Naive Forecast Tool Calculator

Choose naive, seasonal, mean, or drift forecasts instantly. Set horizon and test size for validation. See tables, errors, and practical guidance in minutes today.

Calculator inputs

Time series Enter numbers separated by commas, spaces, or new lines.
Tip: Keep values in time order, oldest to newest.
Model options
Seasonal naive repeats last season’s pattern.
How many future points to predict.
Example: 12 for monthly seasonality.
Last points reserved for backtest evaluation.
Shown next to results for clarity.
Uncertainty
Uses residual variation as a simple guide.
Result appears above this form, below the header.

Formula used

Let the time series be y₁, y₂, …, yₜ.
Naive forecast
ŷt+1 = yt
Assumes the next value equals the most recent value.
Seasonal naive forecast (period m)
ŷt+1 = yt+1−m
Repeats the value from the same season last cycle.
Mean forecast
ŷt+1 = average(y1..t)
Uses the historical average as a stable baseline.
Drift forecast
Slope = (yt − y1) / (t − 1)
ŷt+h = yt + h × Slope
Extends the long-run average change per step.
Accuracy metrics (on test points)
Error = y − ŷ
MAE = average(|Error|)
RMSE = sqrt(average(Error²))
MAPE = average(|Error / y|) × 100%
sMAPE = average( 2|Error| / (|y|+|ŷ|) ) × 100%
MASE = MAE / average(|Δy|) (or seasonal Δ if m)

How to use this calculator

  1. Paste your observations in time order, oldest first.
  2. Select a baseline method: naive, seasonal, mean, or drift.
  3. Choose the forecast horizon to generate future steps.
  4. Set a test size to evaluate accuracy on recent points.
  5. Optional: enable intervals and select a confidence level.
  6. Press calculate to view results above and download reports.

Example data table

Sample observation series used by the example button.
Index Value Comment
1120Starting level
2128Early increase
3133Small growth
4129Minor dip
5140Rebound
6145Continued rise
7149Stabilizing
8152Gradual increase
9160Peak shift
10158Short pullback
11166New high
12171Latest observation

Related Calculators

Holt Winters ToolDifferencing CalculatorAnomaly Detection ToolFourier Transform ToolSpectral Density ToolChange Point DetectorGranger Causality ToolState Space ModelKalman Filter Tool

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.