A common question that I answer for clients on a daily basis is how much time they will serve before becoming eligible for Parole. The usual locations for Criminal Law questions are usually found in the Code of Criminal Procedure or Penal Code. However, most parole related answers are usually found in the Texas Government Code.
Except as provided by 508.146 (Medically Recommended Intensive Supervision), any other inmate is eligible for release when the inmate's actual calendar time served plus good conduct time equals 1/4 of the sentence imposed or 15 years, whichever is less.
Texas Government Code 508.145(f)
42A.054(a)/3G offenses (other than capital murder)
Offenses where there is a finding of deadly weapon
20A.03-Continuous Trafficking of persons
71.02 Engaging in Organized Criminal Activity
71.023-Directing Activities of Criminal Street Gangs
These offenders are not eligible for release on parole until the inmate's actual calendar time served, without consideration of good time equals 1/2 of the sentence or 30 calendar years, whichever is less, but in no event is the inmate eligible for release in less than 2 calendar years.
Texas Government Code 508.145(d)
Drug Free Zones
An inmate serving a sentence for which the punishment is increased under 481.134 (H&S Code), is not eligible for release on parole until the actual calendar time served, without consideration of good conduct time, equals 5 years or the term to which the inmate was sentenced, whichever is less.
Texas Government Code 508.145(e)
12.42(c)(2)-Repeat Sex Offenders
Texas Government Code 508.145(c)
12.31(a)(1) Capital Felony committed while the inmate was younger than 18 years of age.
Texas Government Code 508.145(b)
These offenders are not eligible for parole:
Sentence of Death
Life Sentence without parole
21.02-Coninuous Sexual Abuse of Young Child
22.021(f) Agg. Sexual Assault
Texas Government Code 508.145(a)
So as you can see, an offender serving a sentence for a "non-aggravated" crime will be eligible for parole in as little at 1/8 of their sentence. That is because they combine their good time with their actual time to equal 1/4 of their sentence. Generally, inmates in good conduct standing who are assigned a job in prison receive roughly 35 days good time for each month in custody.
On the other hand, inmates who are serving a sentence for an "aggravated" crime will not accrue any good time towards their sentence. They will simply have to serve 1/2 of the sentence before parole eligibility.