Most budget apps tell you where your money went. Spew’s forecast tells you where it’s going. Click into the Forecast tab and you see a 24-month projection of your cash flow, with sliders to model what-if scenarios.
This is the feature users tell us changed how they think about money. Here’s how to use it.
Accessing the forecast
Click Forecast in the main nav. You’ll see three things:
- A chart showing your projected balance over 24 months
- A spreadsheet showing monthly income, expenses, and net below the chart
- Scenario sliders on the right panel
How the forecast is built
Spew takes your current data and projects forward using:
- Your recurring bills (what you’ve entered in the monthly grid)
- Your expected income (salary, side hustle, etc.)
- Savings and investment contributions (from your bills grid categorized as such)
- One-off expenses you’ve logged (surprise costs, annual fees, etc.)
- Inflation adjustments (optional, configurable)
It assumes your bills continue as-is unless you tell it otherwise.
Reading the chart
The chart shows your projected checking/savings balance month by month:
- Rising line: you’re building wealth. Income exceeds expenses.
- Flat line: you’re breaking even.
- Declining line: you’re running a deficit. Investigate.
- Dip then recovery: expected (big one-off expense followed by normal months).
Hover any point to see that month’s:
- Total expected income
- Total expected expenses
- Net flow
- Ending balance
The spreadsheet view
Scroll down for a month-by-month breakdown. Shows:
- Income sources for each month
- All bills grouped by category
- Category totals
- Net flow per month
- Cumulative balance
Useful for spotting specific months that will be tight and why.
Running scenarios (the sliders)
Click “Scenarios” on the right panel. You’ll see adjustable variables:
Income adjustments
- Salary raise: “What if I get a 10% raise in September?”
- New job: “What if I take a $15K bump in January?”
- Side hustle income: “What if I start earning $1,000/month extra?”
Drag the slider. The chart updates live.
Expense adjustments
- Rent change: “What if I move to a $500/month cheaper apartment?”
- Car payment: “What if I add a $400/month car loan?”
- Mortgage: “What if I buy a home with a $2,500 mortgage?”
Again, live updates.
One-time events
- Home purchase: lump-sum down payment at a specific month
- Wedding: $X at month Y
- Baby expenses: recurring cost starting at month Z
- Job loss: income drops to $0 for N months
Useful for modeling life events before they happen.
Savings changes
- Increase 401(k) contribution: model what 15% vs 10% looks like
- Emergency fund target: accelerate or spread contributions
- Investment acceleration: more into taxable brokerage
Example: The house-buying scenario
Scenario: you’re considering buying a $450K home in 12 months with 10% down.
Set up:
- Add a one-time “Home Down Payment” expense of $45,000 in month 12
- Add a “Closing Costs” one-time of $10,000 in month 12
- Add a recurring “Mortgage Payment” of $3,100/month starting month 13
- Add “Property Tax” of $400/month
- Add “Home Insurance” of $125/month
- Add “Home Maintenance Reserve” of $375/month
- Remove or reduce your current “Rent” starting month 13
What you see:
- Forecast dips sharply in month 12 (down payment hits)
- Stabilizes or recovers depending on your mortgage vs rent delta
- 24-month endpoint shows whether you’ll be better or worse off
If the forecast shows you ending lower than the baseline (no-house scenario), maybe wait another year and save more.
This is the kind of decision that used to require a spreadsheet and 3 hours. Now it’s 5 minutes of slider-dragging.
See our rent vs buy calculator for the static version of this comparison.
Example: The pay-off-debt scenario
Scenario: you’re deciding whether to attack credit card debt vs contribute more to your 401(k).
Set up:
- Baseline forecast with current 401(k) contribution and current minimum credit card payment
- Scenario A: bump 401(k) contribution from 6% to 12%
- Scenario B: keep 401(k) at 6%, put the extra toward credit card (aggressive snowball/avalanche)
- Compare 24-month ending balances
Usually: aggressive debt payoff wins at current credit card rates (20%+). See our debt payoff calculator for the isolated version of this math.
Example: The side-hustle transition
Scenario: you want to leave your W-2 for freelance.
Set up:
- Baseline: current salary + benefits
- Scenario: drop W-2 salary to $0 starting month 6, add $X/month from freelance
- Add $400/month for self-funded health insurance
- Factor in self-employment tax (higher than W-2 FICA)
See W-2 vs 1099 guide and freelance rate calculator for the tax math to plug in.
The forecast shows whether your target freelance income actually beats your W-2 take-home once benefits and taxes are factored in.
The inflation setting
Toggle “Adjust for inflation” on the forecast. When on:
- Your bills are projected to rise 3% per year
- Your income stays flat unless you manually adjust
This shows the “staying flat” tax, and it’s not small. $5,000/month expenses today become $6,300/month in 10 years at 3% inflation.
Sharing and saving scenarios
Saved scenarios persist to your Spew account. You can:
- Save multiple scenarios with descriptive names
- Switch between them
- Compare side-by-side
- Share a read-only view with a financial advisor, partner, or parent
What the forecast won’t do
- Predict market returns on investments (too variable; we project conservatively)
- Account for unexpected life events (job loss, medical emergency)
- Model tax optimization at an accountant level
- Make decisions for you
It shows you the numbers. You make the calls.
Best practices
Update the baseline monthly. Income changes, bills change. Spend 5 minutes at month-end to make sure the forecast reflects reality.
Use conservative assumptions. Don’t assume 20% raises, don’t assume zero unexpected expenses. Give yourself a 10-20% buffer.
Pair with monthly grid. When the forecast shows a tight month, drill into the grid to see why.
Run scenarios before big decisions. Never sign a lease, take a job offer, or quit a job without running the scenario in Spew first.
Next up
- Audit your subscriptions (they often shift forecast meaningfully): Subscription guide
- Compare Spew to other apps with forecast features: Spew vs Monarch
- Learn the full monthly grid: Grid guide