ActuarialOS
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Custom builds

Tell us the job.
We’ll build the tool.

The calculation you rebuild every quarter. The workbook that breaks whenever someone inserts a row. The report one person assembles by hand out of four files. Send us the brief and you get a written scope and a fixed price — usually within 3–5 business days.

Start a request →How it works

Review and quote are free · no obligation · most of what we build is actuarial, not all of it

What we build

Whatever shape the problem actually is.

Same engineering standard as the rest of ActuarialOS: inputs separated from logic, calculations you can trace and defend, and documentation of how it works. Personal or business, one-off or every month.

Excel workbooks & models

A calculator, a projection model, a reporting template. Formulas you can read, inputs separated from logic, and a sheet that tells you when something doesn’t tie.

Excel add-ins & automation

Custom worksheet functions, a task pane, or a macro that turns twenty minutes of clicking into one button. Runs on your machine, against your files.

Small desktop & web apps

When a spreadsheet has stopped being the right shape — several users, saved history, a real interface, exports that go out to someone else.

Data cleanup & report packs

The messy extract that gets hand-fixed every month, the report someone assembles out of four files. Made repeatable, and checkable.

How it works

From brief to fixed price in about a week.

No discovery-call gauntlet before anyone will name a number. Send the brief, get a scope and a price you can decide on.

  1. 10–20 minutes

    You send the brief

    Answer what you can below — four questions are required, the rest sharpen the quote. The page builds a formatted email; attach your samples, screenshots, and reference docs when it opens.

  2. Within 1 business day

    We confirm we have it

    A reply from a person, not an autoresponder — with any immediate questions if something we can’t scope without is missing.

  3. 3–5 business days

    Scope and fixed-price quote

    A written scope: what it does, what it deliberately doesn’t, what we’d need from you, and a fixed price with a delivery date. If the ask is still fuzzy you get a short list of follow-up questions — or a 20-minute call — in that same window. The review and the quote are free.

  4. See timelines

    Build, review, deliver

    You see it working partway through, not only at the end. Delivery includes a walkthrough, documentation of how it calculates, and a revision round.

Typical build timelines

From go-ahead to delivery. Your quote names an actual date.

Excel workbook or template
A calculator, model, or reporting template — locked inputs, readable formulas, built-in checks.
1–2 weeks
Complex workbook or Excel add-in
Multi-sheet models, custom worksheet functions, automation, or anything that reads a system export.
2–4 weeks
Small desktop or web app
A real interface, stored data, several users, exports and reporting.
4–8 weeks

Pricing is fixed-fee against the written scope, not hourly — you approve a number before anything gets built. If the brief isn’t complete enough to price honestly, you’ll get questions rather than a padded guess.

The brief

Answer what you can.

Four questions are required. Everything else is optional — but every one you answer is a question we don’t have to come back and ask, and a guess we don’t have to price around. It fills in an email; nothing here is submitted or stored.

Send pictures and files

A screenshot of the sheet you use today is worth three paragraphs describing it. So is a phone photo of a sketch on paper. Attach them to the email this page opens — samples, screenshots, the report format it has to match, the regulation or spec it has to follow, and a worked example of inputs with the answer you expect.

Don’t send live client data

Not in a first email. An anonymized extract, twenty made-up rows in the real layout, or a screenshot with names blanked out tells us everything we need. Once there’s a signed scope we’ll agree how real data moves — including builds where it never leaves your machine.

0 of 37 answered· 4 required, the rest sharpen the quote

About you and the ask

About you and the ask

So the quote goes to the right place, in the right language.

Where the scope and quote go.

It tells us which conventions and vocabulary to build to.

The job to be done

The job to be done

The most valuable section. Describe the work, not the software you imagine doing it.

Step by step, including the tedious and error-prone parts. If it isn’t done at all today, say what happens instead.

This is what the build has to earn back.

Re-keying, version drift, a formula nobody understands, only one person can run it, it’s wrong sometimes and you can’t tell when.

Decides how much of the tool is guardrails.

Inputs and data

Inputs and data

What the tool has to swallow, and how much of it.

e.g. a CSV export from our admin system, a vendor PDF, a monthly email, typed in by hand, pulled from a database.

Often the difference between a workbook and an application.

Is any of the data sensitive?
The rules and calculations

The rules and calculations

What has to be right. Rough is fine — we firm it up in scoping.

Describe them, or point us at the source — a regulation, a plan document, a textbook, a contract, the spreadsheet you already use.

An IRS notice, an ASOP, a published table, a standard, a vendor spec, a client agreement. Link it or attach it.

The single most useful thing you can send. It’s how we prove the tool is right, and it becomes the test we build against.

The ones you handle by hand today, or the ones that trip people up.

What comes out

What comes out

The thing you actually hand to someone.

Numbers on screen, a formatted table, charts, a PDF report, a file that feeds another system, an email someone forwards on.

What formats do you need?
Shape of the build

Shape of the build

Skip all of this if you’d rather we recommended something.

What will it run on?

An add-in that IT won’t sign is a tool you can’t use. Better to know now.

Does it need to connect to anything?
Show us

Show us

A screenshot beats three paragraphs. Attach these to the email the page opens.

What are you attaching?

Tick them here and the brief ends with a reminder to attach them.

A tool you already like, a layout you want copied, branding we should match, or a pet hate to steer well clear of.

Timing, budget, and what happens after

Timing, budget, and what happens after

What turns a good idea into a scoped project.

Not a commitment, and not a filter. It tells us whether to scope a lean version one or the whole thing.

The fastest way to a smaller number.

Will it need ongoing updates?

Send the brief

This builds a formatted email to hello@actuarialos.io and opens it wherever you read your mail — so you can attach your files and keep a copy of what you sent. Nothing is submitted from this page.

No mail app on this machine? Open it in or instead — or copy the brief and paste it into any email. All three land the same thing.

Preview the brief (5 lines)
CUSTOM TOOL REQUEST
via actuarialos.io/tools/custom

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0 of 37 questions answered.

Rather just describe it in your own words? hello@actuarialos.io works too — we’ll reply within 1 business day with whatever we still need.