What Is a Friendship Time Budget?
We talk endlessly about the quality of our relationships, but quality cannot exist without time. Time is the one non-renewable input in any friendship — and unlike money or attention, it cannot be borrowed or saved up. A friendship time budget is simply the practice of making that constraint visible: how many hours per week do you actually have for social life, and where are those hours going?
The premise is not that you should optimise your friendships like a spreadsheet. It is the opposite: when you see clearly how scarce your social time really is, you are better equipped to make deliberate choices rather than letting the loudest or most convenient relationships absorb everything by default.
The 40/35/25 Rule, Explained
Robin Dunbar's research — most famously in his 1992 paper on neocortex size as a constraint on primate group size (Journal of Human Evolution, 22(6), 469–493; DOI: 10.1016/0047-2484(92)90081-J) — established that human relationships organise naturally into concentric layers: a support clique of roughly 5, a sympathy group of roughly 15, and a broader close-friends layer of roughly 50.
What Dunbar and his colleagues subsequently discovered is that the time you invest in these layers follows a consistent pattern: the innermost layer (support clique) absorbs approximately 40% of your total social time, the sympathy group roughly 35%, and the broader friends layer around 25%. This is sometimes called the 40/35/25 rule. It is not a prescription — it is a description of how stable, healthy social networks tend to allocate time empirically.
Subsequent studies in the Dunbar research corpus, using both communication-frequency data and self-reported intimacy ratings, have confirmed that the most stable friendships receive the most consistent contact time, and that time investment is the single strongest predictor of which relationships persist across life transitions.
Per-Layer Healthy Minute Bands
Time per person — not time per layer — is what determines whether a relationship can survive. Research within the Dunbar corpus has derived rough contact-frequency norms for each layer — figures we encode as the healthy bands below. Translated into monthly minutes per person, the research suggests:
- Support Clique (inner 5): Roughly 6–10 hours per person per month. These are the people who constitute your emotional bedrock — the investment is substantial and should be. If this number drops below 3–4 hours a month, relationships in this layer tend to migrate outward over time.
- Sympathy Group (close 15): Roughly 1–3 hours per person per month, or one meaningful interaction every two to four weeks. These friendships are resilient to gaps, but they need regular enough contact that shared context is maintained.
- Good Friends (regular 50): Roughly 15–60 minutes per person per month. A single message, a short call, or a brief catch-up suffices — but it does need to happen. Silence for more than 6–8 weeks starts to erode the sense of mutual investment.
This calculator flags layers whose per-person minutes fall outside these bands. The flags are informational, not prescriptive — they are invitations to notice, not verdicts on how you are living.
How to Read the Flags
The calculator can surface two kinds of flags for any layer:
- Over-invested: You are allocating more time per person to this layer than the research bands suggest. This often happens when the total friend count in a layer is very small — say, two people in your "close 15" slot. It is not necessarily a problem; it may simply reflect a life stage (new parent, recent move, intensive care situation). The flag is a nudge to ask: is this the allocation I am choosing, or the one that happened to me?
- Under-invested: The minutes per person per month fall below the threshold for this relationship type to remain meaningfully alive. This is the more common warning in busy adult lives — especially for the sympathy group, where 10–15 people represent a large maintenance commitment. The practical question is not "feel guilty" but "which of these 15 can I schedule a real conversation with this month?"
What This Calculator Is Not
A few honest caveats worth making explicit:
- It is not a verdict. A low minutes-per-friend number for your sympathy group does not mean those friendships are failing. Some relationships are robust to long pauses; others are not. You know which is which. The calculator does not.
- It does not account for quality. Two hours of genuine attention is worth more than eight hours of distracted co-presence. The calculator measures only quantity, because that is what research can reliably measure. Interpret the numbers with that limitation in mind.
- It is not a guilt machine. If your numbers look "bad" — very low minutes across the board because you are in a demanding life phase — the response is not self-reproach. It is the recognition that this is a season, and a reason to make even small intentional gestures matter more.
- The layer boundaries are approximate. Not everyone has exactly 5 people in their support clique or exactly 15 in their sympathy group. The research describes averages. Your network may be structured differently — and that is fine.
From Budget to Action
Seeing your time allocation is only useful if it prompts something. A few practical moves that tend to work:
- Anchor the inner five. If your support clique is getting less than the healthy band, schedule one person from that layer this week — not a group event, but a one-on-one. Research consistently shows that bilateral, synchronous contact (call, in-person) is more relationship-maintaining than group interactions.
- Batch the sympathy group. Fifteen people are too many to maintain via individual scheduling alone. Consider a recurring dinner, a shared group activity, or even a group thread that you actually participate in. Group interactions count — they are less intimate, but they reset the "last contact" clock.
- Protect the good friends floor. The 50-person layer is the most vulnerable to attrition in busy periods, because its members feel like they can wait. They can — but only for so long. A brief, warm message once a month is enough to maintain most of these connections. It costs 90 seconds.
Endearist is designed to help you act on exactly this kind of structure — with gentle, non-intrusive reminders that feel like human attention rather than a task manager. When it launches, your time budget can become a living thing rather than a one-time calculation. Join the waitlist to be first to know.