a steel-reinforced keyslip and keybed.
Prevents warping in humidity, so keys move freely and the action stays in regulation.
Closes slowly and quietly, so small fingers are safe.
The muffler pedal quiets the piano for late-night practice.
| Specification | Kawai K-300 |
|---|---|
| Size | |
| Height | 48 in (122 cm) |
| Width | 59 in (149 cm) |
| Depth | 24 in (61 cm) |
| Weight | 500 lb (227 kg) |
| Action & Keys | |
| Action | Millennium III Upright Action with ABS-Carbon |
| Action brackets | Die-cast aluminum (3) |
| Keys | Extended key length |
| Hammers | Mahogany core, T-stapled, double felted, all underfelted |
| Tone | |
| Soundboard | Solid spruce, straight-grained, quarter-sawn, tapered |
| Soundboard area | 1.39 m² |
| No. 1 string speaking length | 47.2 in (1,200 mm) |
| Structure & Cabinet | |
| Back posts | 5 |
| Contour bars | 2 |
| Keyslip and keybed | Steel-reinforced |
| Pedals | Damper, muffler, soft |
| Fallboard | Dual-damping soft fall |
| Front casters | Double, brass |
| Finishes | Polished Ebony, Satin Ebony, Polished Mahogany, Polished Snow White |
| Warranty | |
| Warranty | Kawai America full 10-year warranty, transferable (authorized dealers) |
Specifications per Kawai’s official K-300 documentation. Contact Merriam with any questions before purchase.
48 inches (122 cm). It’s 59 inches (149 cm) wide and 24 inches (61 cm) deep.
500 lb (227 kg).
The K-300 is three inches taller, with a longer No. 1 bass string (47.2 in against 45.6), a larger soundboard and five back posts against four. The K-200 suits rooms where height is limited.
Both are 48-inch professional uprights built to a very high standard. The K-300 has Kawai’s Millennium III composite action and a slightly longer published bass string. The choice is musical, so we recommend playing the K-300 before you decide.
The K-3, which was named Acoustic Piano of the Year four years in a row by MMR’s Dealers’ Choice Awards.
Yes. The K-300 AURES 2 adds a digital sound engine and muting for silent practice on headphones.
A matching bench, delivery and Merriam’s Premium In-Home Setup, which includes a preparation and tuning visit 2–8 weeks after delivery. Our team delivers across metro Atlanta, and our specialist movers deliver to the rest of the lower 48. See shipping and delivery.
Acoustic pianos aren’t returnable in most cases, but within 45 days you can exchange it once for a piano of equal or greater value. See our returns policy.
Kawai America’s full 10-year warranty, which is transferable, when the piano is bought from an authorized dealer.
Yes. The K-300 comes with a matching bench.
Yes. If you find the K-300 advertised for less by an authorized US Kawai dealer, send us the link and we’ll match it.
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