J. Welles Wilder introduced the RSI in 1978. Readings above 70 are traditionally read as overbought and below 30 as oversold; in strong trends RSI can stay extreme for a long time. Everything is calculated in your browser, so nothing you type is sent to our server.
How to use the Relative Strength Index Calculator
- Closing prices (oldest first)
- RSI period
- Moving-average length
Everything runs in your browser, so results appear instantly and nothing you type is sent to a server.
How it works
Paste closing prices in date order (oldest first) and choose the RSI period and moving-average length.
Formula
Average gain and loss over the first n periods, then smoothed: avg = (previous avg × (n − 1) + current) ÷ n
RS = average gain ÷ average loss
RSI = 100 − 100 ÷ (1 + RS)
Worked example
Inputs: Closing prices (oldest first): 44.34, 44.09, 44.15, 43.61, 44.33, 44.83, 45.10, 45.42, 45.84, 46.08, 45.89, 46.03, 45.61, 46.28, 46.28, 46.00, 46.03, 46.41, 46.22, 45.64; RSI period: 14; Moving-average length: 10.
Results: Relative strength index (RSI) = 57.92; Signal = Neutral; Simple moving average = 46.039; Exponential moving average = 45.8704; Weighted moving average = 46.0576; SMA series (period: value) = 10: 44.779
11: 44.934
12: 45.128
13: 45.274
14: 45.541
15: 45.736
16: 45.853
17: 45.946
18: 46.045
19: 46.083
20: 46.039.
Frequently asked questions
What is the RSI?
A momentum oscillator from 0 to 100 measuring the speed of price changes.
What RSI period should I use?
14 is standard; shorter periods are more sensitive.
What does RSI above 70 mean?
The asset may be overbought.