Calculation is client-side, income figures are never transmitted or stored.
How Tennessee Child Support Is Calculated
- Determine each parent's monthly adjusted gross income, then combine both for combined monthly adjusted gross income.
- Look up the basic child support obligation (BCSO) from the official Schedule of Basic Child Support Obligations for that combined income and number of children.
- Each parent's pro rata share equals their income divided by combined income, applied to the BCSO.
- If the paying parent (ARP) has 92 or more days of parenting time per year, a variable multiplier (days x 2/182.5) adjusts the BCSO upward, and the difference is credited against the paying parent's share to account for duplicated/transferred expenses.
- That result is compared against a schedule lookup using the paying parent's own income alone (the Self-Support Reserve, $957/month) — the LESSER of the two applies, and if the individual lookup wins, the parenting-time credit is effectively forfeited.
- Above $28,250/month combined adjusted gross income, Tennessee applies its own formula directly rather than judicial discretion.
Tennessee Child Support Worksheet Walkthrough
Example (the rule's own worked example): $1,000/month BCSO, paying parent (ARP) has 94 parenting days/year, custodial parent (PRP) has a 40% income share.
- Variable multiplier: 94 × 0.0109589 = 1.0301366.
- Adjusted BCSO: $1,000 × 1.0301366 = $1,030.14; difference from base: $30.14.
- PRP's 40% share of that difference: $12.06, credited against the ARP's 60% share ($600): $600 − $12.06 = $587.94/month, assuming this is above the Self-Support Reserve comparison.
How This Calculator Works — Formula & Constants
Source: Tennessee Department of Human Services, Child Support Guidelines (Tenn. Comp. R. & Regs. 1240-02-04) · Calcul déterministe — no AI, no arbitrary estimate.
Constants used
| Constant | Value | Source |
|---|
Formula
base_obligation = schedule_lookup(combined_income, children)
share_B = parentB_income / combined_income
total_obligation = base_obligation + childcare_cost + health_insurance_cost
obligation_B = total_obligation × share_B
Deterministic calculation based on Tennessee's official guideline schedule table. Verify against Tennessee's official calculator for a court-ready figure.
FAQ
How is child support calculated in Tennessee?
Determine each parent's monthly adjusted gross income, then combine both for combined monthly adjusted gross income. Look up the basic child support obligation (BCSO) from the official Schedule of Basic Child Support Obligations for that combined income and number of children. Each parent's pro rata share equals their income divided by combined income, applied to the BCSO. If the paying parent (ARP) has 92 or more days of parenting time per year, a variable multiplier (days x 2/182.5) adjusts the BCSO upward, and the difference is credited against the paying parent's share to account for duplicated/transferred expenses. That result is compared against a schedule lookup using the paying parent's own income alone (the Self-Support Reserve, $957/month) — the LESSER of the two applies, and if the individual lookup wins, the parenting-time credit is effectively forfeited. Above $28,250/month combined adjusted gross income, Tennessee applies its own formula directly rather than judicial discretion.
How does Tennessee's parenting time credit work?
If the paying parent (ARP) has 92 or more days of parenting time per year, Tennessee applies a "variable multiplier" — the ARP's annual parenting days times 2/182.5 — to the basic child support obligation (BCSO). The increase this produces is prorated by the custodial parent's income share and credited against the paying parent's obligation, reflecting the duplicated and transferred expenses of shared parenting time. At exactly half the year (182.5 days), this doubles the BCSO before crediting.
What is Tennessee's Self-Support Reserve, and does it cancel the parenting time credit?
The Self-Support Reserve (SSR) is 90% of the federal poverty guideline for one person — $957/month. Tennessee compares the parenting-time-credited obligation against a schedule lookup using the paying parent's own income alone; whichever is LOWER applies. If the individual-income lookup is lower, the paying parent effectively loses the parenting-time credit, since the final amount comes from the SSR comparison instead.
What happens if combined income is above $28,250/month in Tennessee?
Above $28,250/month in combined adjusted gross income, Tennessee's rule specifies its own formula directly rather than leaving it to judicial discretion: the $28,250 schedule amount plus a percentage of the income above that threshold, ranging from 6.81% for one child up to 8.66% for five or more children.
Methodology & Source
Formula model: income shares. Effective 2021-10-01, guideline version 2021-TN-v1, last reviewed 2026-07-12.
Official source: Tennessee Department of Human Services, Child Support Guidelines (Tenn. Comp. R. & Regs. 1240-02-04) (Tenn. Comp. R. & Regs. 1240-02-04).
Above $28,250/month combined adjusted gross income, Tennessee's own formula applies directly: the $28,250 schedule amount plus a percentage of income above that (6.81%-8.66% by number of children), not judicial discretion. This calculator does not model split parenting (two or more children divided between parents) or extraordinary/other statutory deviations.
Guideline figures transcribed from the primary source above and cross-checked against Tennessee's official calculator/worksheet for multiple test scenarios — see our verification methodology.