The following are recommended gauges for the different early bowed string instruments. Your own preference is very subjective. It is possible to calculate an "optimum" set of gauges for your instrument, but many people prefer heavier or lighter gauges to suit their climate, bow or personal preference. It is by no means an exact science.
The following typical gauges are for plain gut strings only, and do not include overwound strings. If you play at A440 or have a large instrument, you would look for a thinner gauge than if you play at A415 or A392 or have a small instrument.
120cm is single length for bass viol or cello
120cm is double length for treble viol or violin
90cm is a good length for tenor viol, or 180cm for double length
70-90cm is typical for viola, single length
The above lengths refer to the length of the string in the packet.
No gauges have been given here, as makers do not use the same scale to market their strings. When you have decided on the sort of gauge you want for your gut strings, you can ask Saraband Music to check the different recommendations for wound strings. Some makers give light/medium/heavy; others use codes. Sometimes you will find metric measurements for plain gut strings and imperial measurements for the same maker's wound strings.
To convert from metric to imperial, divide by .05. To go from imperial to metric, multiply by .05. For example a .75mm string is equivalent to a 15 in imperial measurement, while a gauge 12 in imperial is a .60 in metric. Imperial gauges are used by Damian, Pirastro and others.
Violin (full size)
e1: .56 - .64
a2: .70 - .79 (equal tension to .82 - .86)
d3: .97 - 1.08 (equal tension to 1.12 - 1.16)
Viola (full size)
a1: .70 - .79
d2: 1.00 - 1.08
Cello (full size)
a1: 1.10 - 1.20
d2: 1.45 - 1.70
g1: 2.10 - 2.30
d2: 2.80 - 3.20
d1: .54 - .62
a2: .68 - .76
e3: .88 - .97
c4: 1.12 - 1.24
g1: .60 - .64
d2: .76 - .85
a3: 1.00 - 1.12
f4: 1.28 - 1.40
d1: .68 - .74
a2: .85 - .97
e3: 1.12 - 1.27
c4: 1.40 - 1.60