Wash, peel, and pit the peaches. Finely chop or crush them using a potato masher. Measure exactly 4 cups of crushed peaches into a large bowl.
Add sugar to the peaches and stir well. Let sit for 10 minutes, stirring occasionally.
In a small saucepan, combine powdered pectin and water.
Bring to a rolling boil over medium heat, stirring constantly. Boil for 1 minute.
Remove from heat and immediately pour the hot pectin mixture into the peach mixture.
Stir continuously for 3–4 minutes until sugar is fully dissolved.
Pour jam into clean freezer-safe jars, leaving ½ inch headspace.
Let jars sit at room temperature for 24 hours to set.
Seal with lids and freeze for up to 1 year. Refrigerate after thawing and use within 3 weeks.
