How Tennessee Calculates Child Support

Tennessee uses the Income Shares model to determine child support obligations. This page explains the guidelines, formula, and key factors.

Model Type

Income Shares (Tenn. Comp. R. & Regs. 1240-02-04)

Tennessee looks up a basic support obligation from a 563-row schedule by combined Adjusted Gross Income and number of children, then applies a continuous 'variable multiplier' keyed to the paying parent's annual parenting-time days -- a credit above 92 days, a penalty at 68 or fewer, and no adjustment in between.

Sources & Verification

Core formula verified; some gaps disclosed below

Guideline effective 2021-10-01 · last checked against the primary source 2026-09-17

Primary sources

Tenn. Comp. R. & Regs. 1240-02-04, Child Support Guidelines (October 2021 edition)Income Shares Worksheet 2021 v1.0 (official Excel/VBA calculator, incl. the Schedule tab)A Guide to Tennessee's Child Support Worksheet

What this calculator doesn't yet handle

The 563-row schedule was extracted from the Department's own published Excel/VBA worksheet (the rule PDF's own schedule table does not extract cleanly as text — rows and columns visibly misalign). Independently confirmed against the rule's own non-tabular high-income-extension paragraph (exact match on all five base figures and percentages) and fully validated for internal consistency (0 monotonicity violations across both axes), but not cross-checked cell-by-cell against a second full source the way South Carolina's schedule was.
Split parenting (each parent primary custodian of at least one child) is not implemented, consistent with every other income-shares state in this repo.
50/50 (equal, 182.5/182.5) parenting is implemented only for the pure case with no other children in the case under a different custody split; the rule's combined 50/50-plus-standard and 50/50-plus-split role-reassignment provisions are disclosed but not automated.
Judicial deviations (extraordinary education expenses, 'special expenses' exceeding 7% of the monthly BCSO, parenting-time travel costs, and the general best-interest standard) are not predicted, only disclosed.
Imputed income for a willfully unemployed/underemployed parent (a 13-factor, fact-intensive test) is not automated. The rule's own default imputation figures for 'no reliable income evidence' cases ($43,761/year male, $35,936/year female, sourced from 2016 American Community Survey data) are offered only as an optional, clearly-labeled fallback, not as an automatic substitute for a willfulness finding.
The statutory PCSO ceiling ($2,100-$5,000/month depending on number of children) is disclosed and capped in the displayed estimate, but the rebuttal path allowing a court to exceed it on proof of need is not modeled.
A child's Social Security or VA derivative benefit drawn on a parent's account — added to that parent's income, then subtracted from that parent's final award — is not implemented; this niche two-step mechanic is disclosed as unsupported.
Self-employment ordinary-and-necessary-expense reconstruction is not modeled — a single self-employment net figure is expected to be entered as-is.
No official continuous worked example (income through final dollar order) was found in Tennessee's published materials; the rule and worksheet instructions illustrate each mechanic with isolated line-level examples rather than one soup-to-nuts case, so end-to-end test fixtures are hand-constructed against the verified schedule and formulas rather than drawn from a single official source.