SAD Risk Assessment Calculator

Introduction

Seasonal affective disorder, often shortened to SAD, describes a repeating pattern of depression that tends to appear during particular seasons, most commonly in late fall and winter when daylight becomes shorter. People who struggle with it often notice more than a brief dip in mood. They may feel slowed down, less interested in normal activities, unusually sleepy, hungrier for carbohydrate-heavy foods, or less able to get moving on dark mornings. When spring arrives and daylight lengthens, those symptoms often improve.

This calculator is an educational screening aid rather than a diagnostic tool. It combines your answers to five symptom questions with two light-related factors that can influence winter mood: your distance from the equator and how much time you usually spend outdoors. The result is meant to help you think in a structured way about seasonal patterns. It cannot confirm or rule out SAD, major depression, or any other mental health condition, but it can help you decide whether your winter pattern deserves closer attention or a professional conversation.

It is also useful to remember that seasonal mood changes exist on a spectrum. Some people experience a mild winter slump that does not significantly affect daily life, while others see a clear seasonal cycle that interferes with work, relationships, sleep, and motivation. A simple score cannot capture every detail of that experience, but it can make the major risk signals easier to see at a glance.

How to use this calculator

Start by answering the five questionnaire items as honestly as you can. The most useful answers are based on your usual pattern over the last one or two winters, not just on how you feel today. If one bad week has stood out recently, try not to let that single week dominate your choices. The goal is to reflect your typical seasonal pattern.

After the symptom questions, enter your approximate latitude and your average daily outdoor time during darker months. If you live in the southern hemisphere, you can enter a negative latitude, but the calculator uses the absolute value, meaning it mainly cares about how far you are from the equator rather than whether you are north or south. For outdoor time, think about a rough daily average across workdays and weekends.

1. Choose how often each seasonal symptom happens for you.
2. Enter latitude in degrees, from -90 to 90.
3. Enter your average outdoor minutes per day.
4. Select Calculate Risk to see your score, risk band, and short guidance message.

Use the result as a prompt for reflection. If the score looks higher than you expected, ask yourself whether daylight, sleep timing, exercise, and social routine change more in winter than you realized. If the score is low but you still feel distressed, trust the distress itself. Mental health decisions should never depend on a calculator alone.

Understanding Seasonal Affective Disorder

SAD is commonly linked to the way seasonal light affects the brain and body. As days shorten, many people get less bright light overall and less morning light in particular. That shift can influence circadian rhythms, energy, sleep timing, and mood regulation. For some people the result is a recognizable winter pattern of depression. Typical symptoms include feeling down, slowed, withdrawn, sleepy, and less motivated, along with changes in appetite or craving patterns.

At the same time, not every winter mood change is SAD. Stress, chronic medical issues, thyroid problems, iron deficiency, disrupted sleep, medication side effects, burnout, and nonseasonal depression can all produce symptoms that overlap with this condition. That is why the calculator is framed as a risk estimate rather than a diagnosis. It is designed to highlight a pattern, not to settle one.

How the questionnaire works

The questionnaire focuses on five practical signals that often show up in winter-pattern depression. Four questions ask how often you notice classic seasonal symptoms. The fifth asks whether you have ever previously been diagnosed with depression, because a history of depression can make seasonal relapse more plausible.

• Moods dropping in late fall or winter
• Craving carbohydrates or heavier foods during darker months
• Low energy when daylight becomes shorter
• Trouble waking on dark mornings
• A previous diagnosis of depression

For the first four items, the answer choices are Never, Rarely, Sometimes, and Often. Those responses are converted into scores from 0 to 3. The previous depression question is scored as 0 for No and 1 for Yes. The calculator then adds simple environmental adjustments for latitude and outdoor time. That structure is intentionally straightforward so that the result remains easy to understand.

Because memory can be imperfect, it helps to think through more than one winter when answering. If you had one unusually easy winter and one very difficult one, your score may sit somewhere in the middle. That does not mean the tool failed; it means your experience is variable and may need richer context than a brief online screen can provide.

Scoring model and formulas

The score comes from a basic additive model. Each questionnaire response becomes a number, those numbers are summed, and then two light-related adjustments are added. The first adjustment uses absolute latitude. The second adjustment checks whether your reported outdoor time is below 30 minutes per day.

• Mood drops in late fall: Never = 0, Rarely = 1, Sometimes = 2, Often = 3
• Carbohydrate cravings in winter: Never = 0, Rarely = 1, Sometimes = 2, Often = 3
• Low energy with shorter days: Never = 0, Rarely = 1, Sometimes = 2, Often = 3
• Trouble waking on dark mornings: Never = 0, Rarely = 1, Sometimes = 2, Often = 3
• Previous depression diagnosis: No = 0, Yes = 1

The additional adjustments match the calculator logic used on this page:

• Latitude adjustment, L: 0 points when absolute latitude is 45° or less, 1 point when absolute latitude is greater than 45° but not greater than 60°, and 2 points when absolute latitude is greater than 60°.
• Outdoor time adjustment, O: 0 points when average outdoor time is at least 30 minutes per day, and 1 point when it is less than 30 minutes.

The final risk score S is the sum of the five questionnaire item scores plus those two adjustments. The displayed symbolic form is:

In plain language, r₁ through r₅ stand for the five questionnaire scores, L is the latitude adjustment, and O is the outdoor-time adjustment. The maximum questionnaire subtotal is 13, and the two adjustments can add up to 3 more points, giving a theoretical maximum total score of 16.

