Yahoo Finance quotes collected by this site's server every 5 minutes (Korean indices may be delayed) · not investment advice
Real prices for indices like KOSPI and the S&P 500 and large caps in Korea, the US and Japan: buy/sell signals, comparisons, sector heatmaps, monthly returns, crash and recovery history, backtests and DCA, plus stock calculators and light-hearted investing games.
The numbers are the part of investing most often handled by gut feel. What your average cost really becomes after averaging down, what a dividend leaves you after tax, whether a price is expensive relative to earnings, and what selling will cost you — getting those four right meaningfully improves decisions. These tools do the arithmetic for you.
36 markets at once: KOSPI, S&P 500 and other indices, FX, gold, oil, US yields, VIX and Bitcoin, with returns and 52-week range. Yahoo Finance data. Not advice.
Pick an index or stock for a year-by-month returns heatmap, how often each month rose, weekday effects and a Sell in May check. Yahoo Finance data, not advice.
Drawdowns of the S&P 500, KOSPI, Nikkei or any stock from full daily data: past declines, recovery times and returns a year later. Yahoo Finance, not advice.
1D to 1Y returns of 11 US and 14 Korean sector ETFs on a color grid, with excess return vs the S&P 500 or KOSPI. Yahoo Finance data; not investment advice.
How Bitcoin and Ether moved with the Nasdaq, S&P 500, KOSPI, gold, the dollar, US 10Y yield, oil and USD/KRW: correlation bars, matrix, rolling chart. Yahoo Finance data, not advice.
Gold and silver in won, yen or dollars, refreshed every 60s: per gram, don (3.75 g), ounce or kg, 18K/14K value, daily move split, 10-year chart. Not advice.
USD/KRW, EUR/USD, USD/JPY and 13 more FX rates from Yahoo Finance: daily change, intraday to all-time charts, returns and a converter. Not bank rates or advice.
KOSPI, KOSDAQ, S&P 500, Nasdaq, Dow, Nikkei, USD/KRW, gold, WTI, US 10Y and BTC/ETH: closes, daily changes, 52-week position and large-cap movers from live quotes, every 5 min. Not advice.
Buy, neutral and sell signals from 26 indicators on Korean, US and Japanese stocks, each with its rule, value and track record. Yahoo Finance data. Not advice.
Compare up to 5 stocks, ETFs or indices: returns rebased to 100, CAGR, volatility, drawdown, Sharpe, beta, correlation. Yahoo Finance data, not advice.
Scans 50 Korean and 50 US large caps: day change, 1M return, RSI, MA stack, 52-week high gap, volume and crosses. Yahoo Finance data, not investment advice.
Up to 9 stock and index candle charts on one screen, each with its own timeframe, EMA, Bollinger, volume and RSI(14). Delayed Yahoo Finance data. Not advice.
Enter KO, SCHD, O or any ticker: each dividend, annual totals, 5/10-year dividend CAGR, frequency, TTM yield, growth streak. Yahoo Finance data, not advice.
Pick a stock and backtest MA cross, RSI, MACD and 3 more rules on real Korean, US and Japanese prices (Yahoo Finance), dividends and tax included. Not advice.
Replay monthly or weekly buys of a stock or ETF on real Yahoo Finance prices: total invested, value, return, IRR and max drawdown vs a lump sum. Not advice.
Estimate securities transaction tax and capital gains tax when selling Korean and overseas shares. Rates show their basis year and can be edited; dividend tax is in the separate dividend calculator.
Work out your average cost per share after averaging down or up, plus the breakeven price and the move needed to recover.
Calculate gross and after-tax dividend income, dividend yield and yield on cost from your holdings.
Estimate fair value from EPS, BPS, sector P/E and ROE, then compare it against the current price.
Run a pump syndicate for 10 turns: draft dirty-trick cards to lift a fictional stock and cash out before regulator risk hits 100. A market manipulation satire.
Take 'you' public: answer four questions on learning, crisis, money and strengths as made-up institutions trade on your answers. Starts at $5M; three grades.
A satire game: your 100× long slides toward liquidation on a made-up chart. Spam prayers, average down and cry to see how many seconds you can survive.
Take your life public: age, job, housing and six life stats set your share price, then 10 rounds of random life-event cards move the chart and market cap.
Pick your trading style, asset and current return to get a satirical terminal report on your hopium rate, mental grade and a joke prescription. Not advice.
Pin the stocks you follow — US stocks and indices, plus Korean names like Samsung Electronics and SK hynix — and see prices, changes and mini charts on one screen. Full-screen TV mode; your list stays on this device. Prices may be delayed. Not investment advice.
Buy and sell US stocks and Korean names like Samsung Electronics and SK hynix with virtual KRW and USD. Orders fill only during market hours, with fees and taxes applied; your trades and equity curve stay on this device. Prices may be delayed. No real money. Not investment advice.
Set price-cross, % change and RSI conditions on the stocks you follow; while the page is open you get a sound and browser notification when one is met. US stocks plus Korean names like Samsung Electronics and SK hynix. Prices may be delayed. Not investment advice.
Average cost is total money invested divided by total shares. A common misconception is that adding a little to a halved position pulls the average down sharply; in reality it moves in proportion to the money added. Buy 100 shares at 10,000 then 100 more at 5,000 and your average is 7,500 — still a 50% rally away from breakeven. Averaging down is not a loss-reduction technique, it is a decision to increase exposure to one name.
Dividend yield is dividend per share divided by price. What reaches your account is the after-tax figure. Domestic dividends are withheld at source including local income tax, while foreign dividends are first withheld abroad and then reconciled at home. Also treat an unusually high yield with suspicion — it is often the artefact of a collapsing share price, so check the payout ratio and the durability of earnings.
P/E divides price by earnings per share, telling you the multiple of earnings being paid. P/B divides price by book value per share. High ROE with low P/B is a classic screen for relative undervaluation. Normal ranges differ enormously by sector, though — a growth company on 30x and a bank on 6x cannot be judged by the same yardstick. Always compare within a sector and against the company's own history.
Selling domestic shares incurs a transaction tax, gains on foreign shares are subject to capital gains tax after an annual deduction, and dividends are taxed at source. Rates and thresholds change with tax reform, so every rate in these calculators is editable. Always verify the current rules before filing.
It lowers your average price but not the money already lost, and it raises the amount at risk in that one position. Add only after answering whether your view of the business still holds.
No. P/E also looks low when earnings were temporarily inflated or when the market expects them to fall. Judge it against sector peers, the company's own history and the quality of its earnings.
It depends why the yield is high. A yield inflated by a collapsing price can be a warning, and a payout ratio stretched beyond earnings often precedes a dividend cut.
Defaults reflect commonly cited figures, but tax law changes often. Every rate is editable — confirm the current rate with the tax authority or your broker before filing.
No. These calculators and notes are educational reference only and never a recommendation to buy or sell any security.