Built for people who live in spreadsheets
Calculate My Hours solves a specific, frustrating problem: you have a spreadsheet full of start and end timestamps, and you need to know how many hours fall in between — broken down by total, business, weekend, and weekday. No formulas. No NETWORKDAYS headaches. Just upload, configure, and download.
How it works
Upload a spreadsheet (.xlsx, .xls, .ods, or .csv) with at least one column of start timestamps and one of end timestamps, with a header row at the top. The tool reads your file, lets you map which columns to use, and computes each selected metric row by row — calculating exact minute-level overlap with the relevant time windows.
Results are appended as new columns to your original data and returned as a downloadable .xlsx file. Your existing data is untouched; only the new columns are added.
You can select any combination of the four metrics, configure which days count as the weekend (Friday, Saturday, and/or Sunday), and set the daily start and end time for business hours calculations.
Your data stays on your computer
Everything runs locally in your browser using the SheetJS library. When you upload a file, it is read directly into memory on your device — it is never transmitted to a server, never stored in a database, and never leaves your machine. Closing the tab clears everything.
Why we built it
Spreadsheet formulas for time math — NETWORKDAYS, MOD, custom VBA — are brittle, hard to audit, and require rebuilding from scratch for every new file. We wanted a reusable tool you could hand to anyone on a team: upload your file, pick your columns, get your answer. No Excel expertise required.
The tool is free, supported by advertising, and will stay that way.