This is not a clinical scoring instrument with diagnostic cutoffs. It is a teaching model. The benefit of such a model is transparency: you can see exactly why your result landed where it did, instead of receiving a mysterious score with no explanation.

Risk bands and interpreting your score

To make the output easier to read, the calculator translates the total into one of three broad bands. These bands follow the actual JavaScript scoring logic used by the calculator on this page.

• 0 to 3: Low risk - You report few seasonal symptoms and relatively limited environmental risk in this simplified model.
• 4 to 9: Moderate risk - You report several seasonal symptoms, a history of depression, less outdoor time, higher latitude, or some combination of these factors.
• 10 to 16: High risk - Your pattern strongly matches common winter-depression features within this educational scoring system.

The boundary between categories should not be treated as a hard medical line. A score of 9 and a score of 10 are very close, even though one falls in the moderate band and the other in the high band. Likewise, a low score does not guarantee that you are fine. If symptoms are intense, impairing, or frightening, the experience itself matters more than the category label.

Example calculation

Imagine a person who lives in a city at 52° latitude and spends about 20 minutes outdoors per winter day. They report that their mood often drops in late fall, they sometimes crave carbohydrates, they often feel low energy when days get shorter, they often struggle to wake on dark mornings, and they have previously been diagnosed with depression.

The questionnaire part of the score would be:

• Mood drop, Often = 3
• Carbohydrate cravings, Sometimes = 2
• Low energy, Often = 3
• Trouble waking, Often = 3
• Previous depression diagnosis, Yes = 1

That symptom subtotal is 12. The latitude adjustment adds 1 point because 52° is greater than 45° but not greater than 60°. The outdoor adjustment adds 1 point because 20 minutes is less than 30. The final score is therefore 12 + 1 + 1 = 14.

A score of 14 falls in the high risk band used by this page. That result does not establish a diagnosis, but it does suggest that the seasonal pattern is strong enough to justify closer monitoring and possibly a discussion with a clinician about winter mood changes, light exposure, sleep timing, and evidence-based treatment options.

Latitude, light exposure, and circadian rhythms

Latitude matters because it changes how dramatically daylight shifts across the year. Farther from the equator, winter days are shorter and the sun stays lower in the sky. That does not mean everyone at a high latitude will develop SAD, but it does mean the environmental backdrop is less forgiving. Morning light may be weaker, the useful daylight window can feel brief, and indoor schedules may crowd out outdoor exposure even more easily.

Outdoor time matters because even an overcast outdoor environment is usually much brighter than ordinary indoor lighting. Light is one of the main signals that helps anchor circadian rhythms, the internal timing system that influences alertness, sleep, appetite, and mood. If you rarely see natural daylight during winter, especially early in the day, your sleep-wake rhythm can drift and you may feel more sluggish or emotionally flat.

This calculator simplifies that reality into one practical threshold: less than 30 minutes outdoors adds one point. Real life is more nuanced than that. Morning light may be more helpful than late-evening light, cloud cover matters, and work schedules can shape exposure just as much as latitude does. Even so, the threshold is useful because it turns an abstract idea into a simple question: are you routinely getting outside at all during winter, or are many days passing with almost no natural light?

Comparison of risk bands and next steps

The table below summarizes how the three bands are meant to be read. The suggestions are educational and general, not personal medical advice.

Using your result responsibly

A calculator score is most helpful when it starts a thoughtful conversation rather than ending one. If your result is moderate or high, look for patterns that support or challenge it. Do symptoms show up mainly in darker months? Do weekends with more outdoor time feel different from workdays spent indoors? Does waking get much harder when mornings are dark? These are the kinds of observations a clinician can use far more effectively than a single number alone.

Many people find it helpful to pair a screening result with a simple winter self-check. You might keep a short weekly log of mood, sleep length, energy, appetite changes, exercise, and daylight exposure. Over time, that record can show whether the winter effect is mild and temporary or whether it is recurrent and disruptive enough to merit targeted treatment.

• Notice whether your low points repeat in the same season each year.
• Consider how sleep schedule and outdoor habits change as daylight shortens.
• Share the score and your observations with a qualified health professional.
• Plan small, realistic supports such as a morning walk, consistent wake time, or structured social activity during darker months.

Limitations, assumptions, and important disclaimers

This tool is intentionally simple and should be interpreted with caution. It is not a replacement for professional evaluation, and it leaves out many factors that matter in real mental health assessment.

• Not a diagnosis. The calculator does not diagnose SAD, major depressive disorder, bipolar disorder, anxiety disorders, or any other condition.
• Self-report limits. The result is only as accurate as your memory and self-observation. It is easy to underreport or overreport symptoms.
• Simplified model. The weights, latitude thresholds, and outdoor-time threshold are educational choices, not formal clinical cutoffs.
• Other causes exist. Low mood, heavy sleep, fatigue, and appetite changes can come from medical, psychological, social, or medication-related causes unrelated to seasons.
• Environment is more complex than latitude. Weather, work schedule, time spent near windows, shift work, and local routines also affect actual light exposure.
• Personal history matters. Age, current stress, substance use, trauma, medications, and other mental health diagnoses are not captured here.

Safety note: If you feel hopeless, cannot manage basic daily responsibilities, or have thoughts of harming yourself or others, seek urgent in-person help through emergency services, a crisis line, or a qualified local professional resource. An online calculator is never appropriate crisis care.

Used responsibly, this tool can still be valuable. It gives you a clear starting framework for thinking about seasonal symptoms, daylight exposure, and next steps. The most useful interpretation is usually not simply low, moderate, or high. It is the story behind the score: which symptoms are repeating, how much winter light you are getting, and whether that pattern deserves care.