PowerSmart 21 in 170cc RWD DB8621S
The cheapest way into a rear wheel drive 3-in-1 gas mower, for sloped lawns on a tight budget. Expect less dealer support than a Toro.
Amazon $339.99$339.99
The PowerSmart 21 in 170cc RWD DB8621S is the better lawn mower overall, rated 3.8 to 3.3. The PowerSmart 21 in 170cc RWD DB8621S leads on value and power. The PowerSmart 21 in 170cc RWD DB8621S costs $126 less ($339.99 vs $465.99).
Greenworks 40V 21 in Self-Propelled
#16 in Self-propelledFull review
A low cost self propelled mower for lawns up to about a third of an acre, best if you already own Greenworks 40V tools.
Amazon $465.99$465.99
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the PowerSmart 21 in 170cc RWD DB8621S for value ($16.19 per inch of deck ($339.99, 21 in deck) vs $22.19 per inch of deck ($465.99 with batteries and charger, 21 in deck)) and power (170 cc engine vs 200 Wh of battery included).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every self-propelled lawn mower; a clear win is highlighted. How we rank explains each one.
| Factor weight | PowerSmart 21 in 170cc RWD DB8621S | Greenworks 40V 21 in Self-Propelled |
|---|---|---|
| Overall rating | 3.8/5 | 3.3/5 |
| Value 30% | 100 $16.19 per inch of deck ($339.99, 21 in deck) | 74 $22.19 per inch of deck ($465.99 with batteries and charger, 21 in deck) |
| Deck 20% | 12 21 in deck | 12 21 in deck |
| Power 15% | 62 170 cc engine | 14 200 Wh of battery included |
| Cutting modes 15% | 100 3 ways to cut: bag, mulch, side discharge | 100 3 ways to cut: bag, mulch, side discharge |
| Warranty 20% | 50 warranty not published (neutral score used) | 50 3-year warranty |
Specifications
| PowerSmart 21 in 170cc RWD DB8621S | Greenworks 40V 21 in Self-Propelled | |
|---|---|---|
| Cutting | ||
| Deck width | 21 in | 21 in |
| Deck | Steel | Steel |
| Cutting height | 1.5 to 3.9 in, 6 positions | 1.2 to 3.6 in, 7 positions |
| Bag | Yes | Yes |
| Mulch | Yes | Yes |
| Side discharge | Yes | Yes |
| Power | ||
| Power | Gas | Battery |
| Engine or battery | 170 cc | 40 V, 5 Ah of battery |
| Battery energy | - | 200 Wh |
| Battery included | - | Yes |
| Runtime | - | 40 min |
| Brushless motor | - | Yes |
| Electric start | No | - |
| Build | ||
| Drive | Rear-wheel drive | Rear-wheel drive |
| Folds upright | Yes | Yes |
| Weight | 59 lb | 61.7 lb |
| Warranty | - | 3 years |
| Battery warranty | - | 3 years |
| Released | - | 2024-01-20 |