Short answer
Yes, you can read saju without a birth time: your birthday type comes from the date alone, along with three of the four pillars, and the hour only adds the fourth pillar unless you were born close to midnight.
What you get from the date alone
The year, month and day pillars, so six of the eight characters. That includes your birthday type (the day stem), your day branch and the season you were born into. Many Koreans use saju exactly like this, because plenty of people do not know their birth hour.
What the hour adds
The hour pillar, traditionally linked to later life, children and private ambitions, plus two more characters for the element count. It refines the chart but rarely changes the headline.
When the hour really matters
Two cases. If you were born between 11 pm and midnight, many Korean schools count the next day, which changes your birthday type. And if you were born on the day a solar term begins, your month pillar depends on the exact time. The free check tells you if either applies to you.
FAQ
Is my birthday type wrong without a birth time?
Almost never. It only changes if you were born between 11 pm and midnight, depending on the school a reader follows.
How do I find my birth time?
Birth certificates in some countries list it; otherwise a parent's memory or hospital records can help. If it stays unknown, the three-pillar reading is still meaningful.
Does birth place matter?
Your time zone matters for the exact moment of the solar terms. We use your browser's time zone by default, or the birthplace you choose.