Here's my actual monthly budget breakdown for how I built a 6-month emergency fund on a $45k salary over about 22 months.

Take-home after tax and 401k contribution: $2,950/month. Fixed expenses: rent $950, car insurance $87, phone $35, internet $45, renter's insurance $12. That's $1,129. Groceries and household: $280. Utilities: $65. Transportation (gas + occasional maintenance): $120. Total fixed + essential: $1,594. Discretionary and entertainment: ~$350. Monthly savings to HYSA: $1,006.

The $1,006/month over 22 months added to my initial $1,000 equals about $23,000 — which was my 6-month target at the time. HYSA interest added another ~$1,200 over that period.

The keys: housing below 30% of gross income, no car payment, and keeping phone/subscriptions ruthlessly low.