TheAlgorithms/Python · error · Exception

value should be between 0 and 1

Error message

value should be between 0 and 1

What it means

Raised by hsv_to_rgb() in conversions/rgb_hsv_conversion.py when value < 0 or value > 1. Here 'value' is HSV brightness (V), expected as a fraction in [0, 1]; percentage inputs are the usual culprit. Raised as bare Exception.

Source

Thrown at conversions/rgb_hsv_conversion.py:49

    >>> hsv_to_rgb(240, 1, 1)
    [0, 0, 255]
    >>> hsv_to_rgb(300, 1, 1)
    [255, 0, 255]
    >>> hsv_to_rgb(180, 0.5, 0.5)
    [64, 128, 128]
    >>> hsv_to_rgb(234, 0.14, 0.88)
    [193, 196, 224]
    >>> hsv_to_rgb(330, 0.75, 0.5)
    [128, 32, 80]
    """
    if hue < 0 or hue > 360:
        raise Exception("hue should be between 0 and 360")

    if saturation < 0 or saturation > 1:
        raise Exception("saturation should be between 0 and 1")

    if value < 0 or value > 1:
        raise Exception("value should be between 0 and 1")

    chroma = value * saturation
    hue_section = hue / 60
    second_largest_component = chroma * (1 - abs(hue_section % 2 - 1))
    match_value = value - chroma

    if hue_section >= 0 and hue_section <= 1:
        red = round(255 * (chroma + match_value))
        green = round(255 * (second_largest_component + match_value))
        blue = round(255 * (match_value))
    elif hue_section > 1 and hue_section <= 2:
        red = round(255 * (second_largest_component + match_value))
        green = round(255 * (chroma + match_value))
        blue = round(255 * (match_value))
    elif hue_section > 2 and hue_section <= 3:
        red = round(255 * (match_value))
        green = round(255 * (chroma + match_value))
        blue = round(255 * (second_largest_component + match_value))

View on GitHub (pinned to f5988cc097)

Solutions

1. Convert 0..100 scales to fractions: value / 100.
2. Clamp: max(0.0, min(1.0, value)).
3. If your source is HSL, convert HSL->HSV first rather than passing lightness as value.

Example fix

# before
hsv_to_rgb(300, 1, 100)  # Exception: value should be between 0 and 1

# after
hsv_to_rgb(300, 1, 100 / 100)  # [255, 0, 255]

if not 0 <= value <= 1:
    value = max(0.0, min(1.0, value / 100 if value > 1 else value))
hsv_to_rgb(hue, saturation, value)

def valid_v_brightness(v: float) -> bool:
    return 0 <= v <= 1

try:
    hsv_to_rgb(h, s, v)
except Exception as e:  # bare Exception from the library
    if 'value should be' in str(e):
        hsv_to_rgb(h, s, v / 100)  # percentage input
    else:
        raise

When it happens

Trigger: Calling hsv_to_rgb(300, 1, 100) (percent), hsv_to_rgb(0, 0, -0.1), or feeding lightness/brightness from a 0..100 UI control unconverted.

Common situations: Brightness sliders in 0..100 range; confusing HSV 'value' with HSL 'lightness' or with 8-bit 0..255 scale; importing colors from formats that use percentages.

Related errors

• Expected int of the range 0..255
• hue should be between 0 and 360
• saturation should be between 0 and 1
• red should be between 0 and 255
• green should be between 0 and 255

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/1867ddcb73b57bd7. Report an issue: GitHub.