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You have 12 months of sales numbers and you need to know where things are heading. A sales forecast calculator takes your historical data, finds the trend, and projects it forward with a confidence range so you know how much to trust the number. No spreadsheet formulas. No $99/month software. Just your data and a result.
Enter your sales data and get a forecast instantly
Open Trend Forecast ToolEvery sales forecast answers one question: if the pattern in my data continues, where do the numbers go? Three methods, different strengths:
| Method | How It Works | Best For | Weakness |
|---|---|---|---|
| Linear Regression | Fits a straight line through all data points and projects it forward. | Steady growth or decline. Most businesses most of the time. | Misses curves. If growth is accelerating, it underestimates. |
| Moving Average | Averages the last N periods and extends with a slight trend adjustment. | Noisy data with lots of month-to-month bounce. | Slow to react to real changes. Lags behind turning points. |
| Exponential Smoothing | Weights recent data more heavily than older data. Adapts faster. | Businesses where growth is speeding up or slowing down. | Can overreact to one-time spikes or dips. |
Start with linear regression. It is the default for a reason. Switch to exponential smoothing only if your growth rate is clearly changing speed.
Simple growth rate method:
Forecast = Last Month Sales x (1 + Average Monthly Growth Rate)
If December = $24,500 and average growth = 6%, then January = $24,500 x 1.06 = $25,970
Linear regression method:
y = a + bx, where b is the slope (growth per period) and a is the starting point. The calculator finds a and b from your data using least squares, then plugs in future x values. It also calculates a confidence band based on how scattered your data is around the trend line.
You do not need to memorize these. Enter your numbers into the forecast tool, pick your method, and it handles everything including the confidence range.
Here is a typical small business entering monthly revenue:
| Month | Revenue | Change |
|---|---|---|
| Jan | $12,000 | — |
| Feb | $13,200 | +10.0% |
| Mar | $11,800 | -10.6% |
| Apr | $15,500 | +31.4% |
| May | $16,200 | +4.5% |
| Jun | $14,800 | -8.6% |
| Jul | $18,000 | +21.6% |
| Aug | $19,500 | +8.3% |
| Sep | $17,200 | -11.8% |
| Oct | $21,000 | +22.1% |
| Nov | $22,800 | +8.6% |
| Dec | $24,500 | +7.5% |
The month-to-month swings look chaotic, but the overall trend is clearly upward — from $12K to $24.5K. The forecast tool cuts through the noise, fits the trend, and projects: approximately $26K-$28K in January, $30K-$34K by June, with confidence bands showing the full range.
| Tool | Price | What It Does | Who Needs It |
|---|---|---|---|
| ✓ Trend Forecast Tool | ✓ Free | Enter numbers, see trend + forecast + confidence band | Any business with historical data |
| Excel FORECAST function | ~$7-10/mo (Microsoft 365) | Manual formula building, no auto confidence bands | People already in Excel who know formulas |
| LivePlan | $20-40/mo | Full business plan + financial projections | Startups writing investor-ready plans |
| Float | $59-199/mo | Cash flow forecasting tied to QuickBooks/Xero | Businesses needing accounting integration |
| PlanGuru | $99/mo | 20 forecasting methods, budgets, consolidation | CFOs and finance teams |
If you just need to see where your numbers are heading, you do not need a $99/month finance suite. Enter your data, get the trend, download the chart.
Every forecast includes a shaded region that gets wider the further out you go. This is the confidence band — the range of likely outcomes based on how much your historical data varies from the trend.
Smart businesses use the lower band for conservative planning (expenses, hiring) and the upper band for optimistic scenarios (revenue targets, stretch goals).
Enter your sales data and see the forecast
Open Trend Forecast Tool