Like all the other commenters have said you're not really asking for an "estimate". A fixed cost project does NOT have estimates. Estimate occur when you do tim

Like all the other commenters have said you're not really asking for an "estimate". A fixed cost project does NOT have estimates. Estimate occur when you do time and materials i.e. you get charged per hour and it can always get extended. There's competition and you roughly know where the bid will land (assuming you're already experienced) and likely talking to each other. Instead of giving a real estimate anyone knows you pad any real estimate 3x and then drag it out if you're under time. I once tried to give a real estimate, finish it under time and got told for it because then we can't bill the client (time based). Again, no it's not an estimate. It's called I have $x and y time and want to do <z>, how many corners can I cut whilst the client won't notice?