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Closings · Free tool

Closing delay cost calculator

Per-diem interest, a rate lock extension, storage, temporary housing and the other daily costs of a closing that slips, multiplied by the days of delay.

A lender asks for “just another week” and the agent wants a number. This tool adds up what each day of delay costs and who usually pays it. Enter the loan, the seller's payoff, the lock terms and the buyer's moving costs, and it shows the cost per day, the one-off charges and the total for the delay.

Two of the lines are real carrying costs: the interest the seller's existing mortgage accrues every day until it is paid off, and anything the buyer pays for housing or storage because they have already moved. One line is a timing shift: the buyer's per diem on the Closing Disclosure moves to a later start date rather than adding interest, so the tool shows it but flags it. The lock extension is a one-off that only applies when the delay runs past the lock.

Days of delay

How many days the closing slips. Every daily line below is multiplied by this.

Buyer's loan

Take these from the Loan Estimate or Closing Disclosure and the lender's lock agreement. The defaults are assumptions.

The buyer's loan amount from the Loan Estimate or Closing Disclosure.

Annual note rate. Per diem is loan × rate ÷ 365. On the Closing Disclosure this is the prepaid interest line, and it moves with the date.

Lenders price extensions as a fraction of a percent of the loan per period or a flat fee. Enter what your lender quoted. The 0.25% default is an assumption, not a market price.

$900.00 on this loan amount.

0 means the lock expires on the original date. The extension is charged only when the delay runs past this.

Buyer's move

Costs the buyer carries if they have already given notice, moved out or booked a mover.

Hotel or short-term rental if the buyer has already moved out.

Storage unit or a truck held over, per day.

A rebooked mover's fee.

Seller's side

The seller's existing mortgage and the cost of holding the property until it closes.

The balance on the seller's existing loan. It accrues interest every day until it is paid off at closing.

Annual rate. Payoff interest per day is balance × rate ÷ 365.

Property taxes, insurance, HOA and utilities. Monthly total ÷ 30.

Other

Anything else that runs per day, for either side.

Cost of a 7-day delay

$1,517.54

Each extra day costs $88.22. $448.77 of this is the buyer's per diem, which moves the day interest starts rather than adding interest.

Per day

Buyer's daily interest (per diem)Buyer
The per diem on the Closing Disclosure. $448.77 over 7 days, shifted, not added.
$64.11
Seller's payoff interest per daySeller
$168.77 over 7 days.
$24.11
Per day, all lines
$88.22

Charged once

Rate lock extensionBuyer
Charged: the delay of 7 days runs past the 0 days left on the lock.
$900.00
Rebooked moverBuyer
$0.00
One-off, all lines
$900.00

Who usually pays

Buyer
Per diem, lock extension, housing, storage, mover.
$1,348.77
Seller
Payoff interest, carrying costs.
$168.77
Either
Other daily costs.
$0.00
Total
$1,517.54

If the delay runs longer

DelayTotal cost
3 days$1,164.66
7 days$1,517.54
14 days$2,135.08
30 days$3,546.60

Same inputs, different day counts. The lock extension appears in the rows that run past the days left on the lock.

How this is calculated

Every default in this tool is an assumption. Replace it with the figures on the Loan Estimate or Closing Disclosure and in the lender's lock agreement.

Buyer's daily interest (per diem) is the loan amount times the annual rate, divided by 365. The CFPB's Closing Disclosure explainer describes the Prepaids section on page 2 as including the interest on the loan from the day you close to the end of that month. A later closing date changes that figure. It moves the day interest starts rather than adding interest for the life of the loan, so the tool includes the line, labels it a timing shift, and tells you how much of the total it is.

Seller's payoff interest per day is the payoff balance times the rate on the seller's existing mortgage, divided by 365. That loan accrues until it is paid off at closing, so every day of delay is a day of interest the seller carries. Our article on closing date changes lists the per-diem charge among the money items an amendment can move.

Rate lock extension is charged once, and only when the days of delay are more than the days left on the lock at the original closing date. The CFPB says rate locks are typically available for 30, 45 or 60 days, sometimes longer, and that extending may be expensive if the transaction needs more time. The CFPB does not price extensions, and neither do we. Enter the fee the lender quoted, as a percent of the loan or a flat amount. The 0.25% default is a placeholder, not a market price.

Temporary housing, storage and the rebooked mover are the buyer's costs if they have already moved out or booked a mover. Housing and storage run per day. The mover is a one-off.

Seller's carrying costs are the property taxes, insurance, HOA dues and utilities the seller keeps paying while the property is theirs. Enter the monthly total divided by 30. Other daily costs is a plain per-day amount for anything else, assigned to neither side.

The total is every daily line times the days of delay, plus the one-off charges. The who-pays split puts the per diem, lock extension, housing, storage and mover on the buyer, the payoff interest and carrying costs on the seller, and other costs on either. The 3, 7, 14 and 30 day table reruns the same inputs at those day counts. Negative or blank entries count as zero. No contract or state rule is applied: who actually pays is whatever the amendment says.

Rule sources