There is no way to get a guess for a project . Many things come into play and a ID is great but you still might need an engineer if removing walls and what exactly do oyu want form this ID. A plan , all the choices made by them ? You have to be very exact about what you expect form an ID then you go shopping for one. Not all IDs are kitchen designers so be aware of that too.

Well, I’m no pro. As Patricia says, it varies widely. Just a reference for you. I contacted a couple designers to give me quotes for space planning and furnishings for my new office area. About 170 sq ft room. One had a $3500 retainer and estimated about $8000 plus furnishings. As well, she worked out a shopping deal but I forget how much she charged: she’d go with me and we’d look at furniture and accessories, etc. I want to say $75-100 an hour but I’m not sure. I paid her $350 for a few drawings of room options. I did not use a designer on that room. When I looked for designers for my kitchen, which I thought would be a big job, I was told by two people their fees add about 25-30% of the total renovations cost. So: $150k kitchen renovations plus $37-40k in designer fees. I ended up moving ☺️. But the way, this was in a high cost of living area, coastal California, pre-Covid.

No one can hazard a guess. Interior designers structure their fees based on experience, and this could be years or decades Also their markets, their costs of doing business . You could be near the center of Boston, or in the woods of Springfield. Personally, I know none who work on a flat "whole project " fee for anything residential.

You will ask why. I will answer in one word.

Emotion.

Emotion is the word that defines residential work. It is why architects generally specialize in EITHER residential or commercial, and the same holds true for interior designers. Homes are simply more personal - the same owner who'd be speedily decisive/ fine with a pleasing, functional result in a corporate setting could spin and twist him or herself into knots regarding their own home!

I can only tell you what you want.

You want someone to work in tandem with your architect/ contractor/subs. The informed go between/ the guru between you and them. You want a built in? A mud cubbie area? He/she designs it - contractor executes.

As it applies to your kitchen? A good interior designer generally has a pro KD on speed dial. I often "design" a kitchen/bath layout, spec all finishes, select appliances, lighting, tops, et al with a client, but no possible way am I writing a cabinet order- hours and hours FRAUGHT WITH MISTAKE POTENTIAL!

You want the interior to flow. That means as it applies to all the elements in whatever your end desired style /flavor shall be. From trims, to flooring to you name it. All the permanent aspects and their colors, materials, finishes.

You will need some furnishings.? Rugs, seating, tables, lighting , accessories.....the elements that make your home, yours. Some you undoubtedly own and want to keep. some will be new. What's your budget? How decisive are you? Do you need to see two options? Or will you need to see six? ( Not recommended btw ).

Which is why you need a very clear idea of what you want or expect from any designer, and must understand that the more attention and service ? Hence follows the "price".

You aren't just paying for a designers time. You are paying for the art, the science, the skill, the experience. As I say to clients?

"This all sounds abstract, does it not? It is in fact abstract, UNTIL.....you arrive at a destination that thrills you. The result that you never imagined could be so lovely, functional, comfortable and y.o.u. You pay for that reality; that is the point and only purpose, any designer, anywhere"

Bottom line? Find the "one" .

Talk to friends who've done work. Talk to a few designers and clarify your expectations with regard to scope of work and your budget. Get a clear contract, make sure you fully understand it, before you sign it.

Is there another way? No.

Working with any designer is an ongoing relationship. It's a dialogue , ideas, and more. It is mutual trust as well. You have to find that fit.

Thanks for the responses. I am in a suburb right outside of Boston. I did receive one design estimate and it was about 25% of project cost. All your feedback is helpful!