String Instrument Sizing Guide
Find the right size violin, viola, cello or double bass.
Choosing the right size matters for comfort, posture and technique — but it doesn't need to be complicated. This guide gives you a reliable starting point. If your child falls between two sizes, choose the smaller one: an instrument that's too large is harder to control and can cause strain, while a slightly smaller one is easier to play. And if you're unsure, just ask us.
Violin
How to measure:have your child stand naturally, then extend their left arm straight out to the side with the palm facing up — roughly the angle they'd hold a violin at. Measure from the base of the neck to the centre of the palm. It's worth measuring twice, since children often bend their arm slightly or hyperextend it without realising.
Violin/viola arm measurement
Recommended size: 800 × 600px
Viola
Violas are described by body length in inches rather than fractions, but sizing works from the same arm-length measurement as violins — and the fractional viola sizes correspond directly to violin sizes. Use the same measuring method (left arm extended, palm up, base of neck to centre of palm), then match against the table below.
Any viola 14" or under is considered a fractional size — these are for growing players and follow the violin sizing above. From 15" upwards, all violas are considered full size, and the choice between 15", 15.5", 16" and 16.5" is about the player's comfort and preference rather than their measurements. Larger violas produce a deeper, richer tone but ask more of the player's reach; many players move up or down half an inch at different points in their playing life, and there's no single “correct” adult size.
Cello
Cellos are sized on height, arm length and finger span — measured from the tip of the index finger to the tip of the little finger with the left hand comfortably spread.
Seated cello position
Recommended size: 800 × 600px
Correct fit when seated: the cello rests against the middle of the chest, the lowest tuning peg sits just below the left ear, the lower corners sit just above the inside of the knees, both ends of the fingerboard are reachable comfortably, and the shoulders stay relaxed with no stretching or hunching.
Double Bass
Double basses are sized on height and physical fit rather than a strict measurement chart. A 3/4 double bass is the standard adult size — when people say “full size” for a double bass, they almost always mean 3/4. Genuine 4/4 basses are uncommon and aren't part of our hire fleet.
Standing double bass position
Recommended size: 600 × 800px
Correct fit when standing: the nut at the top of the fingerboard sits at about eyebrow height, the bridge sits roughly level with the large knuckles of the right hand when the arm hangs naturally, first position is reachable without lifting or straining the shoulder, and the endpin can be adjusted to fine-tune the height.
Growing players need growing instruments
Children move through several sizes as they grow. Hiring means starting with the right fit and moving up whenever they need to — no fees, no limits, and no buying a new instrument at every stage. Size swaps are always free, subject to the size being available.
Frequently asked questions
My child measures between two sizes — which do I choose?
Choose the smaller size, unless your teacher says otherwise. An instrument that's a touch small is easier to play than one that's too big.
Is my child's age enough to pick a size?
No — children of the same age can vary widely in arm length and build, so a measurement is always a better guide than age alone.
How do I know when the next size is needed?
Your child's teacher often notices first. Between lessons, watch for cramped hand positions, hunching over the instrument, or difficulty reaching comfortably.
How long does a child usually stay on one size?
Around 18 months to two and a half years, though every child grows at their own pace.
Can we swap to a bigger size later?
Yes — whenever your child needs the next size, just bring the instrument in and we'll swap it. There's no fee and no limit on how many times you swap; we just need the size you need to be in stock at the time. It's one of the main advantages of hiring while a child is growing.
Still unsure?
Send us the measurements or check with the player's teacher — we'll make sure the instrument is right before it's prepared.