Journal
A planning site, not another tracker
A tracker tells you where money went. A plan tells you whether income, saving, and spending still reach the life you said you wanted. Arc is built for the second question. The public tools exist so you can try a piece of it before you build the whole thing.
Arc · Published September 18, 2026 · Updated September 18, 2026
The gap
Most consumer finance products are ledgers. They categorize restaurants and celebrate a month under budget. Useful, and incomplete. A household can track every dollar and still have no idea whether age 60 is funded.
Planning starts from a balance sheet and a year of cash flow, then rolls both forward under assumptions you can read. If the assumption is wrong, you change it. You do not need a new app category for each question.
Why the free tools are incomplete on purpose
The FIRE calculator does not know your mortgage. The match calculator does not know your spending. Publishing them anyway is the point: the math should be visible before anyone creates an account. The moment of upgrade is when you want those answers to share a household, not when a gate drops in front of the formula.
Keep going
Related reading
What is a FIRE number?
A FIRE number is annual spending divided by the withdrawal rate you are willing to use.
Related reading
What is a good savings rate?
A useful savings rate is the one that reaches your spending target on your timeline.
Related reading
Can I afford to quit my job?
Quitting is a cash-flow question first, and a portfolio question only if the break is long.
Tools
Retirement calculator
Project a nest egg from savings, contributions, and a real return, then compare it with spending.
Tools
Years to FI calculator
Estimate how long invested assets and contributions take to reach a FIRE number.
Tools
Savings rate calculator
Divide savings by gross or take-home income and see the rate explicitly.
Playbooks
Raise your savings rate
A general way to lift the share of income you keep, without a personality transplant.
Educational estimate only. Not tax, legal, or investment advice, and not a prediction of what your accounts will do. Methodology