| Metric | Value | Copy |
|---|---|---|
| {{ row.label }} | {{ row.value }} | |
| No metrics yet. | ||
| {{ header }} | Copy |
|---|---|
| {{ cell }} | |
| No detail rows yet. |
| Priority | Recommendation | Rationale | Timeline |
|---|---|---|---|
| {{ row.priority }} | {{ row.recommendation }} | {{ row.rationale }} | {{ row.timeline }} |
| No guidance recommendations available yet. | |||
Growth velocity is the rate of change between visits, not the percentile from a single visit. That distinction matters because a child can stay near the same size band while slowing down, or can cross bands during normal early catch-up. This calculator turns serial visit measurements into annualized interval rates so the pattern is easier to read.
The tool is built for longitudinal height or weight checks. It compares each interval with an expected age-stage rate, shows whether the latest segment looks low, expected, or high, and tracks whether unusual intervals are isolated or repeating. That makes it more useful than a lone measurement when the real question is whether growth is drifting, stabilizing, or catching up.
A familiar example is a child with measurements at 6, 12, 18, and 24 months. The important signal is not just where the last point sits. It is how quickly each interval changed, whether the newest interval is moving in the expected range, and whether earlier low or high segments are forming a streak.
Growth also happens in spurts, which is why interval interpretation needs restraint. One low segment does not prove disease, and one expected segment does not erase a longer low pattern. The tool helps by surfacing streaks, cumulative velocity drift, and interval-by-interval detail instead of asking you to trust only the latest number.
This is an educational growth estimate, not a diagnosis or treatment recommendation. Concerning results still need standardized measurement, the full growth record, and clinical judgment.
For a first pass, keep Visit metric on Height or Weight, paste one numeric row per visit into Visit data rows, and leave Expected-growth stage on Auto by interval age. That gives you a baseline run with the least interpretation friction. If the series is clean, the summary, interval table, stability view, and chart all update from the same rows.
This works best when you have repeated visits from the same measurement stream and enough time between visits for a real growth signal to emerge. It is much less convincing when you have only one measurement, very short intervals, or mixed techniques that make a tape-measure difference look like biology.
Pattern alert appears, open Velocity Stability Lens before reacting to the latest interval alone. The streak signal is often more important than a single bar.Latest interval status is low but Longest low-velocity streak is only one interval, verify spacing and measurement quality before treating it as sustained deceleration.After the first run, use Interval Breakdown to see which segment is driving the summary and then read Velocity Interval Guidance for the follow-up framing.
The calculator parses numeric visit rows, sorts them by age, keeps the latest duplicate age, and converts the tracked measurement into one canonical unit before doing any interval math. Height rows are converted to centimeters, weight rows are converted to kilograms, and every interval is then annualized so a six-month gap and a twelve-month gap can be compared on the same per-year scale.
Expected velocity is based on the midpoint age of each interval, not just the final visit. The package uses a stepped internal rate table for height and weight, then multiplies that base rate by an age-stage factor. If you leave Expected-growth stage on Auto by interval age, the tool applies infant, toddler, childhood, or adolescent multipliers according to the midpoint of each segment. If you choose a preset, that multiplier is forced across the whole series.
Status classification is rule-driven. At the default sensitivity of 1.0, an interval becomes Low when observed annualized velocity falls below 70% of expected and High when it rises above 140% of expected. The calculator then adds a second layer of interpretation by tracking the longest low and high streaks, the cumulative velocity delta across the full series, and a configurable Pattern alert threshold.
One implementation boundary is especially important. The visible WHO, CDC, and hybrid selector is shared with the broader growth tool family, but this velocity view does not recalculate interval expectations from published percentile tables. Its decisive comparison comes from the built-in age-stage rate table, the selected sensitivity, and the streak rule. That makes the tool useful for structured review, but it also means the result should be read as an educational screening aid rather than a formal growth-standard lookup.
Each interval uses a simple annualized rate and then compares that rate with an expected value derived from the interval midpoint.
Here, x is the measured height or weight, m is age in months, and the final multiplier reflects the selected or inferred stage profile. For example, height values of 80.2 cm at 18 months and 86.0 cm at 24 months produce an annualized height velocity of (86.0 - 80.2) / 6 × 12 = 11.6 cm/year.
| Rule element | Package behavior |
|---|---|
| Infant stage | Midpoint age under 12 months or preset multiplier 1.18 |
| Toddler stage | Midpoint age 12 to under 36 months or preset multiplier 1.05 |
| Childhood stage | Midpoint age 36 to under 120 months or preset multiplier 0.92 |
| Adolescent stage | Midpoint age 120 months or higher or preset multiplier 0.82 |
| Low interval rule | Observed velocity < Expected velocity × lowFactor |
| High interval rule | Observed velocity > Expected velocity × highFactor |
| Default sensitivity | lowFactor = 0.70, highFactor = 1.40 at sensitivity 1.0 |
| Pattern alert | Triggered when the longest low or high streak is greater than or equal to Streak alert threshold |
The internal base rates also change by age band. Height starts high in infancy, slows through childhood, rises again in the adolescent spurt, and then tapers. Weight follows the same broad pattern with different units. That is why the midpoint age matters so much more than the last visit age on its own.
