Blended Mortgage Rate (Two Loans)

blended = (bal1 x rate1 + bal2 x rate2) / (bal1 + bal2). A $300K first at 4% plus a $100K second at 8% blends to 5.00% on $400K ($1,667/mo interest) -- so keeping the 4% first and adding the 8% second beats a cash-out refinance only if the new single rate is above 5%. Shrink the second to $40K and the blend is 4.47%, close to the first, because the weighting follows the balances. A snapshot that ignores differing terms and amortization; a variable-rate second (HELOC) drifts. A comparison aid, not a payment plan; the loan documents govern.

combined = balance_1 + balance_2; blended = (balance_1 x rate_1 + balance_2 x rate_2) / combined; monthly_interest = (balance_1 x rate_1 + balance_2 x rate_2) / 1200.

Blended mortgage rate (the balance-weighted average cost of debt across two loans), by name; the actual loan documents govern.

The balance-weighted average rate is a standard weighted-average-cost-of-debt calculation; the balances and rates come from the loan statements.

Estimate. AHJ and licensed professional govern.

Field names used by the API: balance_1, rate_1, balance_2, rate_2, blended_rate, combined, monthly_interest

• Balance-weighted the blend follows the balances, so a small second hardly dilutes a big low-rate firstweighted-average cost of debt
• Snapshot ignores differing terms and amortization; a variable second drifts as its rate resetsscope of this tile
• Comparison basis keep-and-add beats a refinance only if the single new rate exceeds the blended ratecost-of-debt comparison