Best portfolio backtesting tools: 8 compared and tested

Written by the Tactfolio research teamPublished Updated 7 min read

A portfolio backtesting tool shows how a mix of investments would have done in the past. We compared eight of them. For testing a fixed mix for free, Portfolio Visualizer and testfol.io are hard to beat. If you want to write your own rules and then run them, look at Tactfolio. We make Tactfolio, so read our notes with that in mind. Every fact about the other tools comes from their own websites, checked on October 16, 2026.

How we tested#

On October 16, 2026, we ran the same two tests on the tools that let anyone run them for free. We set every tool the same way and wrote down what it showed.

Test 1: a 60/40 portfolio. We put $10,000 in 60% SPY and 40% AGG, rebalanced once a year, from January 2017 to December 2025. We used this window because Portfolio Visualizer’s free plan shows only 10 years.

ToolDataEnd balanceYearly growth (CAGR)Worst drop
Portfolio VisualizerMonthly$23,4339.92%-20.11%
testfol.ioDaily$23,4339.92%-20.99%

Both tools agree to the dollar on growth. You can check a yearly growth rate with our CAGR calculator. The worst drop is deeper on daily data. The 2020 crash hit bottom on March 23, in the middle of a month, and monthly data can’t see that day. How to read a backtest explains drawdown.

Test 2: a timing rule. We ran Mebane Faber’s 10-month rule over the same years. It holds SPY while SPY is above its 10-month average, and BIL, a Treasury bill fund, when it is not. Portfolio Visualizer runs this as a preset model. Tactfolio runs it as a classic strategy.

YearPortfolio VisualizerTactfolio
201721.7%21.7%
2018-6.1%-6.4%
201910.6%10.3%
202014.7%14.5%
202128.8%28.7%
2022-20.1%-20.5%
20239.6%9.3%
202424.9%24.9%
202512.5%12.3%

The two tools agree within half a point every year. Tactfolio comes out a little lower in years when the rule switched. That is its trading cost. Tactfolio charges 0.05% on every trade, and Portfolio Visualizer’s model has no cost setting.

What we did not test: Composer, Portfolio123, and QuantConnect need an account, and QuantConnect and Backtrader need code. For those, we read their own pages and help docs. Tactfolio needs a free account to run a custom mix, so it is not in test 1. To test your own mix there, start with our portfolio backtest form, which opens it in the builder.

The 8 tools at a glance#

ToolBest forDataYour own rules?Trades for you?Price
Portfolio VisualizerDeep analysis of a fixed mixMonthly, asset classes from 1972Preset models onlyNoFree plan with 10 years, paid $30 or $55 a month, billed yearly
testfol.ioFree daily backtests with long historyDaily, simulated back to 1885Signal rulesNoFree, paid from $15 a month
TactfolioWriting your own rules and running themDaily, or hourly for crypto perpsYes, visual blocksYes, in your Alpaca accountFree, Plus $12 a month ($99 a year), Pro $29 a month ($249 a year). Everything is free until billing opens. See pricing
PortfolioChartsLong-term planning for simple portfoliosYearly, asset classes from 1970NoNoFree
ComposerNo-code strategies in one app that is also your brokerDaily, up to 30 yearsYes, visual blocksYes, as your brokerFree to build and backtest
Portfolio123Picking stocks by company dataPoint-in-time company dataScreens and ranking rulesYes, at Interactive Brokers or TradierFree tier, paid from $35 a month
QuantConnectProgrammers who want every marketDown to single tradesYes, Python or C#Yes, about 20 brokersFree plan, paid seats from $10 a month
BacktraderPython coders who want a free libraryWhatever data you bringYes, PythonThrough your own codeFree and open source

Portfolio Visualizer#

Portfolio Visualizer is the classic tool for testing a mix of funds or asset classes. It also has Monte Carlo, optimization, efficient frontiers, and factor regression. Its asset-class data starts in 1972. Most of its backtests use monthly returns. It has preset timing models, like moving averages and dual momentum, but you can’t write new rules. The free plan allows up to 15 assets and shows 10 years. Paid plans cost $30 or $55 a month, billed yearly. It does not trade. Read Tactfolio vs Portfolio Visualizer.

testfol.io#

testfol.io is a newer backtesting site that runs on daily data. Its free tools show the full history of every fund, and simulated tickers reach far back, such as SPY to 1885. A free account adds a tactical backtester, factor regression, and more. Paid plans cost $15, $30, or $100 a month. They raise the limits on optimizers and Monte Carlo runs and add email alerts. The $100 plan includes an MCP server, so an AI assistant can run its tools. It does not trade, and the site does not name the company behind it. Read testfol.io alternatives.

