Money is frozen time. Convert any price into how many hours (and minutes) of your actual working life it costs — after tax, before snacks. That latte is cheaper once you've seen it in minutes.
Take-home pay means every pound has already been taxed, so a £10 thing bought from post-tax wages really costs more than £10 of your gross salary. This tool uses the hourly number you type as the true “life-to-pound” exchange rate and does the division. Nothing is stored.