Avoid the assumptions that make co-founder work harder.
Eight common co-founder mistakes to watch for: vague roles, mismatched time, untested trust and unclear decisions. Use practical questions and a working trial.
Explore the guide →Make the next founder conversation more concrete.
A clearer number, a useful question or a small working plan can move a conversation forward. Use these tools without creating an account.
Prepare the conversations behind a founder agreement.
Plan roles, ownership questions, intellectual property, decisions and departures before a founder agreement. Create a private discussion brief for legal review.
Explore the guide →Startup runway calculator: make the cash visible.
Calculate startup cash runway, net monthly burn and time to a chosen reserve. Explore a six-month constant-flow scenario privately, with no signup.
Open calculator →Equity dilution calculator: see the ownership change.
Model a simple priced equity round using pre-money valuation, new investment and your current ownership. See post-money value and dilution with clear limits.
Open calculator →Twelve questions to discuss together
Compare working expectations and print a private conversation agenda.
Explore the guide →Try a small project together
Agree a bounded output, responsibilities, check-ins and review.
Explore the guide →Your inputs stay with you.
Calculator values and planning notes are not submitted or saved by these tools. Copying or printing is your choice. Closing or refreshing the page clears entered values. Normal website delivery and operational logs still apply.
The calculators are simplified educational scenarios with visible formulas and limits. The agreement planner collects discussion notes for professional review; it does not create or sign a legal agreement.
Looking for people to build with? Read the co-founder search playbook, explore how Aspair matching works or browse all founder guides.
The next step can be a conversation.
Explain what you bring and the responsibility you want to share. Explore co-founder profiles on Aspair and connect when there is a reason to build together.
Find a co-founder →All startup tools