semkuBuild loan calculator
Plan your draws. See construction interest and the payment after completion.
US comparison model · USD · fixed rates
Monthly draw schedule
Enter each month’s additional draw, not the cumulative amount. Zero keeps a month without a draw.
| Month | Additional draw (USD) | Drawn balance | Interest-only payment |
|---|---|---|---|
| 1 | $20,000.00 | $100.00 | |
| 2 | $60,000.00 | $300.00 | |
| 3 | $120,000.00 | $600.00 |
Later months still contain amounts or unfinished entries. Restore the month count, edit those draws to zero, or explicitly remove the later rows.
Sources and model basis
CFPB — What is a construction loan?
Explains advances as construction progresses and the possibility of needing to reapply for a permanent loan. It does not guarantee conversion.
CFPB — Regulation Z, Appendix D
Part I distinguishes interest on actual advances from interest on the entire commitment. Its disclosure estimation rules do not prescribe this calculator’s monthly draw or rounding assumptions.
Section 17(c)(6) and its commentary describe multiple advances, construction interest payments and permanent financing structures.
CFPB — Mortgage interest rate and APR
Explains why APR is broader than the interest rate. The two rates entered here are nominal annual rate assumptions, not APRs.
Kneifel & Webb (2020) — NIST Handbook 135
Section 3.2.2.1, equation 3-7 (printed page 29), gives the present value of uniform end-of-year costs. Inverting that relationship and choosing monthly periods is this calculator’s derivation, not NIST approval of a loan product. Republished courtesy of the National Institute of Standards and Technology.
Calculation rules
This calculator defines a monthly comparison model for a loan charging construction interest on the amount drawn. Some contracts charge interest on the full commitment; this model does not represent those contracts.
This calculator defines D_m as the additional draw at the start of month m. B_m = Σ D_j through month m. The month-end interest-only payment is I_m = roundCent(B_m × a / 1200), where a is the nominal construction annual percentage rate. Construction interest is Σ I_m: each month is rounded to cents first, with exact halves rounded up.
This calculator defines conversion principal P = B_N. Unused borrowing capacity is excluded. There are no principal payments during construction and no interest capitalization. A zero-draw month still accrues interest on any prior balance.
This calculator defines the repayment rate r = b / 1200 and n monthly payments. The unrounded level payment is M = P / Σ(k=1..n)(1+r)^(-k); at b = 0, M = P/n. The regular payment and each month’s interest are rounded to cents, half up. The last payment, or an earlier payoff payment, clears the remaining principal plus that month’s interest. Very small loans can have a zero-cent regular payment and a larger final payment.
This calculator defines support limits of $1 billion, 1–60 construction months, 1–600 repayment months and 0–100% nominal annual rates with at most six decimal places. USD inputs accept up to two decimal places. These are calculation limits, not lending rules. Use digits, optional correctly grouped commas and a decimal point; no currency signs.
The estimates exclude taxes, insurance, fees, daily accrual, changing rates and interest reserves or capitalization. They are not APR calculations or regulatory disclosures. Actual billing and financing costs can differ. Conversion or a new permanent loan may require a new application and approval.
Frequently asked questions
- Why does moving a draw change construction interest?
- An earlier draw stays in the balance for more months. Try moving the example’s entire $120,000 draw to month 3: total construction interest falls from $1,000 to $600, while the conversion principal stays the same.
- Does an unused loan limit become repayment principal?
- No. This model converts only the total actually drawn. For example, $60,000 drawn at zero interest over 120 repayment months gives a $500 regular payment, even with a $120,000 limit.
- Will this match my lender’s bill?
- Not necessarily. Draw dates, day counts, fees, rate changes and interest on the full commitment can change the bill. Confirm your contract’s interest and conversion terms.
- Which calculator should I use for other loan questions?
- Use the interest-only calculator for a fixed principal, the loan payment calculator for a single repayment loan, or the mortgage calculator for payments including taxes and insurance.
Mortgage calculator with taxes
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Calculations run in your browser without sending the financial values you enter to the server or storing them. See “Privacy on this page” for information about access data.