| Midpoint age band | Height base rate | Weight base rate |
|---|---|---|
| 0 to under 12 months | 24.0 cm/year | 6.0 kg/year |
| 12 to under 24 months | 12.0 cm/year | 3.0 kg/year |
| 24 to under 36 months | 8.0 cm/year | 2.2 kg/year |
| 36 to under 60 months | 7.0 cm/year | 2.2 kg/year |
| 60 to under 120 months | 5.5 cm/year | 2.6 kg/year |
| 120 to under 156 months | 5.0 cm/year | 3.4 kg/year |
| 156 to under 180 months | 7.5 cm/year | 4.8 kg/year |
| 180 to under 204 months | 4.0 cm/year | 3.0 kg/year |
| 204 to 240 months | 2.2 cm/year | 1.7 kg/year |
The result package is strongest when you read the interval-level outputs together. Latest annualized velocity tells you what just happened, Cumulative velocity delta tells you whether the whole series is running above or below the internal expectation, and Pattern alert tells you whether the concern is repetitive enough to deserve extra attention.
Start with a clean serial dataset and let the baseline run show you whether the concern is isolated or persistent.
Visit metric to Height or Weight and choose the matching unit. The tabs remain empty until the tool has enough rows to compute at least one interval.Visit data rows as numeric age_months,value pairs. If the red alert says Row X: invalid numeric value or Enter at least two visit rows as age_months,value., clean the rows and keep only numeric month values plus one measurement per line.Advanced and leave Expected-growth stage on Auto by interval age for the first run. Adjust Velocity alert sensitivity and Streak alert threshold only after you have seen the baseline summary.Growth Velocity Summary, especially Latest annualized velocity, Expected annualized velocity, and Latest interval status. That tells you whether the newest segment is above, below, or inside the internal expected band.Interval Breakdown and Velocity Stability Lens to see which interval is driving the result and whether Longest low-velocity streak, Longest high-velocity streak, and Pattern alert point to repetition.Velocity Interval Guidance and Velocity Interval Chart to frame follow-up timing and compare observed bars with the expected line. Use JSON if you need the exact assumptions and outputs captured with the run.The best review habit is to keep the baseline rows unchanged and alter only one advanced setting at a time.
The most important reading is the relationship between Latest interval status, Pattern alert, and Cumulative velocity delta. A low latest interval with no streak may represent timing or technique noise. A low latest interval with a repeated low streak and a negative cumulative delta means the whole series is lagging the internal expectation, not just one visit.
Expected plus No sustained deviation streak means the newest interval sits inside the tool’s current band, but it still deserves a quick check of interval spacing and measurement quality.Low or High plus Pattern alert means repeated deviation across intervals. That carries more weight than one unusual segment by itself.Cumulative velocity delta means the series has been trailing or exceeding the internal expectation over time, even if the newest bar looks less dramatic.Do not overread a single Expected result as clearance, and do not treat this tool as diagnostic. Before acting, verify the interval lengths in Interval Breakdown, check measurement technique, and compare the same visits with an attained growth chart or clinical growth record.
Enter Height rows of 6,65.1, 12,74.6, 18,80.2, and 24,86.0 in centimeters. The newest interval produces a Latest annualized velocity of about 11.6 cm/year, Latest interval status stays Expected, Longest low-velocity streak is only one interval, and Pattern alert stays off. That combination says the later toddler intervals fit the tool’s internal range even though one earlier segment was slower.
Enter Weight rows of 24,12.0, 30,12.6, and 36,13.0 in kilograms. The newest interval yields a Latest annualized velocity of roughly 0.8 kg/year against an Expected annualized velocity a little above 2.3 kg/year, so Latest interval status becomes Low. Because both intervals are low, Longest low-velocity streak reaches two intervals and Pattern alert changes to Consecutive interval review needed. That is a much stronger signal than a single low segment alone.
Suppose the rows are pasted as 12 months,74.6, 18,80.2, and 24,86.0. The tool throws the red alert Row 1: invalid numeric value "months". After correcting the series to 12,74.6, 18,80.2, and 24,86.0, the summary and Interval Breakdown return. The lesson is simple: review the parser error first, then interpret the repaired run rather than the failed paste.
Use numeric age_months,value rows. Commas, spaces, semicolons, tabs, and pipe separators all parse, but the first two fields on each line must be numeric. If the same age appears more than once, the latest duplicate row is kept.
Because growth is not perfectly smooth. The tool therefore keeps Longest low-velocity streak, Longest high-velocity streak, and Pattern alert so repeated deviation carries more weight than one isolated segment.
Not in the decisive way many readers expect. In this velocity view, the comparison is driven by the package’s built-in age-stage rate table, sensitivity setting, and streak rule. The selector is shared with the broader growth suite and mainly provides context here.
For dependable results, stay with height or weight series. The outputs and expected bands in this view are expressed as height or weight per year, so it should not be treated as a BMI-velocity reference.
No. This version calculates in the browser and only creates files when you choose to copy or download the current result package.
The tool will compute any increasing interval, but short gaps are easy to overread. Check Pattern alert, the segment lengths in Interval Breakdown, and the measurement context before treating a short interval as biologically meaningful.
This tool is strongest as a structured review aid for serial measurements. It does not replace standardized height or weight technique, the full attained growth chart, pubertal context, symptom history, or a clinician’s assessment of the whole child.
If a result shows a repeated low streak, a high streak with unexpected acceleration, or a pattern that does not fit the child’s broader growth history, treat the tool as a prompt for closer review rather than as a final answer.