OSHA 300A Annual Summary: Deadlines, Calculations, and Common Mistakes

The OSHA Form 300A — the "Summary of Work-Related Injuries and Illnesses" — is a single-page form that distills your entire year of recordkeeping into a handful of totals. Unlike the 300 log, which lists each individual case, the 300A shows only aggregate numbers: how many cases occurred, how many involved days away or restriction, how many total days were lost, and how many hours your employees worked. It must be completed, certified by a company executive, and posted where your employees can see it every year.

The form is straightforward, but the process around it has more requirements than most employers realize. There are three separate deadlines, a specific list of people who are legally authorized to sign it, an official formula for average employment that is frequently substituted with something else, a total-hours calculation that payroll data quietly gets wrong, and — for many employers — an electronic submission requirement that carries its own penalties for noncompliance. This guide walks the whole cycle, ending with a complete worked example from 300 log totals to certified summary.

The Three Deadlines

The 300A cycle involves three dates that recur every year. Missing any of them is a citable violation.

February 1 — Post the Summary

By February 1, you must post the previous year's completed and certified 300A summary in a conspicuous location at each establishment — the same area where you post other employee notices such as the OSHA "It's the Law" poster, minimum wage notices, and similar required postings. Under 1904.32(b)(5), the summary goes "in a conspicuous place or places where notices to employees are customarily posted," and you must ensure the posted copy "is not altered, defaced or covered" for the whole posting period. A locked office that employees do not regularly enter does not qualify.

March 2 — Electronic Submission (If Required)

If your establishment meets the size and industry thresholds for electronic reporting, you must submit your 300A data — and in some cases your 300 and 301 data — through OSHA's Injury Tracking Application by March 2. The ITA opens for submissions on January 2 each year. Establishments with 250 or more employees in most industries, and establishments with 20 to 249 employees in designated high-hazard industries, must submit 300A data. Establishments with 100 or more employees in certain high-hazard industries must also submit case-level 300 and 301 data. Not sure which bucket you fall into? The free ITA submission checker resolves it from your peak headcount and NAICS code.

Two points from OSHA's own ITA guidance that trip employers up. First, a clean year does not exempt you: establishments that meet the reporting criteria must submit their 300A data even if they had zero recordable injuries or illnesses. Second, submitting through the ITA does not replace posting — OSHA's FAQ answers this directly: you still post the paper summary at the establishment.

April 30 — Take Down the Summary

The 300A must remain posted until at least April 30. You may leave it up longer if you choose, but you cannot take it down before this date. The three-month posting window — February 1 through April 30 — gives employees a reasonable period to review the summary.

Completing the Form: Field by Field

The 300A has four sections. Each one pulls data from a specific place, and the numbers must be internally consistent with your 300 log.

Establishment Information

Enter your establishment's legal name, street address, industry description, Standard Industrial Classification (SIC) or NAICS code, and the annual average number of employees — calculated with the official method below, not a guess.

Number of Cases

Transfer the year-end totals directly from your 300 log. The 300A asks for four numbers: total deaths, total cases with days away from work, total cases with job transfer or restriction, and total other recordable cases. These correspond to the classification columns G through J on your 300 log. The four numbers should add up to your total number of recordable cases for the year. If they do not match your 300 log totals, you have an error in one document or the other — find and fix it before certifying.

Number of Days

Enter the total number of days away from work (the sum of all entries in Column K of your 300 log) and the total number of days of job transfer or restriction (the sum of Column L). These are aggregate totals across all cases for the year, counted in calendar days and capped at 180 per case.

Injury and Illness Types

Enter the total number of injuries (from Column M-1 of your 300 log) and the totals for each illness category: skin disorders (M-2), respiratory conditions (M-3), poisonings (M-4), hearing loss (M-5), and all other illnesses (M-6). The sum of all six categories should equal your total number of recordable cases.

The Official Average-Employees Formula (It's Pay Periods, Not Months)

The "annual average number of employees" field has an official calculation method, printed on the optional worksheet page of OSHA's own forms package, and it runs on pay periods:

1. Add up the number of employees your establishment paid in each pay period during the year — all of them: full-time, part-time, temporary, seasonal, salaried, and hourly.
2. Count the number of pay periods your establishment had during the year (26 if biweekly, 52 if weekly), including any pay periods with zero employees.
3. Divide the first number by the second.
4. Round up to the next highest whole number.

The worksheet includes one shortcut and one explicit prohibition. The shortcut: if you pay about the same number of employees every pay period all year, you can simply use that number — the formula exists for headcounts that fluctuate. The prohibition, in the worksheet's own words: you cannot divide the total number of W-2s by the number of pay periods. A W-2 count includes everyone who passed through the payroll all year, so for any business with turnover it overstates how many people worked at once.

OSHA's worksheet also suggests a sanity check worth keeping: the result should look like your establishment on an ordinary day. It should fall between your smallest and largest single-pay-period headcounts. If it doesn't, the calculation went wrong somewhere.

