NC and SC late payment interest calculator

Your GC or the owner paid late? Work out the 1%-per-month interest North and South Carolina's prompt payment laws allow, with the statute linked for each step.

The job

State Project

Who is paying whom? Which payment? (NC public jobs, GC paid by the owner) Residential project of 12 or fewer units (NC) or 16 or fewer (SC), or a residential (home)builder NCDOT contract let under G.S. 136-28.1 (NC public jobs) Private owner paying with its own money, no outside lender (SC private jobs) The contract waives §§ 29-6-30 and 29-6-50 by section number in bold or underlined type (SC private jobs) Did you tell the payer about S.C. Code § 29-6-50 when you asked for payment? (SC)

Dates and amount I don't know when the GC was paid Date the GC (or the contractor above you) received payment for your work. Owner paying the GC: the date the owner received your pay request (SC), or the earliest of acceptance, completion certificate or occupancy (NC public final) Payment due date in your contract (NC public, periodic payment) Date you were paid (leave blank if you're still unpaid; SC: the date it was mailed or delivered)

Unpaid amount ($) Lower rate agreed in the contract (% a month) (optional; NC public, owner paying the GC)

Leave out amounts properly withheld (for example for defective or disputed work, or retainage). Several unpaid amounts? Run one calculation for each.

General information, not legal advice. This calculator applies the payment deadlines and the 1%-per-month interest rate in N.C. Gen. Stat. §§ 22C-3, 22C-5 and 143-134.1 and S.C. Code §§ 29-6-30 and 29-6-50, as published on ncleg.gov and scstatehouse.gov. It prorates part months at 12% per year over 365 days and doesn't compound. The statutes don't specify a day-count method, and courts or your contract may calculate differently. Amounts properly withheld (for example for defective or disputed work or retainage) don't earn interest. It doesn't cover retainage interest, attorney fees or judgment interest. Check your contract and talk to a construction attorney before demanding payment. Rules checked November 2, 2026.

Fill in the form and choose Work out interest.

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The rules this calculator applies

North Carolina

GC (or upper-tier sub) paying a sub, private jobs: pay within 7 days of receiving each periodic or final payment; interest from the eighth day at 1% per month or a fraction thereof (G.S. 22C-3 and 22C-5). Chapter 22C doesn't apply to residential contractors or residential projects of 12 or fewer units (G.S. 22C-6).
Prime paying a sub, public jobs: the same 7 days and 1% per month from the eighth day (G.S. 143-134.1(b)). NCDOT contracts let under G.S. 136-28.1 aren't covered.
Owner paying the prime, public jobs: the final balance within 45 days of acceptance, certified completion or occupancy, whichever comes first, with interest from the 46th day; periodic payments by the contract's due date, with interest from that date. The rate is 1% per month unless a lower rate is agreed (G.S. 143-134.1(a)).
Owner paying the GC, private jobs: Chapter 22C sets no deadline or interest. Your contract governs.
The 1% a month is the rate in these sections. It isn't North Carolina's general 8% legal rate (G.S. 24-1).

South Carolina

Owner paying the GC: the undisputed amount of a pay request within 21 days of receiving it; GC paying a sub: within 7 days of receiving payment, by first-class mail or delivery (S.C. Code § 29-6-30).
Late payments earn interest at 1% a month or a pro rata fraction, from the due date, but only if the payer was told about § 29-6-50 when payment was requested (S.C. Code § 29-6-50).
The chapter covers public owners too. It doesn't apply to residential homebuilders, residential projects of 16 or fewer units, or private owners whose improvements aren't financed by someone else (S.C. Code § 29-6-60).
On private jobs, the contract can set different rates and payment periods if it waives §§ 29-6-30 and 29-6-50 by section number in bold or underlined type (§ 29-6-50).

Add the South Carolina notice to every pay app

No interest is due in South Carolina unless the payer was told about § 29-6-50 at the time payment was requested. The statute doesn't give wording. A plain line like this one, in our words, on each pay request does the job:

This payment request is subject to S.C. Code § 29-6-50, which provides for interest on late payments.

How the figure is worked out

Interest = unpaid amount × 12% × days late ÷ 365, rounded to the cent. It's simple interest, never compounded. For example, if the GC received payment on September 10 and paid your $25,000 on October 20, the last on-time day was September 17, so the payment was 33 days late: $25,000 × 12% × 33 ÷ 365 = $271.23.