About PageSpeed Insights | Google Developers

PageSpeed Insights (PSI) reports on the performance of a page on both mobile and desktop devices, and provides suggestions on how that page may be improved. PageSpeedInsights HOME DOCS Language English BahasaIndonesia Deutsch Español Français Português–Brasil Türkçe Русский 中文–简体 日本語 한국어 Signin Makeyourwebpagesfastonalldevices PageSpeedInsights HOME DOCS AboutPageSpeedInsights Languages ReleaseNotes PageSpeedAPI GetStartedAPIReferenceClientLibraries Home Products MaketheWebFaster Insights DOCS AboutPageSpeedInsights PageSpeedInsights(PSI)reportsontheperformanceofapageonbothmobileanddesktop devices,andprovidessuggestionsonhowthatpagemaybeimproved. PSIprovidesbothlabandfielddataaboutapage.Labdataisusefulfordebugging performanceissues,asitiscollectedinacontrolledenvironment.However,itmaynot capturereal-worldbottlenecks.Fielddataisusefulforcapturingtrue,real-worlduser experience-buthasamorelimitedsetofmetrics.SeeHowToThink AboutSpeedToolsformoreinformationonthetwotypesofdata. Real-userexperiencedata Real-userexperiencedatainPSIispoweredbytheChromeUserExperience Report(CrUX)dataset.PSIreportsrealusers'First ContentfulPaint(FCP),FirstInputDelay(FID), LargestContentfulPaint(LCP),andCumulativeLayout Shift(CLS)experiencesovertheprevious28-daycollectionperiod. Inordertoshowuserexperiencedataforagivenpage,theremustbesufficientdataforit tobeincludedintheCrUXdataset.Apagemightnothavesufficientdataifithasbeen recentlypublishedorhastoofewsamplesfromrealusers.Whenthishappens,PSIwillfall backtoorigin-levelgranularity,whichencompassesalluserexperiencesonallpagesofthe website.Sometimestheoriginmayalsohaveinsufficientdata,inwhichcasePSIwillbe unabletoshowanyreal-userexperiencedata. Assessingqualityofexperiences PSIclassifiesthequalityofuserexperiencesintothreebuckets:Good,NeedsImprovement, orPoor.PSIsetsthefollowingthresholdsinalignmentwiththe WebVitalsinitiative: Good NeedsImprovement Poor FCP [0,1800ms] (1800ms,3000ms] over3000ms FID [0,100ms] (100ms,300ms] over300ms LCP [0,2500ms] (2500ms,4000ms] over4000ms CLS [0,0.1] (0.1,0.25] over0.25 Distributionandselectedmetricvalues PSIpresentsadistributionofthesemetricssothatdeveloperscanunderstandtherangeof experiencesforthatpageororigin.Thisdistributionissplitintothreecategories: Good,NeedsImprovement,andPoor,whicharerepresentedbygreen,amber,andredbars. Forexample,seeing11%withinLCP'samberbarindicatesthat11%ofallobservedLCPvalues fallbetween2500msand4000ms. Abovethedistributionbars,PSIreportsthe75thpercentileforallmetrics.The75th percentileisselectedsothatdeveloperscanunderstandthemost frustratinguserexperiencesontheirsite.Thesefieldmetricvaluesareclassifiedas good/needsimprovement/poorbyapplyingthesamethresholdsshownabove. CoreWebVitals CoreWebVitalsareacommonsetofperformancesignalscriticalto allwebexperiences.TheCoreWebVitalsmetricsareFID,LCP,andCLS,andtheymaybe aggregatedateitherthepageororiginlevel.Foraggregationswithsufficientdatainall threemetrics,theaggregationpassestheCoreWebVitalsassessmentifthe75thpercentiles ofallthreemetricsareGood.Otherwise,theaggregationdoesnotpasstheassessment.Ifthe aggregationhasinsufficientdataforFID,thenitwillpasstheassessmentifboththe75th percentilesofLCPandCLSareGood.IfeitherLCPorCLShaveinsufficientdata,thepageor origin-levelaggregationcannotbeassessed. DifferencesbetweenFieldDatainPSIandCrUX ThedifferencebetweenthefielddatainPSIversusthe CrUXdatasetonBigQueryisthatPSI’sdataisupdateddaily, whiletheBigQuerydatasetisupdatedmonthlyandlimitedtoorigin-leveldata. Bothdatasourcesrepresenttrailing28-dayperiods. Performancediagnostics PSIusesLighthousetoanalyzethegivenURL,generatinga performancescorethatestimatesthepage'sperformanceondifferentmetrics,including: FirstContentfulPaint, LargestContentfulPaint, SpeedIndex, CumulativeLayoutShift, TimetoInteractive, andTotalBlockingTime. Eachmetricisscoredandlabeledwithaicon: Goodisindicatedwithagreencircle NeedsImprovementisindicatedwithamberinformationalsquare Poorisindicatedwitharedwarningtriangle Performancescore