Each account type has different distribution rules.
Traditional IRAs & 401ks:
A distribution from a traditional IRA or 401(k) before the account owner reaches 59 1/2 causes a 10% early withdrawal penalty on the amount distributed. This is in addition to taxes owed on the amount distributed. So, for example, if you take a $10,000 distribution from your traditional IRA at age 45 then you will be subject to a $1,000 penalty and you will also receive a 1099-R from your IRA custodian and will need to report $10,000 of income on your tax returns. Once you reach age 59 1/2, the 10% early withdrawal penalty does not apply.
Roth IRAs & Roth 401ks:
Distributions of contributions to a Roth IRA are always tax-free. Regardless of age, you can always take a distribution of your Roth IRA contributions without penalty or tax.
In order to take a tax-free distribution of earnings from a Roth IRA, you must be age 59 1/2 or older and you must have had a Roth IRA for five years or longer. As long as those two criteria are met, earnings may be distributed from a Roth IRA tax free. If your funds in the Roth IRA are from a conversion, then you must have converted the funds at least 5 years ago and must be 59 1/2 or older in order to take a tax-free distribution. Amounts withdrawn before 59 ½ that comprise the Roth IRA’s earnings are subject to tax and a 10% early withdrawal penalty.
SEP IRA:
A distribution from a SEP IRA before the account owner reaches 59 1/2 causes a 10% early withdrawal penalty on the amount distributed. This is in addition to taxes owed on the amount distributed. So, for example, if you take a $10,000 distribution from your traditional IRA at age 45 then you will be subject to a $1,000 penalty and you will also receive a 1099-R from your IRA custodian and will need to report $10,000 of income on your tax returns. Once you reach age 59 1/2, the 10% early withdrawal penalty does not apply.
Coverdell ESA:
A distribution from a Coverdell ESA that is not used for a qualifying educational expense will have taxes due and a 10% Penalty. So, for example, if you take a $10,000 distribution from a Coverdell ESA and it's not used for qualifying educational expenses, you will be subject to a $1,000 penalty and you will also receive a 1099-R from your Custodian and will need to report the $10,000 as income on your tax returns.
HSA:
A distribution from a Health Savings Account that is not used for a qualifying medical expenses before the age of 65 will have taxes due and a 20% Penalty. So, for example, if you are age 50 and take a $10,000 distribution from an HSA and it's not used for qualifying medical expenses, you will be subject to a $2,000 penalty and you will also receive a 1099-R from your Custodian and will need to report the $10,000 as income on your tax returns.