Cost-Plus Rate Calculator

01 The problem

Quoting a cost-plus rate in a meeting meant opening a spreadsheet, finding the right tab, and trusting the formula was still current. That was slower than the conversation. It pulled my attention off the person in front of me and onto a file. One stale cell or a fat-fingered margin and I quoted the wrong number out loud. I needed the rate in my hand, not three taps and a leap of faith away.

02 The system

A single-screen calculator that does the markup math as you type. You enter the base cost and the terms, and the marked-up rate updates live. It installs to a phone like an app and runs fully offline, so a rate is ready on the spot, with or without signal. No tabs to hunt through, no formula to second-guess.

03 How it holds up

It is one self-contained file with no dependencies. Nothing to load, nothing to update, nothing to break. Once it is on the phone it stays put, and it works the same on a plane or in a basement as it does on wifi. That is the whole point of a tool you reach for mid-conversation. I built it once and I have not had to touch it since.

04 The result

Now I quote a clean rate in seconds, anywhere, with or without signal. I stay in the conversation instead of digging through a file. The spreadsheet stays closed, and there is nothing to maintain. It is a small, sharp tool that does one job well.