InvoiceTools

Project invoice calculator

A project invoice bills a share of a fixed price rather than hours. On a $24,000 project at 40% complete with 5% retainage held back, this invoice is $9,120 before tax, with $480 retained until the job closes.

A share of a fixed price, with change orders and retainage.

Built for work priced as a whole and billed in stages: a percentage of the contract, plus any change orders agreed since, less the retainage the client holds until completion.

Retainage is the line that catches people out. It is not a discount and it is not lost, but it is money you do not have yet, and it belongs on the invoice rather than being discovered when the payment arrives short.

Percentage complete, agreed before it is billed

Billing a percentage works only when both sides agree what percentage is done. On larger jobs that is what a schedule of values is for: the contract broken into line items with a value each, so progress is a fact rather than an opinion.

On smaller work, agreeing the stages in the quote does the same job. What does not work is deciding the percentage yourself at invoice time.

Retainage is not a discount

Retainage, or retention, is a percentage the client holds back until the job closes and any defects are made good. Five to ten percent is typical on construction work. It is still yours; you just do not have it yet.

Show it as its own line on every invoice. A client who has watched it accumulate pays it at completion. One who never saw it mentioned treats your final invoice as a surprise.

Change orders in writing

A change order agreed verbally on site is not a change order, it is something you will be arguing about in two months. Put the scope change and the price in writing before the work happens. The quote generator produces one in a couple of minutes and it becomes part of the contract.

Related calculators

Questions people ask

How do I invoice a fixed-price project?

Bill the percentage of the contract that is complete, add any agreed change orders and reimbursable expenses, subtract retainage if the contract has it, apply tax, then subtract what you have already invoiced.

What is retainage?

A percentage the client holds back on each payment until the job is finished and any defects made good, commonly five or ten percent on construction work. It is released at completion, not written off.

Should retainage show on the invoice?

Yes, as its own line. A client who has seen it held on every invoice pays it at completion without argument. One who never saw it mentioned treats the final bill as a surprise.

How do I decide the percentage complete?

Agree it in advance. On larger jobs a schedule of values breaks the contract into items with a value each so progress is measurable. On small jobs, agree the stages in the quote.

Do change orders get taxed the same way?

Usually at the same rate as the contract work, but the treatment of labor varies by state. Check your own rules rather than assuming.

How do I turn this into an invoice?

The button under the result carries the contract percentage, change orders, expenses and the retainage line into the invoice generator with tax already set.

Send it yourself, or send it and watch it

Everything here is free with no account. Send a document as a link instead and you see when it was opened, which line they questioned, and who signed it, so chasing becomes a decision rather than a guess.

The first four documents you send as a tracked link are free with an account. Everything else on InvoiceTools.com stays free and needs no account.

Terms used on this page

Plain-English definitions, each with an example.