Calculating Total Hours Worked

The 300A requires you to enter the total hours worked by all employees during the calendar year. This is the single most error-prone field on the form, and it has outsized consequences because it is the denominator in your TRIR and DART rate calculations. If your hours are wrong, your rates are wrong — and your rates are what insurers, clients, and OSHA look at.

Include actual hours worked by all employees at the establishment: hourly employees, salaried employees, part-time employees, seasonal employees, and temporary workers whose day-to-day work you supervise. Do not include hours for temporary workers supplied by a staffing agency if the agency supervises them.

Do not include paid time off. Vacation hours, sick leave hours, holidays, and other non-work hours should be excluded — the form's instructions say so explicitly, "even if employees were paid for it." This is where most errors occur: many employers pull hours from payroll systems, which typically report hours paid, not hours worked. Payroll hours will overstate your total hours worked, which deflates your incident rates and makes your establishment appear safer than it actually is. If OSHA discovers the discrepancy, it raises questions about the integrity of your entire recordkeeping program.

A Worked Example: From 300 Log to Certified 300A

Numbers make the mechanics concrete. Cedar Mill Cabinetry is a fictional custom cabinet shop — NAICS 337110, one establishment, biweekly payroll, three salaried staff and roughly two dozen hourly employees whose headcount drifted between 22 and 27 during the year.

The year's 300 log. Cedar Mill recorded three cases:

Average number of employees. Summing the headcount paid in each of the 26 biweekly pay periods gives 637. Then: 637 ÷ 26 = 24.5, which rounds up to 25. (Note what was not done: Cedar Mill issued 31 W-2s during the year because of turnover — dividing 31 by anything, or just writing "31," would have been wrong.)

Total hours worked. Time records for the hourly crew total 43,150 actual hours — overtime included, PTO excluded. The three salaried staff don't clock in, so Cedar Mill estimates 2,000 hours each: 6,000. Total: 49,150 hours.

The 300A fields. Deaths (G): 0. Cases with days away (H): 1. Cases with job transfer or restriction (I): 1. Other recordable cases (J): 1. Total days away (K): 11. Total days of transfer or restriction (L): 18. Injuries (M-1): 3; all illness categories (M-2 through M-6): 0. Cross-check: G+H+I+J = 3 = M-1 through M-6. The totals tie to the log.

The rates this produces. TRIR = (3 × 200,000) ÷ 49,150 = 12.2. DART = (2 × 200,000) ÷ 49,150 = 8.1. Whether those numbers are good or bad for a wood-products shop is a benchmarking question — the rate calculator compares them against published BLS industry averages. What the example shows about small denominators: at 49,150 hours, every single recordable case moves Cedar Mill's TRIR by about 4 points (200,000 ÷ 49,150 ≈ 4.07). Small employers' rates are inherently jumpy, which is exactly why the hours figure under them has to be right.

Certification and posting. Cedar Mill's owner — who qualifies under the executive definition below — examines the 300 log, signs and dates the 300A, and posts it on the shop's notice board by February 1. At 25 employees in NAICS 337110, Cedar Mill also checks its ITA obligation for the March 2 deadline.

Executive Certification

The 300A must be certified — signed and dated — by a company executive before it is posted. This is not a formality. Under 1904.32(b)(3), the certifying executive is attesting that they have examined the OSHA 300 log and reasonably believe, based on their knowledge of the process by which the information was recorded, that the annual summary is correct and complete. OSHA takes the certification seriously, and having the wrong person sign is a frequently cited violation.

OSHA defines "company executive" narrowly under 29 CFR 1904.32(b)(4). Only the following individuals are authorized to certify the 300A:

• An owner of the company (sole proprietorship or partnership)
• An officer of the corporation
• The highest-ranking company official working at the establishment
• The immediate supervisor of the highest-ranking company official working at the establishment

A safety manager, HR director, or plant manager cannot sign the 300A unless they independently qualify under one of the categories above. In a small business where the owner is present and active, the owner should sign. In a large corporation, a corporate officer or the site's highest-ranking official is the appropriate signer. If you are unsure who qualifies, err toward the more senior person.

What If You Find an Error While It's Posted?

Suppose the 300A goes up February 1, and in March you discover a case was misclassified — the log needs a correction, and the posted totals no longer match it. Two things are clear from the regulation's text. You must fix the 300 log itself: the duty to update the log with changed classifications runs through the whole five-year retention period. And you must not alter or deface the posted copy (1904.32(b)(5)) — penciling changes onto the wall copy is the one move the rule expressly forbids.

What the regulation does not contain is an explicit duty to produce and re-post a corrected summary mid-window: 1904.33(b)(2) says updating the annual summary is optional. The conservative practice — and the one that keeps your posted numbers defensible if an inspector compares them to the log in April — is to print, certify, and post a corrected 300A alongside or in place of the original rather than leaving a known mismatch on the wall. Just don't mark up the posted copy itself.