Atthetopofthesection,PSIprovidesascorewhichsummarizesthepage’ssimulated performance.ThisscoreisdeterminedbyrunningLighthousetocollectandanalyzediagnostic informationaboutthepage.Ascoreof90oraboveisconsideredgood.50to90isascore thatneedsimprovement,andbelow50isconsideredpoor. Audits Lighthouseseparatesitsauditsintothreesections: Opportunitiesprovidesuggestionshowtoimprovethepage’sperformancemetrics. Eachsuggestioninthissectionestimateshowmuchfasterthepagewillloadifthe improvementisimplemented. Diagnosticsprovideadditionalinformationabouthowapageadherestobest practicesforwebdevelopment. PassedAuditsindicatestheauditsthathavebeenpassedbythepage. Frequentlyaskedquestions(FAQs) WhatdeviceandnetworkconditionsdoesLighthouseusetosimulateapageload? Currently,Lighthousesimulatesthepageloadconditionsofamid-tierdevice(MotoG4)device onamobilenetworkformobile,andan emulated-desktopwithawiredconnectionfordesktop.PageSpeedalsorunsinaGoogle datacenterthatcanvarybasedonnetworkconditions,youcancheckthelocationthatthetest wasbylookingattheLighthouseReport'senvironmentblock: Note:PageSpeedwillreportrunninginoneof:NorthAmerica,Europe,orAsia. Whydothefielddataandlabdatasometimescontradicteachother? ThefielddataisahistoricalreportabouthowaparticularURLhasperformed,andrepresents anonymizedperformancedatafromusersinthereal-worldonavarietyofdevicesandnetwork conditions.Thelabdataisbasedonasimulatedloadofapageonasingledeviceandfixed setofnetworkconditions.Asaresult,thevaluesmaydiffer. SeeWhylabandfielddatacanbedifferent (andwhattodoaboutit)formoreinfo. Whyisthe75thpercentilechosenforallmetrics? Ourgoalistomakesurethatpagesworkwellforthemajorityofusers.Byfocusingon75th percentilevaluesforourmetrics,thisensuresthatpagesprovideagooduserexperience underthemostdifficultdeviceandnetworkconditions. SeeDefiningtheCoreWebVitalsmetricsthresholds formoreinfo. WhydoestheFCPinv4andv5havedifferentvalues? FCPinv5reportsthe75thpercentile(asofNovember4th2019),previouslyitwasthe90thpercentile. Inv4,FCPreportsthemedian(50thpercentile). WhydoestheFIDinv5havedifferentvalues? FIDreportsthe75thpercentile(asofMay27th2020),previouslyitwasthe95thpercentile. Whatisagoodscoreforthelabdata? Anygreenscore(90+)isconsideredgood,butnotethathavinggoodlabdatadoesnot necessarilymeanreal-userexperienceswillalsobegood. Whydoestheperformancescorechangefromruntorun?Ididn’tchangeanythingonmypage! Variabilityinperformancemeasurementisintroducedviaa numberofchannelswithdifferentlevelsofimpact.Severalcommonsourcesofmetric variabilityarelocalnetworkavailability,clienthardwareavailability,andclientresource contention. Whyisthereal-userCrUXdatanotavailableforaURLororigin? ChromeUserExperienceReportaggregatesreal-worldspeeddatafrom opted-inusersand requiresthataURLmustbepublic (crawlableandindexable) andhavesufficientnumberofdistinctsamplesthatprovidearepresentative,anonymizedview ofperformanceoftheURLororigin. Morequestions? Ifyou'vegotaquestionaboutusingPageSpeedInsightsthatisspecificandanswerable, askyourquestioninEnglishonStackOverflow. IfyouhavegeneralfeedbackorquestionsaboutPageSpeedInsights,oryouwanttostarta generaldiscussion,startathreadinthemailinglist. IfyouhavegeneralquestionsabouttheWebVitalsmetrics,startathreadintheweb-vitals-feedbackdiscussiongroup. Feedback Wasthispagehelpful? Yes Great!Thankyouforthefeedback. Ifyouhaveaspecific,answerablequestionaboutusingPageSpeedInsights, askthequestioninEnglishonStack Overflow.Forgeneralquestions,feedback,anddiscussion,startathreadinthe mailinglist. No Sorrytohearthat. Ifyouhaveaspecific,answerablequestionaboutusingPageSpeedInsights, askthequestioninEnglishonStack Overflow.Forgeneralquestions,feedback,anddiscussion,startathreadinthe mailinglist. Exceptasotherwisenoted,thecontentofthispageislicensedundertheCreativeCommonsAttribution4.0License,andcodesamplesarelicensedundertheApache2.0License.Fordetails,seetheGoogleDevelopersSitePolicies.JavaisaregisteredtrademarkofOracleand/oritsaffiliates. Lastupdated2022-04-11UTC. 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