Underbid a Job? What to Do in the First 48 Hours

You underbid a job. The number is out, the customer said yes, and the arithmetic no longer works. Here is the short version: stop committing money, price the work that is left, and decide based on that number alone. What you have already spent is gone and cannot be recovered by finishing. Then raise it in writing, immediately, because the single largest factor in whether you get paid is not how reasonable your request is. It is whether you ask before or after the work happens.

The first question is not how much you lost

It is whether the contract is signed and whether a deposit has changed hands. Everything downstream branches from that, and most advice online skips it entirely.

If nothing is signed, your quote is an offer, and an offer can be corrected until it is accepted. A contractor in a November 2026 r/Contractor thread had bid a remodel at 22,000 dollars eight months earlier, went back to remeasure, and found the real number was closer to 38,000. He had not signed. The most upvoted practical reply was blunt about his three options: tell the truth, invent a reason, or withdraw. A contractor who identified himself as having been in the same position more than once gave the response worth remembering:

"The cleanest path is transparency. Call the client, explain that during your remeasure you realized the scope is significantly larger than what was originally captured. Own the mistake and present the corrected number with a calm, professional explanation. Some clients will understand, and some won't. But I've never regretted being upfront. The jobs where I tried to 'honor' a losing number ended up being the ones that cost me the most. Both financially and mentally."

If it is signed, you have a contract, and the price in it is the price. You are no longer correcting a quote. You are negotiating a change, and that requires a mechanism.

Step one: stop committing money for 48 hours

Before you tell anyone anything, stop spending. Cancel the material order that has not shipped. Do not schedule the sub for next week. Do not put the fixtures on your card.

This is about leverage, not the money you save. Every dollar you commit before the conversation is a dollar you have already volunteered. A customer who learns on Tuesday that you need another 9,000 dollars is deciding whether to fund the rest of a job. A customer who learns on Friday, after you bought everything, is being asked to reimburse a decision you made alone.

Keep working during those 48 hours. Pausing purchasing is prudent. Pausing the schedule without explanation is how a pricing dispute becomes a breach claim.

Step two: work out the only number that matters

Most contractors compute the wrong figure. They total the loss on the whole job, feel sick, and make an emotional decision. The total loss is a historical fact and it does not change based on what you do next.

The number you need is cost to complete. Price the scope that remains, at real cost, today. Then compare it to the money you have not yet been paid.

In that example, finishing costs 5,000 dollars more than it brings in, and that is true regardless of what happened before today. If the marginal number is positive, finish. You are still recovering something toward overhead, and finishing preserves the relationship, the referral and your licence. If it is negative, you have a real decision, and doing nothing is the most expensive option on the table.

The trap is that most contractors cannot compute cost to complete, because they do not know their actual costs to date. Projul's 2026 breakdown of margins by trade calls this margin fade: the gap between the margin you bid and the margin you realise. Their worked example is worth sitting with. An 85,000 dollar kitchen remodel with 64,300 dollars of direct costs shows a healthy 24.4 percent gross margin. Apply a 30 percent overhead burden rate and net profit is 1,410 dollars, a 1.7 percent net margin, on a job that looked comfortable at the gross level.

Step three: sort the overage into two buckets

This is the step that decides whether your request gets paid, and almost no published guide separates them.

Bucket one: concealed conditions. Things no reasonable pre-start inspection would have revealed. A second concrete slab poured on top of the first, reinforced with wire caging and steel posts. Knob-and-tube behind the drywall. Rot under the shingles. These sit outside your original scope, and customers routinely pay for them.

Bucket two: estimating misses. Arithmetic errors, a forgotten line item, labour hours you lowballed, a markup formula that did not carry through, or a price you held for eight months while your costs moved. These are yours.

Customers can tell the difference, and they respond to the two buckets completely differently. The owner's representative whose comment drew 446 upvotes on the r/Homebuilding walk-off thread put it from the customer's side with uncomfortable clarity:

"Absorbing estimating misses is exactly what a fixed-price GC gets paid their margin for. You can be sympathetic and still hold the line."