Common 300A Mistakes That Lead to Citations

Beyond the certification issue, inspectors frequently find the following errors when reviewing the 300A:

• Totals on the 300A do not match the 300 log. This is the first thing an inspector checks. If your 300A says 3 cases with days away but your 300 log shows 4, you will be asked to explain the discrepancy.
• The form is not posted, or is posted in a location employees cannot easily access. A filing cabinet in the safety manager's office does not count.
• The form is posted but not certified. An unsigned 300A is an incomplete 300A.
• The posting period is wrong. Some employers post the 300A in March and take it down in April, or only post it during the month of February. The required posting period is February 1 through April 30 — the full three months.
• Multi-establishment employers post a single consolidated summary instead of posting a separate 300A at each establishment. Each establishment with employees must have its own 300A posted on-site.
• Hours worked are pulled from payroll instead of calculated from actual hours. This inflates hours, deflates rates, and calls the accuracy of the entire submission into question.
• Average employment is computed from the W-2 count, or eyeballed. The official method is the pay-period formula above — and the worksheet's sanity check (does the result look like your shop on a normal day?) catches most bad answers.

How the 300A Feeds Into Your Incident Rates

The numbers on your 300A are the inputs for your TRIR and DART rate calculations. Your total recordable cases divided by your total hours worked, multiplied by 200,000, gives you your TRIR. Your DART cases divided by total hours worked, multiplied by 200,000, gives you your DART rate — the Cedar Mill example above runs both end to end. Once your 300A totals are final, our free DART and TRIR calculator will run both figures for you and benchmark them against BLS industry averages. These rates follow your company for years — into insurance renewals, contract bids, and OSHA's own targeting algorithms for programmed inspections.

This is why accuracy matters at every stage. A misclassified case on the 300 log flows into wrong totals on the 300A, which produce incorrect rates, which affect your EMR and your ability to win work. The 300A is the point where all of your recordkeeping discipline — or lack of it — becomes visible in a single set of numbers.

After April 30: The Summary Isn't Done, It's Archived

Taking the 300A down does not end its life. It joins the five-year retention schedule with the rest of the year's records: you keep the 300A for five years following the end of the calendar year it covers, and you must be able to produce it within four business hours if an authorized government representative asks. One asymmetry worth knowing: during those five years you must keep updating the 300 log as cases change, but you are not required to update the stored 300A — it is preserved as the snapshot you certified.

300A Questions, Answered Short

Who can sign the OSHA 300A? Only a company executive under 1904.32(b)(4): an owner (sole proprietorship or partnership), a corporate officer, the highest-ranking company official working at the establishment, or that person's immediate supervisor.

Do I still have to post the 300A if I submitted it through the ITA? Yes. Electronic submission and physical posting are separate obligations; OSHA's ITA FAQ says so explicitly.

Do I submit through the ITA if we had zero recordable cases? Yes — if your establishment meets the size and industry criteria, you submit even for a year with no recordables. (And you post a zeros 300A either way.)

Does a small business have to do a 300A at all? If your whole company had 10 or fewer employees at all times during the last calendar year, you are exempt from routine Part 1904 recordkeeping — no 300 log, no 300A — unless OSHA or the BLS asks you in writing. Severe-injury reporting still applies to everyone.

Can I use my own form instead of OSHA's 300A? An equivalent form is acceptable if it has the same information, is as readable and understandable, and is completed with the same instructions — most recordkeeping software output qualifies on exactly this basis.

When does the ITA open? January 2. The submission deadline is March 2 of the year after the reference year.

Year-End 300A Checklist

• Review your 300 log for completeness: every recordable case entered within 7 days, all classifications updated to reflect final outcomes, all day counts finalized or capped at 180.
• Total each column on the 300 log and verify the arithmetic.
• Transfer totals to the 300A and cross-check: total cases should equal the sum of columns G through J, and should also equal the sum of all Column M categories.
• Calculate total hours worked using actual hours, not payroll hours. Document your methodology.
• Calculate the annual average number of employees with the pay-period formula (sum of employees paid each pay period ÷ number of pay periods, rounded up).
• Have a qualifying company executive review the 300 log, then sign and date the 300A.
• Post the certified 300A by February 1 in a visible location at each establishment.
• If required, submit data through the ITA by March 2.
• Leave the 300A posted until at least April 30 — unaltered, undefaced, and uncovered.

That last sentence is the honest pitch for keeping the log continuously instead of reconstructing it in January. LogStead builds the 300A from the year's log automatically — the totals tie out because they come from the same records — walks the certification step, and then preserves the certified summary as the fixed snapshot the rule intends while the log stays live for corrections. If a stored year's log later changes, the year-close drift check flags that the certified 300A no longer matches, so the mismatch is a known fact instead of an inspection surprise.