How Much Principal You Need to Recast
There is no national minimum for a recast. Each servicer sets its own floor on how much principal you must reduce, and the floor is the requirement most likely to sink an otherwise perfect application. A borrower who has done everything right — quote requested, funds ready, paperwork signed — can still be declined because $4,000 was not enough.
The short answer
Expect a floor somewhere between $5,000 and $10,000, or a percentage of the outstanding balance, and occasionally both. Jumbo loans often carry higher floors. Ask your servicer for the exact figure in writing before you plan anything, because the number is not published consistently and cannot be inferred from your neighbour's experience.
The good news: the floor is one of the few recast requirements that is entirely within your control. If you cannot meet it, you can usually decide not to recast rather than being told no.
Why a minimum exists at all
A recast is manual work: intake, verification, re-amortisation, a new schedule, an escrow re-analysis and a statement update. Servicers price that work by exception, and a $2,000 principal reduction on a $400,000 loan produces a payment change so small that the administrative cost exceeds any plausible benefit to the borrower.
The floor is therefore a filter on requests that would generate complaints. It is not a credit judgement, and it is not negotiable — but it is knowable, which is more than can be said for most of the process.
Flat figure, percentage, or both
Flat figure. The most common form. A stated dollar amount that the principal reduction must meet or exceed.
Percentage of balance. Some servicers express the requirement as a share of the outstanding principal — a figure that scales with the loan and is therefore larger on bigger balances.
Both. The strictest version: you must clear the flat floor *and* the percentage. On a $600,000 loan, a 1% requirement is $6,000, which may sit above a $5,000 flat floor and become the binding constraint.
Ask which form applies, and if it is a percentage, confirm whether it is calculated on the balance before or after the reduction. The difference is small but it decides marginal cases.
Why jumbo loans are different
Jumbo loans are often held in portfolio by the originating bank rather than sold to an agency, which makes recasting more likely to be available — a portfolio lender can set its own policy without asking an investor. It also tends to raise the minimum, because the balances are larger and the administrative economics differ.
Floors in the tens of thousands are not unusual on jumbo recasts, and some private-bank relationships waive the fee while applying a substantial minimum. If you have a jumbo loan, ask both questions together: what is the minimum, and is the fee waived at relationship level.
Planning a lump sum around the floor
Work backwards from the payment you want. Run the balance, rate and remaining term through the calculator with different lump sums until the payment lands where you need it, then check whether that figure clears the servicer's floor.
Two outcomes are common. If the lump sum needed for the payment you want is *below* the floor, you have a choice: apply the floor amount and accept a larger payment reduction than you needed, or skip the recast and make an extra principal payment instead — which costs nothing and shortens the loan.
If the lump sum needed is *above* the floor, you are fine, and the only remaining question is whether the fee and the cash commitment are worth the relief.
What to do if you are just under
The obvious answer is to add to the lump sum until you clear the floor. That is right only if the extra money was already destined for the mortgage. Topping up by $6,000 to qualify for a recast that saves $40 a month is a poor trade unless the payment relief is the point.
The second option is to wait. A bonus, a tax refund or six months of saving can close the gap, and recasting later costs the same fee.
The option people forget: do the smaller payment as extra principal now. It does not lower your month, but it starts saving interest immediately and carries no fee, no approval and no minimum. If your servicer's floor excludes you from recasting entirely, this is the only route that still moves you forward.
How to confirm your own threshold
Ask in one written message, alongside the other two questions that matter: is a recast available on my loan, what is the minimum principal reduction, and what is the fee. Use a secure message rather than the phone so the answer is durable.
Then check the answer against your statement. If the servicer says 10% of the balance and your balance is $248,000, the floor is $24,800 — which is a materially different decision from the $5,000 you might have assumed. Getting that number wrong in either direction wastes either a request or an opportunity.
Frequently asked questions
The questions that come up most often.