How to Split Equity Between Co-Founders Fairly

Use contribution tracking, vesting schedules, and equity formulas to split founder ownership based on value brought to the business.

  1. Quantify each founder's capital contributions. List every dollar each founder puts in: initial cash, equipment, IP transfers, personal guarantees on loans. Assign dollar values to non-cash contributions like existing customer lists, proprietary technology, or critical licenses. This becomes your baseline contribution ratio.
  2. Calculate opportunity cost differentials. Compare what each founder gives up to join: previous salary, equity in other companies, or business opportunities declined. The founder leaving a $200K job deserves more equity than one leaving a $75K job, all else equal. Factor this into your split as ongoing sweat equity value.
  3. Weight role criticality and replaceability. Score each founder's role on market scarcity and business impact. A technical founder building proprietary IP typically merits 40-60% equity even with equal cash contributions. A sales founder with industry relationships might command similar weight. Use market salary data to validate these weightings.
  4. Apply the equity formula with founder premiums. Combine contribution ratios, opportunity costs, and role weights into percentages. Add a 10-20% 'founder premium' to the lead founder or CEO who initiated the company. Ensure no founder drops below 10% unless they're truly junior, and cap any single founder at 60% to preserve motivation.
  5. Structure 4-year vesting with 1-year cliffs. Require all founders to earn their equity over 48 months, with 25% vesting after 12 months and monthly vesting thereafter. Include acceleration clauses for involuntary termination or company sale. This protects against early departures and aligns long-term commitment.
  6. Draft buyback provisions for departing founders. Set repurchase terms for unvested shares (typically at cost) and vested shares (at fair market value or formula-based pricing). Include right of first refusal on any founder trying to sell externally. Document everything in a founders' agreement before issuing shares.