What the Relative Strength Index Calculator is for
Calculate simple-period RSI from entered closing-price changes.
It makes the prices, cash flows, rates, time periods, weights, and model conventions explicit so you can inspect an entered scenario without hidden live-market assumptions.
Calculation structure
Follow the stated model and units
RSI = 100 − 100 ÷ (1 + average gain ÷ average loss).
Visual explanation
See how the inputs become the result
Capital and cash flowstime and rate→entered modelScenario resultChanging one assumption changes the model—not the marketRSI = 100 − 100 ÷ (1 + average gain ÷ average loss).
Read the estimate correctly
Use the result within its boundaries
Closing prices 1, 2, 3, 4 over three changes contain gains only and produce RSI 100.
This page uses simple averages, not Wilder's recursive smoothing. A flat selected window reports the explicit neutral convention RSI 50; gain-only reports 100 and loss-only reports 0.
Quick guide
How to use this calculator
Enter observations in chronological order and choose the visible period or convention.
Use prices and volumes with consistent units and equally spaced periods where required.
Read the formula and seeding convention before comparing results with another platform.
Calculation method
Calculation method
RSI = 100 − 100 ÷ (1 + average gain ÷ average loss).
Technical indicators are deterministic transformations of entered historical data. Approximate floating results are explicitly formatted as estimates.
Worked example
Worked example
Closing prices 1, 2, 3, 4 over three changes contain gains only and produce RSI 100.
RSI = 100 − 100 ÷ (1 + average gain ÷ average loss).
Supported inputs
Precision and limits
Visible input limits
Lists accept up to 2,000 fixed-decimal rows. Period fields disclose their whole-number limits. Approximate indicators reject observations whose significant differences cannot be represented reliably at their entered scale.
No live market data
The page does not fetch prices, volumes, corporate actions, exchange calendars, or benchmark data. Enter adjusted or unadjusted observations deliberately.
Decision boundary
Indicators describe entered history. They do not predict price direction, identify a suitable trade, measure every risk, or recommend an investment.
Calculator-specific assumptions
This page uses simple averages, not Wilder's recursive smoothing. A flat selected window reports the explicit neutral convention RSI 50; gain-only reports 100 and loss-only reports 0.
