The bulk of the film take places over a period of five days, starting with Giselle meeting Edward and finishing with Edward and Nancy's wedding.
This is borne out by both the screenplay and official novelisation (and what we see on screen).
Day 1 - Giselle meets Edward in the forest. They agree to marry the next day.
"Giselle! We shall be married in the morning!" the prince announced.
Giselle was so excited when she pulled up to the castle the next morning that she opened her carriage door rather quickly.
Day 2 - Giselle comes to the castle for her wedding and is pushed by a hag into a magical portal, leaving Andalasia (morning) arriving New York (evening). Robert rescues her and she spends the night in his apartment.
Robert waits on the phone. Despite his better judgement, he just can't bring himself to send her back out into the night.
DISPATCHER (O.S.) (cont'd): “Hello, sir. Destination please?”
But Robert doesn't answer, his eyes still on Giselle as he quietly
clicks off the phone.
INT. ROBERT'S LIVING ROOM - MORNING
Giselle wakes with a demure sleepy stretch on the couch. Slowly
batting her eyes awake, she looks around the room to realize... The
home of her newfound friends is an untidy mess (the sloth of busy
single parent)! Dirty clothes are strewn about, magazines litter the
floor and the sink is full of dirty dishes.
Day 3 - Giselle makes a dress, sings in Central Park (and sends Ball tickets to Nancy with a verbal confirmation that the ball is tomorrow) and has a meal at an Italian restaurant.
"Yeah, usually you send those e-mail cards with the digital flowers. These are exquisite. Where do you find live doves in New York City?" Nancy cried. "And these?" she added, holding up a pair of golden tickets. "We're going to a ball?"
Robert smiled. Well, that was easy, he thought. "So, tomorrow night, then?"
Day 4 - Edward arrives at the apartment. Giselle and Edward have a date. Giselle buys clothes and they all meet at the ball later.
ROBERT: Okay. ' Night.
Robert turns and walks back to his room, Giselle helplessly taking
in the view from the other side, flustered as she swallows hard.
DISSOLVE TO: EXT. NEW YORK CITY - MORNING
A burning sun backlights the skyline like a halo.
INT. ROBERT'S APARTMENT BUILDING HALLWAY - MORNING
Bright light floods the hallway as an exhausted Edward drags
himself down the hall, ringing the last bell on the last door!
Day 5 - The wedding scene at the end takes place the following day
The very next day, at the palace in the magical world of Andalasia, Prince Edward and Nancy were married. It was a royal ceremony, and everyone remarked that Nancy made a beautiful princess.
The very last scenes (Giselle taking over Nancy's studio, Pip and Nathaniel touring on their bestsellers) take place at an unidentified point in the future.