How Safe to spend works

The formula

Each part is rounded to whole dollars before it's subtracted, the same way the month's totals are shown, so the figures always add up on screen. “This month” and “today” follow your household's own time zone.

Each part

• Income expected this month. Your paychecks due this month, or what has already come in if that's more. If your pay doesn't arrive on a schedule (regular deposits cover less than about 70% of a usual month, as with freelance work), it's the largest of your recent whole months' average, your regular deposits, and what has come in so far.
• Bills and subscriptions. The largest of: your usual month of bills and subscriptions, the ones due this month, what you've already paid, and your bills budget if you set one. A yearly bill is set aside for a little each month, and a month with more due than usual counts what's due.
• Essentials. Groceries, gas and other needs that vary. With a budget, it's your budget, or what you've spent if that's more. Without one, it's what you've spent so far plus your usual pace for the days left, capped at a usual month (unless you've already spent more than that).
• Savings. Your savings plan: the savings budget you set, or the regular transfers to savings Openbox Money has found. If you've already saved more, it's what you saved. When this month's saving is more than the largest of your plan, your usual month's saving and what this month's income leaves room for, by at least $1,000 or a quarter of the month's income, whichever is more, that extra part counts as money you already had, so it isn't taken out of this month.
• Optional spending so far. Restaurants, shopping, entertainment and the like: what you've spent, not a budget.
• Not yet categorized. Spending is still spending, so anything without a category yet counts too.

Never below $0

Nothing is safe to spend when more is going out than coming in, so Safe to spend never shows a negative number. It shows $0, and the line under it says by how much, as a positive amount: “$258 more going out than coming in”. A shortfall under a dollar shows as plain $0.

The line under the figure

• Mid-month, it shows the days left (counting today) and a daily amount: Safe to spend divided by the days left, rounded to whole dollars. Less than 50 cents a day reads “under $1/day”, never “$0/day”.
• On the last day of the month, plans give way to what happened: income is what came in, and bills, essentials and savings are what was paid, plus anything still due that day. The figure then matches what's actually left over.
• If Openbox Money can't see any income yet, it asks you to connect the account your pay goes into instead of guessing. If the month's expected income is $0 and nothing is expected to go out, it says it needs income history to estimate; if something is, it shows $0 and how much more is going out than coming in.

A worked example

Made-up numbers in the shape of the app's sample household: two paychecks a month, a mortgage and the usual bills, groceries and gas, and $750 a month moved to savings. It's the 15th of a 30-day month, so 16 days are left, counting today. No essentials budget is set: $390 has gone on groceries and gas, and the usual pace for 16 more days adds $400. Together that's $790, more than a usual month of $750, so essentials count as $750.

Now say a $1,900 trip goes on a card the same day. It's optional spending, so it's counted right away:

What it isn't

Safe to spend is an estimate from your own accounts and categories, so it's only as good as they are: a bill filed as optional spending, or a paycheck that comes late, changes it. It isn't financial advice. Questions about it go to support@openboxmoney.com.

Written by Travis Haggar. I build Openbox Money. I'm not a financial adviser. How these guides are written is in our editorial policy.