Labor-Cost Roll-up from Timesheets: See Where the Effort Money Actually Went

The problem this kills

You can usually tell how many hours went into a project. What you almost never see clearly is how much money those hours cost — by project, by phase, by task. Hours are not dollars. A senior architect's hour and a junior coordinator's hour land in the same timesheet column, but they cost wildly different amounts, and that difference is exactly where margin is won or lost.

So someone in finance or the PMO ends up rebuilding it by hand: pull the approved hours, paste in a rate per person, write a VLOOKUP, and pray nobody changed their rate mid-project. The spreadsheet silently fills missing rates with a zero or last week's number. Rate changes get applied retroactively to hours that were logged at the old rate. A duplicated time export double-counts a whole week. And by the time the labor cost reaches the budget or margin report, nobody's quite sure it's right — but the deadline's here, so it ships anyway.

The result is project P&Ls and margin numbers built on a brittle, unauditable calculation that one person understands and nobody trusts. That's a problem worth killing.

What you'll build

A simple internal web app for your PMs and finance partners. You import your approved time entries (person, project, phase, task, hours, date) and your person-to-cost-rate table, and the tool does the one job a spreadsheet keeps getting wrong: it multiplies each approved hour by the correct cost rate for the date that hour was worked, then rolls the resulting labor cost up by project, phase, and task.

It handles the two things that quietly break every hand-built version. Rate changes over time: if someone's cost rate changed on a date, hours before that date use the old rate and hours after use the new one — no retroactive smearing. Missing rates: if an entry has no rate that covers its date, the tool flags it loudly and refuses to guess — no silent zeros, no "close enough." A finance or PM owner reviews the computed labor cost and the list of rate gaps, resolves or accepts them, and approves before the number is allowed to feed a budget or margin report. Then you export a clean roll-up CSV in the exact columns your budget tool expects.

What's inside the Implementation Plan

The downloadable plan is a step-by-step file you paste into an AI coding agent. It opens by interviewing you about your business — how your time gets approved and where it lives, the exact shape and column names of your time export, how your projects break into phases and tasks, how you identify people, how cost rates are set and how often they change, and the messy exceptions (contractors, overtime, blended rates, people who left). It reflects a short tailored spec back to you and gets your thumbs-up before it builds anything, so the roll-up matches how your projects and rates actually work — not a generic template.

From there it walks the agent through the data model, the time-and-rate import with duplicate guards, the date-aware rate matching, the roll-up engine by project/phase/task, the missing-rate flagging, the owner approval gate, and the CSV export. Every step ends with a ready-to-copy prompt. There's a full "No API yet?" path that uses Google Sheet / CSV imports as the data source and produces a clean CSV export — so you can build and run the whole thing this afternoon, no integration to your PSA, ERP, or timesheet system required.

The governance it includes (this is the point)

Cost rates are sensitive — they reveal what people are paid — and the labor cost feeds money decisions, so the controls aren't optional. The plan builds in login so only your team can use it, row-level security so you only ever see your own organization's projects and rates, access-restricted cost rates so only authorized owners can view or edit the rate table, a complete audit trail of who imported what, who edited a rate, and who approved which roll-up, a hard human-approval gate so no labor cost feeds a budget or margin report until the owner signs off on the numbers and the rate gaps, and duplicate guards keyed on the time-entry id so the same hours can't be counted twice on re-import.

Who it's for

Project managers, finance partners, and services/agency leaders — anyone who owns a project P&L, a utilization-and-margin report, or a client budget and needs labor cost they can actually trust, broken down to the task. If you can describe how your time gets approved and how your cost rates are set, you can build this.

You've got this — start with the plan, paste the first prompt, and answer the interview. You'll have your first trustworthy labor-cost roll-up on screen before the afternoon's out.