Calculate Child Support Calculating Debt PayoffIf you have unpaid child support debt, you can figure out how long it will take to pay it off with our Arrears Payoff Calculator. You can choose a payment and see how many months it will take until you’re paid in full, or choose a time frame and it will show you the payment you need to make to have a zero balance by the end date. The California Child Support Guideline Calculator is based on the same child support legal guidelines used in California courts, and can be used to estimate the amount of child support that may be ordered in your case. The county child support commissioner or family law judge has the final authority to determine the amount of a child support order. This calculator provides only an estimate and is not a guarantee of the amount of child support that will be ordered. Many factors may affect the amount of child support awarded. If you have any questions about the child support guidelines, you should talk with a lawyer or contact a Family Law Facilitator. Guideline Calculator Links Go to Calculator Download the Calculator User Guide Go to Family Law Facilitator List *Email your question about the Guideline Calculator *Please note, this address is only to be used to report technical problems with the website calculator. If you have questions about our programs or your specific case, please contact your local child support agency. Qualified Business Income DeductionThe Qualified Business Income Deduction calculator is an Excel tool provided by California Child Support to assist Guideline Calculator users in determining the amount of any Qualified Business Income deduction (QBID) they may need to enter in the Monthly Deduction Information section of the Guideline Calculator. The QBID calculator provides only an estimated amount based on the information entered by the user. Do not use the QBID calculator for tax return preparation or for any purpose other than support calculations. Only the original Excel tool available through this link should be relied upon by the users. Any version downloaded and presented by others may have altered formulas affecting the result. This calculator tool was developed by Ventura County Child Support Services and has been certified by an independent Certified Public Accountant.