Tactfolio#

Tactfolio is a platform where you build rules-based investing strategies, backtest them on decades of real prices, share them, and run them automatically in your own Alpaca account. You can build by hand in a visual builder or by asking an AI assistant.

Tactfolio backtests on daily prices and charges 0.05% on every trade. Each backtest also shows a line that trades at the next day’s open, so you can see how much timing matters. Young funds can get a clearly labeled simulated history. Its free tools include a Monte Carlo simulator, an efficient frontier, and a portfolio optimizer. It runs long-only strategies on US-listed stocks and ETFs, and it can also backtest crypto perps on Hyperliquid. It has a Free plan, and every feature is free until billing opens.

PortfolioCharts#

PortfolioCharts is a free site by one independent investor who goes by Tyler. It studies simple, long-term portfolios with yearly returns for asset classes, back to 1970, in 12 home countries. Its charts focus on what a saver would live through, such as the worst stretch to wait out and safe withdrawal rates. It does not test single funds or timing rules. Its own FAQ notes that yearly data shows milder drops than daily data, which matches our test 1.

Composer#

Composer is a no-code app for building and trading strategies. You build with blocks or by chatting with its AI. Backtests use daily adjusted closes, up to 30 years back in the editor. Building and backtesting are free on every plan. To trade, you open a Composer brokerage account, because Composer is also the broker. Live trading is for US residents. Read Tactfolio vs Composer.

Portfolio123#

Portfolio123 is built for picking stocks by company data, like earnings and value. You build screens and ranking systems with no code, then backtest them on point-in-time data. That means the backtest only sees numbers that were public on each date. It covers US, Canadian, and European stocks. Paid plans run from $35 to $278 a month. It can send orders to Interactive Brokers or Tradier.

QuantConnect#

QuantConnect is a cloud platform where you write strategies in Python or C#. It covers stocks, options, futures, forex, and crypto, with data down to single trades. The free plan includes backtesting but not live trading. Paid seats start at $10 a month, and most people also pay for computing time. It connects to about 20 brokers. Read Tactfolio vs QuantConnect.

Backtrader#

Backtrader is a free, open-source Python library for backtesting. You bring your own price data and write every rule in code. Its docs cover live trading through Interactive Brokers, Oanda, and Visual Chart. Its last release on PyPI came out in April 2023, so expect to fix things yourself. It suits Python coders who want full control at no cost.

How to choose#

  • To study a fixed mix in depth, with Monte Carlo and optimizers, try Portfolio Visualizer.
  • For free daily backtests with long history, try testfol.io.
  • To write your own rules and have them trade, try Tactfolio.
  • To plan a lazy portfolio for decades, try PortfolioCharts.
  • For one app that builds, tests, and holds your money, try Composer.
  • To rank single stocks by company data, try Portfolio123.
  • If you code, try QuantConnect, or Backtrader for a free library.

Whatever you pick, a backtest only shows the past. Why past results mislead explains what to watch for.

Common questions#

Is there a free portfolio backtesting tool?#

Yes, several. For a fixed mix, testfol.io is free with daily data and full history. Portfolio Visualizer’s free plan has more analysis tools but shows only 10 years. For your own rules, Tactfolio has a Free plan with unlimited backtests.

Why do backtesting tools show different results?#

They use different data, costs, and timing. In our test, two tools agreed on growth to the dollar. But the worst drop differed by almost a point, because one uses monthly data and the other daily. Trading costs also lower a result a little each time a strategy trades.

Is monthly or daily data better for a backtest?#

Daily data shows the real worst drop, because it sees every low point. Monthly data is fine for long-term growth, but it can make drops look smaller. In our 60/40 test, the worst drop was -20.11% on monthly data and -20.99% on daily data.

Can a backtesting tool also trade for me?#

Some can. Tactfolio runs a strategy in your own Alpaca account. Composer trades as your broker. Portfolio123 and QuantConnect can send orders to outside brokers. Portfolio Visualizer, testfol.io, and PortfolioCharts are for research only.

Sources