Time to fill vs time to hire for engineering roles
Every hiring process runs a stopwatch, and the argument is about when you press start. Press it the day the company decides it needs an engineer and you are measuring time to fill. Press it the day your eventual hire applies and you are measuring time to hire. Both stop when that person accepts the offer, so the difference is how long you waited for them to show up.
The two numbers are nested rather than rivals. Time to hire sits inside time to fill, which means most of the time to fill vs time to hire question is really a question about the gap between them. A big gap says the job sat open with nobody worth interviewing. A small gap inside a long total says somebody good applied early and then spent weeks inside your process, which is a different problem with a different fix.
Two clocks with the same finish line
The usual definitions are short. Time to fill counts the days from the approval of a job requisition (the internal form that gives you permission to hire someone) to the day a candidate accepts the offer. Time to hire counts the days from that candidate applying to that same acceptance, as AIHR’s explanation of the two measures lays out. SHRM counts time to fill in calendar days with weekends and holidays included, running from the day the requisition opens until the offer is accepted, according to a SHRM article on time to fill as a staffing metric.
| Measure | Clock starts | Clock stops | What it mostly reflects |
|---|---|---|---|
| Time to fill | Requisition approved | Offer accepted | How long the team went without the engineer it asked for |
| Time to hire | The eventual hire applies | Offer accepted | How long a good candidate spent waiting on your decisions |
| Acceptance to first day | Offer accepted | First day at work | Notice periods, relocation and onboarding paperwork |
Notice that neither standard clock runs to the first day of work. An engineer who accepts in March and starts in May has been filled and hired on paper while the drawings still wait for somebody to do them, so you might keep that third clock too.
The hiring manager should mostly watch time to hire
Time to fill is the number the business feels, because it is the full stretch with an empty seat on the team. But a lot of it is out of the hiring manager’s hands. Budget approval belongs to finance, and the number of power engineers who live within an hour of your plant is not something anyone in your building can change by Thursday.
Time to hire is different. It is made almost entirely of your own calendar: how fast someone reads the application, how long it takes to line up four interviewers, whether the debrief happens this week and whether the offer needs three signatures. It is also the part of the process where you can lose a candidate you already found. Think about what an applicant is from the employer’s side. You paid, in ads or recruiter time or referral bonuses, to get that person to raise their hand. Every extra day they sit in your process is a day in which some other employer can simply offer them the job.
So the hiring manager should own time to hire and be judged on it, while the person who owns the budget should watch time to fill as the cost of the vacancy. If you can only put one number on an engineering manager’s dashboard, put time to hire there, because it is the one that moves when they change their own behavior.
Reading the two together
The useful move is to split time to fill into the days before your hire applied and the days after. Each half points at a different fix.
| Where most of the days went | What it probably means | What to try first |
|---|---|---|
| Before the eventual hire applied | Too few qualified applicants reached you | Widen the search on location or pay and start direct outreach early |
| After the eventual hire applied | Your own scheduling and approvals were slow | Book the interview loop in advance and pre-approve the offer |
| Between acceptance and first day | Notice periods or a move | Plan start dates and relocation support before the offer goes out |
Published benchmarks deserve a loose grip
People searching this topic usually want a number to compare against, and the well-known ones are less helpful than they look. That same SHRM article put the average time to fill across all positions at 33.3 days in research it cited, and the article dates from 2012. It covers every kind of job, so it says little about a senior controls engineer in a tight market today.
The federal government publishes more than most employers do. An inspector general audit of hiring at the Government Accountability Office found that its mission-critical hires took about 103 days on average in fiscal 2024, against OPM’s goal of 80 days for executive branch agencies. The same audit found that the calculations were based on inaccurate dates for when hiring actions began, and it recommended that GAO define which hiring actions belong in the figure. If GAO can lose track of when its own clock started, it is worth checking when yours does.
Neither figure is about engineers, and neither tells you what a good number looks like for your next mechanical design hire. Your own history does. Pull the last several engineering roles you filled, measure both clocks the same way for each and use that as the baseline you try to beat.
How to shorten time to fill
Most of what shortens time to fill happens before anyone applies, which is why it feels like administration rather than recruiting.
- Get the requisition approved before the need turns urgent, because approval days count toward time to fill whether or not anyone is searching yet.
- Write the job around the actual work. An electrical engineering search for power distribution and one for electronics development reach different people, so a vague posting attracts both and satisfies neither.
- Put a real pay range in the posting so that candidates who would turn down your offer can skip the process instead of finishing it.
- Decide on remote work and relocation before the search opens, since each decision changes how many engineers can say yes.
- Call the finalists from your last search for a similar role before posting anything new.
- Start direct outreach the day the requisition is approved instead of waiting to see who applies.
How to shorten time to hire
Once a good engineer has applied, every step is yours, so every step can be made shorter.
- Hold time on interviewers’ calendars for the whole loop when the requisition opens, so that scheduling takes minutes rather than weeks.
- Screen applications within a couple of days and tell people where they stand.
- Use one technical exercise sized to an afternoon. For a mechanical engineering hire, a conversation about one design the candidate took through analysis, prototyping and testing can tell you as much as a take-home project and costs everyone less time.
- Hold the debrief within a day of the final interview and leave it with a decision.
- Get the offer range approved before the final round so a yes can go out the same day.
- Run reference checks while the offer is being prepared rather than after it.
None of these lowers the bar. They only remove the waiting between steps, which is the part of the process that adds days without telling you anything new about the candidate.
Start by logging the dates
For each engineering requisition, record the day it was approved and the day it was posted. Then record the day your eventual hire applied and the days of the final interview and the offer. Finally record the acceptance and the first day of work. With those in a spreadsheet you can compute both clocks for every role and see which half of the wait is bigger. Fix the bigger half first. If most of the days are going to finding people rather than deciding on them, that is the stretch where outside help with an electrical or mechanical engineering search can be worth the fee.
