Quote vs Estimate vs Proposal: What to Send a Customer

The first “quote” I ever sent was a text message. Four lines, a number at the bottom, sent from a parking lot. The customer read the number, I read the four lines, and three weeks later we were standing in their kitchen disagreeing about which of us had promised what. They had a fixed price in their head. I had a rough guess in mine. Neither of us had the text anymore, and I spent that evening retyping the whole thing into an invoice from memory.

I’m not a lawyer and I’m not an accountant. I built Proposals because that evening made me angry, and because every owner I talked to afterward had their own version of it.

Short answer: a quote is a fixed price for defined work, an estimate is an educated guess that can move, and a proposal is the scope and the price together, written so the customer can agree to it. An invoice is none of those — it’s the bill for work you’ve done. Send the one that matches how sure you are, and get it agreed in writing before you start.

What’s the difference between a quote, an estimate and a proposal?#

The difference is how committed you are to the number and how much of the job is written down next to it.

A quote says: this work, this price. If you quote $1,850 to replace a water heater and the job takes an extra hour, that’s your hour. Customers hear “quote” as a promise, and once they’ve accepted it, they’re usually right to.

An estimate says: based on what I can see today, it’ll land around here. It’s the right document when you can’t see the whole job yet — the subfloor under the tile, the wiring behind the panel. An estimate is honest about uncertainty, but only if you write the uncertainty down.

A proposal says: here’s what I’ll do, here’s what I won’t, here’s what it costs, and here’s where you agree. It carries the scope of work, the price, payment terms and a way for the customer to accept. It’s the only one of the three that’s built to be agreed to.

Is a quote legally binding?#

A quote usually becomes binding once the customer accepts it, because that’s how a contract forms: one party makes an offer, the other accepts it, and both give something up. Cornell’s Legal Information Institute lays out the elements in plain language in its Wex entry on contracts. The text message in my parking lot was an offer. The customer’s “sounds good” was an acceptance. I just didn’t have it in writing.

Labels matter less than you’d hope. If your “estimate” reads like a firm price — one number, no range, no conditions — a customer can reasonably treat it as one. The Federal Trade Commission tells homeowners to get written estimates that spell out the work, the materials, the completion date and the price, and to get every promise into the written contract. That’s the standard your customer is holding you to. In Florida, the Deceptive and Unfair Trade Practices Act, Fla. Stat. §501.204, prohibits unfair or deceptive practices in trade, and other states have their own versions. If a price is going to move, say so in writing before the customer agrees.

The honest answer is that none of this is legal advice and Proposals is not a contract-law tool. It gets the scope, the price and the customer’s acceptance onto one document and keeps that document from changing afterward. If a job carries liability terms — indemnity, warranties, anything a lawyer would charge to read — run the language past a lawyer before you reuse it.

When should I send a proposal instead of a quote?#

Send a proposal when the scope has more than one moving part, when there’s anything you specifically won’t do, or when the job runs longer than a day.

A quote works fine for a one-line job: pressure-wash the driveway, $225. A proposal earns its keep when the job has phases (demo, rough-in, finish), when there are exclusions (we’re not responsible for what’s behind the drywall), or when it repeats (monthly lawn service, quarterly HVAC maintenance). Those are the jobs where scope creeps, and scope creeps in the gap between what you meant and what you wrote. A proposal closes the gap by making you write it.

One of our beta users — a composite of a couple of people, so don’t go looking for him — ran a two-person HVAC shop and sent every job as a one-number quote. Change-outs went fine. Ductwork didn’t, because ductwork is where the customer adds “oh, and the back bedroom too.” He switched to a proposal with the back bedroom as its own line, and the argument moved from the end of the job to the start, where it’s cheaper.

What should a proposal include?#

A proposal needs the scope of work, the price, what’s excluded, when payment is due, how long the offer stands, and a way for the customer to agree.

Here’s the version I’d write on a kitchen table:

1. Who and where. Customer name, job address, your business details.
2. Scope of work. What you’ll do, in the order you’ll do it. Short sentences. If you’re phasing it, one block per phase.
3. Exclusions. What you won’t do. This line prevents more arguments than any other.
4. Price. Fixed, ranged, or per line item. If it’s per phase, show each phase’s number.
5. Payment terms. Deposit, progress payments, final — and when each is due.
6. Expiration. Materials prices move. Give the offer a shelf life.
7. Acceptance. Their name and the date, in writing.

That’s the whole document. You can write it in a word processor, and plenty of owners do. The trouble isn’t writing it once. It’s writing it 40 times a year, chasing the yes, and retyping the agreed lines into a separate invoice.

How does simpleWhirks Proposals handle this?#

Proposals exists so the document your customer agreed to is the same document you bill from. Here’s what it does today, and what it doesn’t yet.

Build it once. Start a proposal in the Quote Builder: your line items with descriptions, quantities and prices, priced as a fixed job or as time and materials. Your business name and details come from Hub, so you don’t type them again.

Send it. The customer gets an email with a link. They open it on their phone or computer — no account, no app to install — read it, type their name and tick the box to accept. Their name, the date and time, and where they accepted from are saved with the proposal. Every proposal carries an expiration date, 30 days unless you change the default in Settings, and an expired proposal can’t be accepted.

It stays the way you sent it. Once a proposal goes out, it can’t be edited, and the business details on it are frozen as of that send. If your business details change in Hub next month, the proposal still says what it said when the customer read it.

Turn it into an invoice. This is the part that fixed my parking-lot evening. From the accepted proposal, one click on Create Invoice copies its lines and prices into a new invoice — no retyping. Optional items aren’t carried over, so add any the customer asked for before you send it. The invoice opens in the same editor Books uses, laid out for a phone, so the edit you need to make from the truck is a thumb away.

Get paid and keep the record. Record a payment in full or in parts — cash, check, card or ACH — and write off what won’t be paid. Each invoice keeps its own history: when it was sent, when the customer opened it, every payment recorded. When a customer says they never got it, you can see the day they opened it.

Small jobs skip the proposal. For the $225 driveway, start a New Invoice directly — no proposal, same editor, same history. Not every job needs an agreement step, and we didn’t want to make you pretend it does.

What we don’t do yet, plainly: the Quote Builder is the template you can use today; the recurring, line-item and multi-phase templates are still marked coming soon in the app. Acceptance is a typed name, not a drawn signature. Proposals won’t draft legal terms for you, and there’s no change-order feature — if the scope changes mid-job, you send a new proposal for the added work. And Proposals invoices don’t flow into Books on their own yet; if you keep your books in Books, record the payment there too. I’d rather you hear that here than find out mid-job.

About the author. Travis Sutphin is the CTO and co-founder of simpleWhirks. He built Books and Proposals because the alternatives made him angry, and he writes about how they work: what’s stored where, what we chose not to build, and what doesn’t transfer. More from Travis.

Nothing here is legal advice. Contract and consumer-protection rules vary by state; talk to a lawyer about terms you plan to reuse.

Sources cited: Cornell Law School, Legal Information Institute, Wex: Contract · Federal Trade Commission, How To Avoid a Home Improvement Scam · Florida Statutes, §501.204, Florida Deceptive and Unfair Trade Practices Act