Free tool

Payment Schedule Calculator

A milestone schedule agreed up front is the cheapest way to avoid an argument later. Set the contract, the number of milestones and your retainage rate and this produces the whole table — gross, retainage and net for each milestone, with a column that sums to the contract exactly rather than approximately.

Total net payments

$90,000.01

Contract amount: $100,000.00
Milestones: $3.00
Total gross: $100,000.00
Total retainage: $9,999.99

Milestone	Scheduled	Cumulative %	Gross payment	Retainage	Net payment
1	—	33.33	$33,333.33	$3,333.33	$30,000.00
2	—	66.67	$33,333.33	$3,333.33	$30,000.00
3	—	100.00	$33,333.34	$3,333.33	$30,000.01

The gross column always sums to the contract exactly. Where an even split leaves a fractional cent, the remainder lands on the final milestone rather than being rounded away.

How the calculation works

Gross payment: Contract × Milestone %; Allocated in cents so the column totals the contract.
Retainage: Gross payment × Retainage %
Net payment: Gross payment − Retainage
Cumulative %: Gross to date ÷ Contract
Total net: Total gross − Total retainage

Worked example

Contract amount: $100,000.00
Milestones: 3, split evenly
Milestone 1 gross: $33,333.33
Milestone 2 gross: $33,333.33
Milestone 3 gross: $33,333.34
Total gross: $100,000.00
Total retainage at 10%: $9,999.99
Total net: $90,000.01

The third milestone is a cent larger on purpose. A third of $100,000 is $33,333.33 recurring; round each milestone independently and the schedule totals $99,999.99, which is a conversation with the owner nobody wants. The remainder lands on the final milestone instead, so the column is exact.

How to use it

01Enter the contract amount and how many milestones the schedule has.
02Leave milestone percentages blank for an even split, or enter them comma separated — for example 10,30,40,20 for a front-loaded schedule.
03Set retainage to the rate in your contract. It is applied to each milestone as it is billed.
04Add project start and end dates to spread scheduled dates evenly across the job.
05Check that custom percentages total 100. They are used exactly as entered and never silently adjusted.

Common mistakes

Building a schedule that does not total the contract

Rounding each milestone independently leaves a schedule that adds up to a cent or two either side of the contract value. It looks trivial and it undermines confidence in every other number on the page.

Front-loading beyond what the work supports

Weighting early milestones improves cash flow and owners know it. A schedule of values that clearly overstates early progress invites scrutiny of every subsequent application.

Ignoring retainage when planning around milestones

The net column is what actually arrives. Planning against gross milestone values overstates available cash by exactly the retainage rate, every single time.

Percentages that do not total 100

A schedule totalling 95% quietly leaves 5% of the contract unbilled. This tool uses what you enter rather than rescaling it, because silently fixing the number would hide the mistake instead of surfacing it.

Questions

What is a construction payment schedule?

An agreed plan setting out when payments become due across a project, usually tied to milestones or to a percentage of completion, and forming the basis of each application for payment.

How should milestones be weighted?

In proportion to the work each represents. Owners and lenders compare the schedule against a schedule of values, so weightings that do not reflect real progress tend to be challenged.

Why is the last milestone a different amount?

Because an even split rarely divides into whole cents. Rather than rounding each milestone and leaving the total short, the remainder is placed on the final milestone so the column sums to the contract exactly.

Does retainage apply to every milestone?

Under most contracts, yes — it is withheld from each payment until released. Some contracts reduce or stop retainage after a completion threshold, so check the clause before forecasting.

Can I use uneven milestone percentages?

Yes. Enter them comma separated. They are used exactly as given, and the total is reported so you can see immediately whether it comes to 100.