When will SSDs be cheaper than hard drives? Based on history, it’s possible to make an educated guess, and I’m going to do it.

Back in 2011, I noticed that historical hard drive pricing fell in line pretty nicely with Moore’s Law, and predicted that SSDs would do the same. I predicted that SSDs would reach 25 cents per gigabyte sometime in 2016, and was wrong. They hit that price in 2015. So I was late by a few months.

But I’m still willing to try to predict when SSDs will cost less than hard drives. I’ll predict when they’ll hit parity too. SSDs work differently from hard drives but their pricing trend is frighteningly similar.

Trailing Moore’s Law

This hard drive from the mid 1980s stored 20 megabytes and cost hundreds of dollars. Compared to this relic, SSDs are already cheap.

Hard drives had a head start, but for the last couple of years they haven’t been following Moore’s Law and it’s possible that trend will continue. Rather than decrease in price by 50% every 18 months, they’ve been decreasing at a rate closer to 17%.

Meanwhile, SSDs have continued to drop at a rate near 50% every 18 months. The faster rate means they can catch up in price if current trends continue. In 2017, prices started increasing, but the overall trend is downward.

I think that in late 2018, SSDs will sell for about 6 cents per gigabyte. That’s about what traditional drives sold for in 2015. I expect traditional drives will be selling for about 4 cents per gigabyte in 2018.

I predict that around mid-2020 is when we will see the two types of drives reach parity. Then, I expect both to be selling for about 3 cents per gigabyte in the middle of 2020.

When will SSDs be cheaper than hard drives?

By late 2021, I expect SSDs to have the price advantage, selling for about 2 cents per gigabyte, while hard drives will still be closer to 3 cents per gigabyte.

I’ve seen predictions from people with more data than me that it may be closer to 2025 when the two types of storage reach price parity, but their data is older than mine too. I’ll go out on a limb and stick with my 2021 prediction.

But I will caveat that: Performance SSDs will carry a premium over these prices at any given time. That’s only fair; performance hard drives carry a price premium too.

What could change that

Yes, I am aware that flash memory has limitations and may run up against those limitations before 2021. But hard disk platters have limitations too–that’s one reason why hard drive prices aren’t dropping the way they have in the past. If flash memory does indeed run up against those limitations, another technology will replace it. Several companies think they are reasonably close to readying the successor to flash memory today.

Performance is worth a premium

I’ve been buying SSDs since 2009, when I bought an OCZ Vertex, the first budget SSD that could consistently outperform conventional hard drives. It made me a believer–this was long before OCZ’s now-infamous reliability issues–and I’ve been recommending them (and buying them myself) ever since. Compared to 2009 prices, SSDs are cheap now. The cost of a 960 GB SSD today is close to what a 1 TB hard drive cost in 2009.

I think they’re worth the premium. Back when your choices for storage were cheap, slow hard drives or faster, expensive hard drives, I always sprung for the faster hard drive, even if it meant buying a slower CPU and/or a motherboard that didn’t have as many slots in it. Storage has always been the biggest bottleneck in computing. So I’d buy the fastest storage I could get and watch my friends with faster CPUs wait on their slow hard drives. At the turn of the century I was buying 10,000 RPM SCSI drives, and paying a significant premium to do so because ATA speeds topped out at 7,200 RPM at the time and SCSI drives had NCQ but ATA drives didn’t. I was also putting 256 megabytes of RAM in them, which people told me was stupid. My computers were loud and fast.

Today I rarely buy the fastest SSD on the market, but even the slowest SSD outperforms the fastest hard drive, so I don’t have to.

So, write it down. When will SSDs be cheaper than hard drives? 2021. Maybe 2020. In the meantime, here’s how to save by buying used SSDs.