The right size is the most important thing about a beginner's string instrument. Too big and the student strains, plays out of tune, and develops bad posture; too small and the tone suffers and they'll outgrow it in months. Because children grow at different rates, sizing is based on body measurements, not age — two same-age students can easily need different sizes.
You can get a reliable estimate at home with a tape measure and the charts below. We always confirm the fit in person before a rental, free of charge, because the final check is about reach and comfort, not just a number.
How to measure for violin and viola
- Have the student stand straight and extend their left arm out to the side, palm up, as if holding a violin under the chin.
- Measure from the base of the neck (where it meets the shoulder) to the middle of the left palm.
- Use the chart below to convert that arm-length measurement to a violin size.
- Confirm the student can curl their fingers comfortably over the scroll with the instrument in playing position — a slight bend in the elbow, not a locked, straining reach.
| Arm length | Violin size | Typical age (guide only) |
|---|---|---|
| Under 14" | 1/16 | 3–5 |
| 14"–15.5" | 1/10 | 4–5 |
| 15.5"–17" | 1/8 | 4–6 |
| 17"–18.5" | 1/4 | 5–7 |
| 18.5"–20" | 1/2 | 7–9 |
| 20"–22" | 3/4 | 9–11 |
| 22"+ | 4/4 (full) | 11+ / most adults |
Viola is sized by body length rather than fractions — common sizes run roughly 12", 13", 14", 15", 15.5", and 16"+, with 15"–16" being typical full sizes for teens and adults. Because viola reach is a little longer than violin, an in-person check matters even more.
How to size a cello
Cello is played seated, so fit is about height and seated reach rather than arm extension. With the student seated and the cello at proper angle, the C-string peg should sit near the left ear and the knees should cradle the lower bouts comfortably. Use height as your first estimate, then confirm seated.
| Student height | Cello size | Typical age (guide only) |
|---|---|---|
| Under 4' | 1/4 | 5–7 |
| 4'–4'6" | 1/2 | 7–11 |
| 4'6"–5' | 3/4 | 11–15 |
| 5'+ | 4/4 (full) | 15+ / most adults |
How to size a double bass
Bass is the largest string instrument and is usually started later. Most school players use a 3/4 bass — that's the standard 'full' size for orchestral playing, with 1/2 and 1/4 sizes for younger or smaller students and a true 4/4 reserved for tall adults. Fit is checked standing: with the bass upright, the nut (top of the fingerboard) should sit around eyebrow height and the player's hand should reach first position without hunching.
| Student height | Bass size |
|---|---|
| Under 5' | 1/4 |
| 5'–5'6" | 1/2 |
| 5'6"+ | 3/4 (school standard) |