That is the deal you signed. Separate the buckets before you present anything. Ask for bucket one with specifics, photographs and dates. Decide consciously about bucket two, and expect to carry most of it. Contractors who bundle both into one ask are the reason so many operators believe change orders never get approved.

Step four: the timing rule that decides everything

Here is the finding none of the pages currently ranking for this topic mention. Two threads, same subreddit, same problem, opposite results.

In the first, a homeowner posted that their contractor had bid 5,000 dollars for brick stairs and a landing, estimated a few days, and was now in week three because the previous owner had poured a patio on top of another patio. The post drew over 500 upvotes and 450 comments, and the homeowner's question was how to fairly compensate the contractor. The top-voted reply told them to simply ask him what he would have charged had he known. Another commenter said the contractor was wrong to absorb it silently and should have raised a change order for the unforeseen condition. A second homeowner appeared in an unrelated thread asking the same thing.

In the second thread, a contractor wrote that he had vastly underbid, had effectively paid the customer to do the job, and asked whether there was any way to recoup it. He had already told them it cost more. The responses were unanimous and kind and useless: chalk it up as tuition, stand behind your contract, do a post-mortem. One reply reduced it to a sentence:

"Submit a change order. But if it's after the fact, you have to hope for the goodwill to pay it. If they don't, I'm sorry."

Same industry, same mistake, and the variable that separated a customer volunteering money from a customer owing nothing was not the size of the overage or the quality of the work. It was whether the ask arrived before or after the work was performed. A change order raised at day three is a business document. The identical request at day thirty is a favour, and you are asking for it at the exact moment your leverage reaches zero.

Our guide to change orders covers the mechanics of pricing and collecting them. The one rule that matters here is that the paperwork has to precede the work.

What to say, specifically

Call. Do not email, and do not text. Then keep it to four parts:

1. State the finding, not the feeling. "When I opened up the landing I found a second slab under the first, reinforced with wire and steel posts."
2. Quantify it. "That is roughly eleven extra hours of demo plus disposal, which comes to 1,850 dollars."
3. Separate what you are absorbing. "I also underestimated the mortar quantity. That one is on me and I am covering it."
4. Ask for a decision, not for sympathy. "I have written it up as a change order. Can we get it signed before I carry on tomorrow morning?"

Point three is what makes the other three credible. A contractor who visibly eats his own mistake while asking to be paid for the customer's surprise is making an argument the customer can accept without feeling handled. A contractor asking for the whole number is asking to be bailed out.

Never invent a reason. "Tariffs" and "material prices went up" were both proposed in that r/Contractor thread. Both invite negotiation on a premise that collapses the moment the customer looks it up.

What the loss actually costs you

Contractors consistently underrate a bad job because they compare it to their revenue rather than to their profit. Use this instead:

Revenue needed to recover a loss = loss divided by net margin

At an 8 percent net margin, a 5,000 dollar loss requires 62,500 dollars of additional revenue to return to even. At 12 percent it still requires about 41,700 dollars. At the 1.7 percent net margin in Projul's kitchen example, it needs roughly 294,000 dollars of work to absorb.

That multiplier is the argument for having the awkward conversation. Ten minutes of discomfort today is worth two months of production. It is also why "I will make it up on the next one" is not a plan. The next job does not cancel this one, it dilutes it.

What not to do, with a real example

Do not walk off. In January 2026, an r/Homebuilding poster described a fixed-price 850,000 dollar build where the GC suspended work at roughly 95 percent complete, with only electrical trim and sprinkler work outstanding, and demanded 56,000 dollars in retroactive, unsigned change orders. All contract draws were current and the owner had voluntarily advanced an extra 30,000 dollars.

The advice the owner received was to send a formal notice of default with a cure period, file a licensing board complaint, hire a construction attorney and finish with the subs directly in exchange for lien waivers. Another commenter described an almost identical situation on their own build that took 27 months to settle.

