b2KIT

Clock Angle Calculator

Calculate the angle between clock hands at any time. Animated clock face shows acute and reflex angles with degree/radian values.

Tested tool guide Tested browser tools Checked August 16, 2026

What Clock Angle Calculator does, with a checked example

Every clock face is a 360-degree protractor in disguise: the hour hand sweeps 30 degrees per hour, the minute hand 6 per minute, so the angle between them is subtraction plus one correction. Enter any time and this tool rotates both hands on an animated dial, then shows the two angles between them - the smaller arc and its reflex complement - in degrees and radians. The part most people get wrong is the hour hand, which never sits still: by 3:30 it has drifted 15 degrees past the 3, leaving 75 degrees between the hands, not the 90 the numerals suggest.

Worked example

A concrete input and expected output from the current implementation.

Input

3:30

Expected output

75 degrees (5π/12 radians) for the smaller arc, 285 degrees (19π/12 radians) for the reflex arc, both drawn on the dial.

At 3:30 the minute hand points at 6 (180 degrees), while the hour hand has moved halfway from the 3 toward the 4, to 105 degrees (90 plus 15 degrees of drift). The difference is 75 degrees, and the reflex angle is 360 minus 75, or 285 degrees.

How the result is produced

1

The formula

On a 12-hour dial the hour hand advances 30 degrees per hour (360/12) plus 0.5 degrees per minute, and the minute hand 6 degrees per minute (360/60). For H hours and M minutes the raw gap is 30H + 0.5M - 6M, or 30H - 5.5M degrees. The answer shown is that value folded into the smaller arc; the reflex angle is its complement to 360.

2

The animated dial

The dial draws the hands at their true positions rather than at the hour markers, so at half-past times the hour hand visibly sits between numerals. Both arcs between the hands are highlighted, and their degree and radian labels update as the time changes, so you can watch the smaller angle shrink and grow across a full hour.

Good uses

  • Verifying the answer to the standard geometry question 'what is the angle between the clock hands at time X' from homework, worksheets, or puzzle books.
  • Tutoring or teaching the unit circle: the dial shows why the hour hand drifts continuously, which is the step that produces most wrong answers.
  • Getting the reflex angle or radian measure for drawing code, such as positioning hands in an SVG clock face or generating test data for a timepiece widget.

Limits and checks

  • 24-hour input: 14:30 is 2:30 on a 12-hour dial. Confirm the tool converts before trusting it; if it treats 14 as an hour, the hour hand lands a full half-turn off.
  • The smaller angle is not always acute: at 5:00 it is 150 degrees (obtuse), and at 6:00 the two arcs are equal at 180 degrees, so neither label is strictly accurate.
  • Seconds change the answer by about 0.09 degrees per second, since the gap grows 5.5 degrees per minute. A time rounded to the minute is fine, but 3:30:30 differs from 3:30:00 by roughly 2.75 degrees.

Common questions

Why is the angle at 3:30 not 90 degrees?

Because the hour hand keeps moving. In the 30 minutes after 3:00 it advances 15 degrees (0.5 per minute) to sit halfway between the 3 and the 4, at 105 degrees on the dial, while the minute hand is at 180. The gap is 75 degrees. The hands form a right angle 44 times a day, but never at 3:30.

How often do the hands line up on top of each other?

Eleven times per 12 hours, not twelve: the minute hand must close a 5.5-degree-per-minute relative gap, so each meeting comes 360/5.5, about 65 minutes and 27 seconds after the last. They coincide at 12:00, then roughly 1:05:27, 2:10:55, and 3:16:22, before repeating at 12:00.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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