Standard Time is the standardized measurement of time used throughout the Galactic Commons. Dates are measured in days and years only and are written shorthand as D/YYY, where D is the day written numerically with no leading zeroes and YYY is the numerically written year.
Standard day[]
A standard day is longer than a Solar day and is further divided into hours. Time is indicated as 'tenth hour', 'eleventh hour', et cetera.
Standard year[]
A standard year - usually simply called a standard - is considerably longer than a Solar year. A standard has at least 397 standard days. Standards are divided into units of time called tendays, which are used in a similar way to weeks in Solar time. The days do not have names, but instead are referred to as 'first day', 'second day', et cetera.
Conversion to Solar years[]
In The Long Way to a Small, Angry Planet, Bear states that "about five [Solar] years" is "about three standards", making 1 solar year roughly equal to 0.6 standards.
However, in Record of a Spaceborn Few, Eyas Parata comments that Sawyer, aged 24 Solar years, would've been roughly 6 Solar years old about 13 standards ago, making 1 solar year roughly equal to 0.72 standards. This estimate can be compared to Sawyer's known ages: he died at the age of 24 Solar years around 158/307 and was 19 Solar years old in the days following the Oxomoco Disaster (128/303). This would make 1 solar year roughly equal to 0.8 standards.
Also in Record of a Spaceborn Few, Kip Madaki and his friend Ras edit Kip's Wristpatch ID data to show his "Standard date of birth" as 23/292 and his age 20 in the current year s307, making 1 Solar year equal to 0.75 standards. This conversion remains correct when compared with Kip's known ages: 11 Solar years immediately after the Oxomoco Disaster (128/303), 16 Solar years during Parts 1-6 of Record of a Spaceborn Few (158/307–c. 185/307), and the date he claims to actually turn 20 Solar years old (23/310).