Read that from the builder's side. He had a real problem, a partially sympathetic customer, and a legitimate claim buried somewhere in his numbers. By choosing the wrong mechanism and the wrong moment, he turned it into a licensing complaint, a lawsuit, unpaid subs, and a job he still does not get paid for. Suspending work while the customer is current is a breach in most contracts, and it destroys whatever goodwill argument you had.

Two more things not to do: do not quietly cut corners to claw the money back, which is how an estimating problem becomes a warranty problem, and do not reach for bankruptcy first. Markup and Profit, replying to a contractor who had underbid a house by 14,000 dollars, pushed back hard on that instinct and offered the practical alternative. Show the owner the specific supplier and subcontractor bills you cannot cover and ask them to pay those parties directly, which settles the debts and keeps liens off their home at the same time. Talk to an attorney before signing or paying anything.

How to tell you are underbidding before the job ends

Three leading indicators, in order of how early they fire.

Your win rate is too high. If you are closing most of what you quote on cold, competitive work, that is a pricing signal rather than proof you are good at selling. One commenter's reply to the 22,000 dollar remodel post landed harder than any spreadsheet: "You're booked out 8 months because you can't bid." A full calendar is the most convincing disguise an underpricing problem ever wears. If this is where you are, how to stop competing on price is the more useful problem to work on than estimating accuracy.

Bid margin and invoice margin do not match. Compare estimated to actual on your last ten jobs, line by line. Projul names underestimated labour hours as the single largest cause of margin fade, and puts rework and callbacks at 5 to 12 percent of total project costs, a category most contractors never budget.

You are busy but not accumulating cash. The terminal symptom, and by the time you notice it you have usually run the pattern across many jobs. We covered the diagnosis in why you are busy but not making money.

The fix on all three is the same and it is unglamorous: track actual hours and costs against the estimate while the job is live. Contractors who only reconcile at final invoice are running an annual feedback loop on a problem that repeats weekly.

Recovering margin on a job you are stuck with

Sometimes the answer really is to finish at a loss. You can still limit the damage.

• Hold the scope line precisely. For the price you bid, you do what was written down and nothing else. Every additional request goes on a priced change order before the tools come out. This is where the money actually is.
• Stop giving away the small stuff. The extra outlet, the hauled-away debris, the second trip. On a job already underwater these are not goodwill, they are the difference between losing four thousand and losing six.
• Watch customer-supplied materials. One contractor offered to deduct owner-purchased items from his contract, and the owner bought high-end everything, leaving so little contract value that he did the entire month-long remodel alone and out of pocket. We covered this trap in customer-supplied materials.
• Get faster, not cheaper. Sequence properly, avoid return trips, keep the crew on one site. Labour overrun is the largest single cause of the gap.
• Bill on schedule and collect immediately. A loss you have been paid for is a loss. One you have not been paid for is far worse. If collection becomes the problem, what to do when a customer will not pay covers the sequence.

The 30-minute post-mortem

Do this within a week, while you still remember, and write it where you will see it during the next estimate.

1. What was the bid number, and what was the actual number?
2. Which line items missed, and by how much each?
3. Was it scope you did not see, quantity you got wrong, hours you underestimated, or markup that did not carry?
4. What would you have needed to know, and when, to catch it?
5. What one change to your estimating process would have caught it?

Then change the template, not just your intentions. The contractors who improve are the ones whose next bid physically contains the missed line item. Our guide to pricing a job covers the burdened labour and overhead allocation most post-mortems land on.

The short version

If it is not signed, re-quote it today and be specific about why. If it is signed, price the cost to complete, split the overage into concealed conditions and your own misses, ask for the first in writing before the work happens, and absorb the second. Do not walk off, invent a reason, or quietly cut corners.

Then fix the loop that produced it. One underbid job is a bad week. An estimating process that cannot tell you a job is underwater until the final invoice will keep producing them, at a net margin thin enough that it only takes a few.