Funding calculations¶
The funding projection divides remaining needs into daily allocations, using cash that has not already been assigned. It works toward each envelope's nearest planned date, then moves on to the next.
Start with available cash¶
The browser timeline begins with:
Available funds = bank and cash balances - positive envelope balances - cash reserved for card payments, with a minimum of zero.
Only the positive part of each envelope balance counts as assigned cash. An envelope at -$25 creates a funding need; it does not create $25 of extra available money.
Card reserves include cash backing outstanding purchases and money set aside directly for the card, capped at the amount owed. Card borrowing capacity does not contribute cash.
Nightly funding additionally includes positive card balances as prepaid spending value. The current browser timeline and manual funding controls omit that value from their starting available funds, so the browser and nightly process can differ when a card has credit. This does not make the credit available in a bank account. See Positive card balances and available funds.
A small worked budget¶
Suppose today is September 14, with:
- $1,000 in a bank account.
- $100 already funded in Groceries.
- $0 in Phone and no card debt or reserves.
- A $300 Groceries target dated September 17.
- A $65 Phone expense dated September 16.
Available funds start at $900. The browser projection begins September 15.
| Projection day | Phone allocation | Groceries allocation | Available funds after allocations | What is assumed spent that day |
|---|---|---|---|---|
| September 15 | $33 | $67 | $800 | Nothing |
| September 16 | $32 | $67 | $701 | $65 Phone expense |
| September 17 | $0 | $66 | $635 | $300 Groceries target |
Groceries starts with $100 and receives $200 more. Phone receives $65. After both needs are covered, Left to plan is $635.
The assumed spending affects projected balances only. The actual phone transaction still needs to be recorded, and actual grocery purchases need to keep the remaining allowance current.
Calculate a daily allocation¶
For the nearest planned date in an envelope:
- Add the expense amounts due that day and the target allowance for that day.
- Subtract the envelope's working projected balance to find the remaining need.
- Count the calendar days from the allocation day through the planned date, including both ends.
- Calculate the allocation using the rules below.
| Remaining need | Allocation |
|---|---|
| Zero or less | $0 |
| Any positive amount on the planned date | The exact remaining amount |
| Cents in the working balance before the planned date | Prefer an allocation that restores a whole-dollar balance while leaving enough for later days without increasing their allocations |
| $1.00 or less | The exact remaining amount, unless it can be split into a whole-dollar balance adjustment and a smaller final amount |
| Whole-dollar balance before the planned date | Remaining need divided by remaining days, rounded up to the next whole dollar |
For Groceries on September 15, the gap is $300 - $100 = $200 across three days. $200 / 3 rounds up to $67. On the next day, the gap is $133 across two days, which also rounds up to $67. The final $66 is allocated on the due date.
With $0.37 already in an envelope and $10.51 needed across three days, the allocations are $4.63, $3.00, and $2.51. The balance returns to $5.00 on the first day and reaches $8.00 on the second day. The final allocation completes the exact plan before its amount is deducted.
Money is tracked in cents. Funding normally uses whole dollars between the first balance adjustment and the final remainder. Amounts do not increase while funding the same planned date, and a $65.25 bill still receives exactly $65.25. If a simulated purchase introduces new cents, the next allocation restores a whole-dollar balance as soon as it can without increasing funding.
If the working balance is negative, the allocation must also be enough to bring it to zero. Use the larger of that exact deficit and the daily allocation above, rather than adding the two amounts. With ten funding nights remaining for a $100 target, a -$5 balance receives $11 on the first night and ends at $6; a -$50 balance receives $50 and ends at zero. Later nights recalculate normally. Without a future dated plan, fund only enough to reach zero. If available cash cannot cover the full allocation, the usual shortfall rule applies.
Move from one need to the next¶
On a planned date, the projection subtracts that day's target and expenses from the working envelope balance after funding. Funding toward the next date begins on the following projection day.
Any surplus already in the envelope remains available for later needs. For example, $350 already in Groceries covers a $300 target and leaves $50 toward the next one.
Relate the calculation to Left to plan¶
When every required allocation succeeds, Left to plan is the available cash remaining at the end of the forecast. It considers later active plans as well as the part of the timeline currently visible.
If a required step exceeds the remaining cash, funding reaches a limit and the displayed amount becomes zero. The shortfall details preserve how much was needed and how much was actually left at that step. Zero is therefore not always the result of an exact division of every cent.
Continue with Projection rules and edge cases.